United States.
Environmental Protection
Agency
Office of Water (WH 4304)
Washington. DC 20460
EPA822-B-S4-001
September 1994
&EPA BIOLOGICAL CRITERIA. w ^ " L
Technical Guidance for
Streams and Small Rivers
Printed on Recycled Paper
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BIOLOGICAL CRITERIA
Technical Guidance for
Streams and Small Rivers
Project Leader and Editor —•
Dr. George R. Gibson, Jr.
U.S. Environmental Protection Agency
Office of Science and Technology
fiealth and Ecological Criteria Division
401 M Street, SW (4304)
Washington, DC 20460
Principal Authors
Dr. Michael T. Barbour, Principal Scientist
Dr. James B. Stribling, Senior Scientist
Dr. Jeroen Gerritsen, Principal Scientist
TetraTech, Inc.
10045 Red Run Boulevard, Suite 110
OwingsMill, MD21117
Dr. James R. Karr, Director
Institute for Environmental Studies
Engineering Annex.FM-12
University of Washington
Seattle, WA 98195
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3IC$.GG:CAL CRITERIA:
Technical Guidance for Streams and Small Rivers
Prepared by JT&A, inc., and Abt Associates for the U.S. Environ-
mental Protection Agency. Points of view expressed in this publica-
tion do not necessarily reflect the views or policies of the U.S.
Environmental Protection Agency, nor does mention of trade names
or commercial products constitute an endorsement or recommenda-
tion for their use.
Address comments or suggestions related to this document to
Dr. George R. Gibson, Jir.
U.S. Environmental Protection Agency
Office of Science and Technology
Health and Ecological Criteria Division
401 M Street, SW (4304)
Washington, DC 20460
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1 * '•%'"'
Acknowledgments
Dr. George Gibson of the Office of Science and Technology's Health
and Ecological Criteria Division is project leader and principal edi-
tor of this document whose principal authors are consultants Drs.
Michael Barbour, James Stribling, Jercxm Genitsen, and James Karr.
Dr. Phil Larsen of the U.S. Environmental Protection Agency's Envi-
ronmental Research Laboratory in Corvallis, Oregon; and Dr. David
Courtemanch of the Department of Environmental Protection in Augusta,
Maine, also provided valuable insights and wrote portions of the docu-
ment. Staff from several program offices in the Office of Water provided
expert advice and made comments on the text, and Rachel Reeder of
JT&A, inc., helped weave the text with its multiple contributions into a
more cogent document. —
Many others also contributed to the writing of this document and de-
serve special thanks: first and foremost, the Streams Biocriteria Work-
group. The Workgroup, composed of state and EPA biologists, members of
academic institutions, and other consultants, helped provide the frame-
work for the basic approach and served as primary reviewers of the manu-
script. Next, our special thanks to those scientists who responded to our
request for peer review and to the members of the Ecological Processes
and Effects Committee of the Science Advisory Board (SAB), who also re-
viewed the manuscript and prepared an insightful critique. We sincerely
appreciate the contribution of their valuable time and constructive advice.
Their comments have greatly improved the final document
Streams Biocriteria Workgroup
• George R. Gibson, Ph.D., Workgroup Chair, U.S. EPA Health and Ecological
Criteria Division •
• Michael Barbour, Ph.D., Tetra Tech, Inc. :
• Ed ward Bender,Ph.D., U.S. EPA Science Advisory Board .
• Lawrence Douglas, PhD., University of Maryland
• Chris Faulkner, U.S. EPA Assessment and Watershed Protection Division
• James Karr, Ph.D., University of Washington, Institute for Environmental Studies
• D. Phil Larsen, Ph.D., LJ.S. EPA Environmental Research Laboratory, Coroallis
? James Lazorchak, U.S. EPA Environmental Monitoring Systems Laboratory,
Cincinnati
• Dave Penrose, North Carolina DEM, Environmental Services Laboratory
• James O. Peterson, Ph.D., University of Wisconsin
• Ron Preston, U.S. EPA Region 3, Wheeling Division
• Stephanie Sanzone, U.S. EPA Science Advisory Board
• Christopher Zarba, U.S. EPA Health and Ecological Criteria Division
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Contents
Acknowledgments iii
List of Figures ...................viii
List of Tables .-.-, xl
CHAPTER 1: Introduction ..-. .'.... .1
The Concept of Biocriteria ..... .,. .2
The Development, Validation, and Implementation
Process for Biocriteria ..,.......... \. 3
Characteristics of Effective Biocriteria ... 1 .8
Examples of Biocriteria... .................................. 9
Narrative Biological Criteria ......_,........ .............. .9
Numeric Biological Criteria ... ................. .10
Other Biocriteria Reference Documents ........... 11
Suggested Readings .........; — .11
CHAPTER 2: Components of Blocritoria .',. .13
Conceptual Framework and Underlying Theory .. 13
Components of Biological Integrity . <. .14
Assessing Biological Integrity ..... .16 '
Complex Nature of Anthropogenic Impacts „ 17
The Biocriteria Development Process . ....................... 19
Suggested Readings .23
CHAPTER 3: The Reference Condition ............, .25
Establishing the Reference Condition .................; .25
The Use of Reference Sites , 27
Characterizing Reference Conditions 30
Classification ........30
Framework for Preliminary Classification ...... .31
Site Selection . .',-..;..'...' .......;............. .37
Confirmation Y....,..' .39
Suggested Readings ,....-.. — .. .42
CHAPTER 4: Conducting the Bionurvey 43
The Quality Assurance Plan 44
Quality Management ............:. .45
Biocriteria Program Structure, Personnel, and Resources .45
Quality Control Elements in an Ecological Study ... .48
Data Quality Objectives .52
Study Design .............. ..........53
Biosurveys of Targeted Assemblages ....,; .54
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BlQLOdlUAL UHIJEHIA:
Technical Guidance for Streams and Small Rivers
Attributes of Selected Assemblages 54
Synthesis ' 57
Technical Issues 58
Selection of the Proper Sampling Periods 59
. Selection of Habitat for Aquatic Assemblage Evaluations 65
Substrate Choices .... 68
Natural and Artificial Substrates 69
Standardization of Techniques 70
Sample Collection 70
Sample Processing .71
Suggested Readings 72
CHAPTER 5: Evaluating Environmental Effects 75
Water Quality i .75
Habitat Structure .. 77
Habitat Quality and Biological Condition 80
Development of Habitat Assessment Approach 81
Flow. Regime .82
Energy Source 85
Biotici Interactions .x 87
Cumulative Impacts ......'.... , ... .87
Suggested Readings 89
CHAPTER 6: Multimetrlc Approaches for Blocrltoria Development 91
Metric Evaluation and Calibration 92
Biocriteria Based on a Multimetric Approach 95
Potential Metrics for Fish and Macroinvertebrates 99
Index Development 104
Other Developments 107
Suggested Readings 107
CHAPTER 7: Biocriteria Development and Implementation 109
Establishing Regional Biocriteria .109
Designing the Actual Criterion 110
Biocriteria for Significantly Impacted Areas 112
Selecting the Assessment Site 112
Evaluating the Site Assessment 114
Overview of Selected State Biocriteria Programs .117
Costs for State Programs Developing Bioassessments and Biocriteria 122
Value of Biocriteria in Assessing Impairment 126
Suggested Readings 130
CHAPTER 8: Applications of Biocriteria 131
Aquatic Resource Characterization 131
Case Study — North Carolina — 132
Refining Aquatic Life Uses 133
Judging Use Impairment 135
Case Study — Ohio 136
Diagnosing Impairment Types 137
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Case Study — Delaware
Compliance Monitoring......
Case, Study — Maine
Suggested Readings .......
Contacts for Case Studies
Glossary .........
Reference)! . ,
.139
.139
.141
.143
.143
.145
.151
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3>GL.-3GiC*L ^niitfilA. -••••• ' -
Tec'nmcal Guidance for Streams and Small Rivers
List of Figures
Figure t-1.—Model for biocriteria development and application .. 4
Figure 2-1.—Conceptual model showing the interrelationships of the primary
variables relative to the integrity of an aquatic biota. External refers to
features outside the stream system; internal to in-stream features (Karr.
1991). Terrestrial environment includes factors such as geology, topography,
soil, and vegetation. .. 18
Figure 2-2.—Organizational structure of tho attributes that should be
incorporated into biological assessments. .................................. 19
Rgure 3-1 .-—Approach to establishing reference conditions. 28
Figure 3-2.—Reciprocal averaging ordination of sites by fish species in the
Calapooia River watershed, Oregon. The inset shows the correspondence
between-fish assemblages in the rivers and ecoregions 35
Figure 3-3.—Generalized box-and-whisker plots illustrating percentiles and
the detection coefficient of metrics. 39
Figure 3-4.—Index of Biotic Integrity at Ohio reference sites. ....... 41
Rgure 3-5.—Fish species richness as a function of the tog of watershed
area. Bars to right indicate range of'observations before regression and
range of residuals after regression. Residuals have smaller variance than .
the origins] observations. 41
Rgure 4-1 .—Organization chart illustrating project organization and lines of
responsibility. 48
Figure 4-2.—Summary of Data Quality Objective (OQO) process'for
ecological studies (taken from Barbour and Thomley, 1990). — 52
Rgure 4-3.—Classification of U.S. climatological regions. 61
' ' ' - '. - "" /•
Rgure 4-4.—Biological and hydrological factors for sampling period selection
in the Northeast (macroinvertebrates). The gray area is the overlap between
emergence and recruitment. 63
Rgure 4-5.—Biological and hydrological factors for sampling period selection
in the Northeast (fish) ,..'..- ', 64
Figure 5-1.—Rve major classes of environmental factors that affect aquatic
biota in lotic systems. Right column lists selected expected results of
anthropogenic perturbation (Karr et al. 1986). 76
Rgure 5-2.—Decision matrix for application of rapid btoassessments in
Arkansas for permitted point source discharges (Shackleford, 1988). ........... 78
Rgure 5-3.—Qualitative Habitat Evaluation Index (QHEI) versus Index of
Biotic Integrity (IBI) for 465 relatively unimpacted and habitat modified Ohio
stream sites (Rankin, 1991) •,•••• 80
Rgure 5-4.—Choptank and Chester rivers tributaries (Primrose et al. 1991). 81
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Contents
List of Tables
Table 2-1.—Components of biological integrity (modified from Karr, 1990). .. . 15
Table 3-1.—Hierarchical classification of stream riparian habitats (from
Minshall, 1993; afterFrissell etal. 1986) ....,...;..... .....v 34
Table 4-1.—Quality control elements integral to activities in ah ecological
study in sequence. „.-. i.-.......... .49
Table 4-2.—Common benthfc habitats 68
Table 4-3.—Proposed,minimal levels of taxonomic resolution for stream
macroinvertebrates (taken from Sci. Advis. Board. 1933). 72
Table 5-1.—Parameters that may be useful in evaluating environmental
conditions and their relationship to geographic scales and the environmental
factors influenced by human actions. .79
Table 6-1.— Sequential progression of trie"bkwriteria process.....;........... .99
Table 6-2.—Index of Blotic Integrity metrics used in various regions of North
America. .. —•.. .'......... 101
Table 6-3.—Examples of metric suites used for analysis of
macroinvertebrate assemblages.-. .: 102
Table 6-4.—IrKJex of Biotic Irtegrity metrics and scoring criteria based on
fish community data from more than 300 reference sites throughout Ohio
applicable only to boat (!.«., nonwadable) sites. Table modified from Ohio '
EPA (1987) : , ...... 105
Table 6-5.—-Ranges for Index of Biological Integrity values representing
different narrative descriptions of fish assemblage condition in Ohio streams.
Site category descriptions—wading, boat, and headwaters — indicate the
type of site and style of sampling done at those sites. Modified from Ohio
EPA (1987). '.'....... .:,............................ 106
Table 7-1.—Sequential process for assessment of test sites and
determination of the relationship to established biocriteria. 115
Table 7-2.—Maine's water quality classification system for rivers and
streams, and associated biological standards (taken from Davieset aJ. 1993). ... 118
Table 7-3.—Bioclassification criteria scores for EPT taxa richness values for
three North Carolina eeoregions based on two sampling methods. ... . 120
Table 7-4.—The investment of state water resource agency staff to develop
bioassessment programs as a framework for btocriteria. .126
Table 7-5.—Costs associated with retaining consultants to develop
bioassessment programs as a framework for hiocriteria. Dash indicates work
done by state employees or information not available; FTE costs for
contractors and state employees are not equivalent 126
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Figure 5-5.—Relationship of the Index of Biotic Integrity (IBI) to changes in
the quality of habitat structure through the Qualitative Habitat Evaluation
Index (QHEi) in channelized (triangles) and unchannelized (circles) (Ohio
EPA, 1990) ' 84
Rgure 5-6.—Diagrammatic representation of the stream continuum to
illustrate variation in trophic structure of benthic invertebrates (adapted from
Cummins, 1983) 86
Rgure 5-7.—Biological community response as portrayed by the Index of
Biotic Integrity (IBI) in four similarly sized Ohio rivers with different types of
point and nonpolnt source impacts (Voder, 1991) 89
Rgure 6-1 a.—Metrics that decrease with impairment '..:.-. .. 92
Rgure 6-1b.—Metrics that increase with impairment. ...... 93
Rgure 6-2.—Total number of fish species versus stream order for 72 sites
along the Embarras River In Illinois (Fausch et al. 1984). 94
Rgure 6-3.—Metrics plotted with a continuous covariate (hypothetical
example) 94
Rgure 6-4.—Box and whisker plots of mejric values from hypothetical
stream classes. Shaded portions above the median for each class. The box
represents a percentile, the vertical line is 1.5 times the interquartile range,
and the horizontal line is the median of each distribution. .; 95
Rgure 6-Sa.—Site discrimination for the number of Ephemeroptera,
Plecoptera, and Trichoptera (EPT index) in Rorida streams. (Reference •
least impaired, other » unknown, impaired » determined impaired a priori.) 96
Rgura 6-5b.—Site discrimination for the number of Chironomidae taxa in
Rorida streams. (Reference *least impaired, other * unknown, impaired »
determined impaired a priori.) 96
Rgure 6-6.—Tiered metric development process (adapted from Holland,
1990) ;...., 97
Rgure 6-7.—The conceptual process for-proceeding from measurements to
indicators to assessment condition (modified from Paulson et al. 1991). ..... 98
Rgure 6-8.—Invertebrate stream index scores for Rorida streams .106
Rgure 7-1.—Hierarchy of statistical models used in Maine's biological
criteria program (taken from Oavies et al. 1993) 111
Rgure 7-2.—The process for proceeding from measurements of fish
assemblage to indicators such as the Index of Biotic Integrity (IBI) or Index
of Well Being (IWB) — as used to develop criteria and apply those criteria to
streams (modified from Paulsen et al. 1991) 116
Rgure 7-3a—Biological criteria in the Ohio WQS for the Warmwater Habitat
(WWH) and Exceptional Warmwater Habitat (EWH) use designations
arranged by biological index, site type for fish, and ecoregion (Ohio EPA,
1992). ..; 122
Rgure 7-3b.—Biological criteria in the Ohio WQS for the Modified
Warmwater Habitat (MWH) use designation arranged by biological index,
site type for fish, modification type, and ecoregion (Ohio EPA, 1992) 123
Rgure 7*4.—Comparison of ambient toxicity and fish richness surveys at
eight sites in various parts of the United States (taken from U.S. EPA, 1991).
127
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3ICLCGICAL CRITERIA: v .
Technical Guidance for Streams and Small Rivers
Figure 7-5.—Comparison of effluent toxicity of receiving water impact using
Ceriodaphnia dubia chronic toxicity tests and freshwater receiving stream
benthfc invertebrates at 43 point source discharging sites in North Carolina
(taken from U.S. EPA, 1991). : ... 128
Figure 7-6.—Comparison of chemical criteria exeeedances and biosurvay
results at 645 stream segments in Ohio. 128
Figure 7-7.—Assessment of nontidal stream aquatic life use attainment in
Delaware (taken from the state's 395[b] report, 1994). 128
Figure 8-1.—EPT Index (number of taxa of Ephemeroptera, Plecoptera, and •
Trichoptera) for two (locations on the South Fork of the New River, North
Carolina. . ....... 132
Figure 8-2,—Examples from some states using biological assessments to
determine aquatic life use support in rivers and streams. Failure to sustain
fish and aquatic fife is defined with respect to the reference condition in that
state .....„..........;. . :•. •.-
135
Figure 8-3-—Temporal trends in the improvement of the Upper Hocking
River, illustrating the Area of Degradation Value (ADV). 1982 -1990. .......... 137
Figure 8=4—State off Delaware 305(b) report for nontidal stream use
attainment — aquatic life 1992.. 140
Figure 8-5,—Assessment summary, Kent and Sussex counties, Delaware,
1991 :. 140
Figure 8-6,,—Macroiiwertebrates in the Piseataquis River, Maine, 1984 -
1990 .... ..*.; »...- . ........;......... 142
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CHAPTER 1.
Introduction
The goal of this support document is to help states make decisions and
develop biocriteria for streams and small rivers. The document in-
dudes a general strategy for biocriteria development, identifies steps in
the process, and provides technical guidance on how to complete each
step, using the experience and knowledge of existing state, regional, and
national surface water programs.
, Specifically, biocriteria provide~"a way to measure the condition of a
water resource, that is, its attainment or nonattainment of biological integ-
rity. In turn, biological integrity is a conceptual definition of the most ro-
bust aquatic community to be expected in a natural condition—in a water
resource unimpaired by human activities. Thus, biological criteria are the
benchmarks for water resource protection and management; they reflect
the closest possible attainment of biological integrity. It follows that any
criterion representing less than achievable biological integrity is an interim
criterion only, since the use of biocriteria are intended to improve the
nation's water resources. .
The guidance in this document is designed so that users may tailor ap-
propriate methods to their particular biocriteria development needs.
Chapters 1 and 8 are inclusive of the methodology — at different levels of
complexity — while chapters 2 through 7 explore the process step by step.
Thus, the document is organized as follows:
• Chapter 1: Introduction. An overview of biocriteria. ,
• Chapter 2: Components of Biocriteria. An exploration of the bask re-
lationship between biological integrity and biocriteria, the complex
nature of human disturbances, and the definition of biological ex-
pectations.
• Chapter 3: The Reference Condition. Selection of reference sites and
the role of the reference condition in Biocriteria development
• Chapter 4: Conducting the Biosurvey. An investigation of the de-
sign, management, and technical issues related to biocriteria-
bioassessment programs, the various biosurvey methods and their
standardization.
. • Chapter 5: Evaluating Environmental Effects. Factors that affect
water resource integrity.
Purpose:
To provide conceptual
guidance on
how and when to
use biocriteria
-bioassessments to
evaluate ecological
integrity.
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siCLOGiCAL CRITERIA:
. Technical Guidance for Streams and Small Rivers
Biocriteria can be
developed from
expectations of the
region or watershed,
site-specific
applications, or
consensus definitions
from regional
authorities. Biocriteria
based directly on
biological sampling,
however, require
minimally impaired
reference sites
against which the
study area may be
compared.
m Chapter 6: Multimetric Assessment Approaches for Biocriteria De-
velopment. Emphasis on the community composition element of
biological surveys.
• Chapter 7: Biocriteria Development and Implementation. Designing
and developing biocriteria from the data and precautions for some
site selections.
• Chapter 8: Applications of Biocriteria. Case Studies from North
Carolina, Ohio, Delaware, and Maine.
Each chapter concludes with a list of readings containing supplemen-
tal information on the specific topic treated in that chapter. An extensive
glossary and full reference list appear at the end of the document Future
documents will be oriented to other waterbody types: lakes and reservoirs,
rivers, estuaries near coastal marine waters, and wetlands.
The Concept of Biocriteria
Early efforts to monitor human effects on waterbodies in the 19th century
were limited to physical observations of sediment and debris movement
resulting from urban development, land settlement, and commercial activ-
ities (Caper et aL 1983). Later, as analytical methods became increasingly
available for measuring microchemical conditions in the waterbody (Gib-
son, 1992), chemical measurements became the most commonly employed
source of water quality criteria. However, investigators and resource man-
agers have long recognized that water column measurements reflect con-
ditions only at the time of sampling.
To understand fully the effects of human activities on water resources,
biological sampling is an important supplement to chemical sampling. Bi-
ological measurements can reflect current conditions and temporal
changes in waterbodies, including the cumulative effects of successive dis-
turbances.
Three aspects of water resource management (chemical, physical, and
biological) are recognized in-the National Clean Water Act as amended by
the,Water Quality Act of 1987 (U.S. Gov. Print. Off. 1988). Section lOla
states that the Acf s primary objective is to "restore and maintain the
chemical, physical, and biological integrity of the nation's waters."
The development and widespread use of formal biological criteria
(biocriteria) has lagged behind chemical-specific, in-stream flow, or tox-
icity-based water quality criteria in waterbody management (U.S. Environ.
Prot. Agency, 1985a,b; 1986). Biological criteria are numeric values or nar-
rative expressions that describe the biological condition of aquatic commu-
nities in the water at a designated reference site. The conditions of aquatic
life found at these reference sites are used to detect both the causes and
levels of risk to biological integrity at other sites in the same region. In
keeping with the policy of not degrading the resource, the reference condi-
tions — like the criteria — are expected to be upgraded with each im-
provement to the water resource. Thus, biocriteria contribute directly to
water management programs, and recent recommendations (U.S. Environ.
Prot. Agency, 1987a,b) on monitoring strategies for aquatic resources have
emphasized the need to accelerate the development of biological sampling
as a regular part of surface water programs.
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•introduction
. Biocriteria can be developed from expectations for the region-or water-
shed, site-specific applications, or consensus definitions from regional au-
thorities. Biocriteria based directly on biological sampling, however,
require minimally impaired reference sites against which the study area
may be compared. Minimally impaired sites are not necessarily pristine;
they must, however exhibit minimal disturbance (i.e., human interference)
relative to the overall region of study. Ecological integrity is the condition
of an unimpaired ecosystem as measured by combined chemical, physical
(including habitat)/and biological attributes.
The use of biocriteria expands and improves water quality standards,
helps identify impairment of beneficial uses, and helps set program priori-
ties. Biological surveys (or biosurveys), in conjunction with biocriteria, are
valuable because they provide
• a direct measure of the condition of the water resource at the site,
• early detection of problems that other methods may miss or
underestimate, and ! .
• a systematic process for measuring the effectiveness of water resource
management programs. . _ :
The Development, Validation, and
Implementation Process for Biocriteria
Three processes are part of the overall implementation plan to incorporate
biocriteria into the surface water programs of regulatory agencies: the de-
velopment of biocriteria and associated biological survey methods, the
validation of the reference condition and bioassessment techniques, and
the implementation of the program at various sites within watersheds arid
subsequent determination of impairment
The development of biocriteria by regulatory agencies partly depends
on bioassessment to evaluate or compare ecosystem conditions. Bioassess-
ment contains two types of data: toxidty tests and field biological surveys
of surface waters. Toxicity tests are described elsewhere (U.S. Environ.
Prot. Agency, 1985a,b; 1988; 1989) and are not the subject of this document
The use of bioassessments to investigate potential impairment, evalu-
ate the severity of problems, ascertain the causes of the problems, and de-
termine appropriate remedial action is a step-by-step process.
Inherent in the process for implementation of biocriteria is the as-
sumption that bioassessment methods have been developed. However, the'.'
actual development of biocriteria is the most difficult step in the whole
process. A conceptual model for biocriteria development was presented by
the U.S. Environmental Protection Agency (1990) to streamline the major
elements in the process. This model has been refined for presentation here
(Fig.1-1).
Each component of the model is numbered so that it can be identified
and discussed more easily as an important part of the biocriteria develop-
ment process. Nevertheless, these steps are not sequential. The following
paragraphs describe the model process in more detail and identify areas of
simultaneous development.
I he process is
essentially the
comparison of
biological and habitat
measurements at a
site of concern to
"benchmarks" or
biocriteria derived
from similar
unimpaired streams h
that area. A notable
deviation is reason for
further investigation
and remedial action.
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3tCl.OGiCAL CRITERIA.
Technical Guidance for Streams and Small Rivers
Ewkato Be
en'EMluMin of CMi
t VWhlntt* Rnlwd RanwMft)
12
13 OfegnoMCauMoflniiainram
14
NoAeSonR«|ui(»d;Co<*nue
Ch.1
Ch.2
Ch.3
Ch.3
Ch.4
Ch.4
Ch.4
Ch.2
Ol. 2.3.5,7
Ch.4.9.1
Ch.4,S.8.7
Ch.8.7
Ch.S.t.7
Ch.7
Figure 1-1.—Model for blocrltcria development and •ppllcatlo'n.
Components 1 through 8 desoibe the development of biocriteria, prior
to their use in regulatory programs. ,
1. Investigate the Biocriteria Program Concept The biocriteria proc-
ess involves the selection of several program elements that contrib-
ute to effective biocriteria. Each state agency will have its own
program objectives and agenda for establishing biocriteria; how-
ever, the underlying characteristics for effective biocriteria will be
the same in all states.
2. Formulate the Biocriteria Approach. Defining biological integrity
is the first step in the formulation of a biocriteria program (U.S.
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CHAPTEfl'1:
Introduction
Environ. Prot. Agency, 1990). The activities important to this step
are planning the biocriteria process; designating the reference con-
dition; performing the biosurveys; and establishing the biocriteria.
3. Select Reference Sites or Conditions. The attainable biological sta-
tus of an aquatic system is described by the reference condition, if
we understand the water resources's biological potential, we can
judge the quality of communities at various sites relative to their
potential quality. Natural environmental variation may contribute
to a range of expected conditions; deviations from this range help
to distinguish perturbation effects. ,
Reference conditions can also be derived from historical
datasets existing from previous studies. These data range from
handwritten field notes to published journal articles; however, bio-
logical surveys of reference sites that are minimally impaired is still
the most appropriate way to define the reference condition.
The selection of reference sates is key to the success of biocrite-
ria development. Various spatial scales can be used/but reference
conditions must be representative of the resource at risk ai\d must,
therefore, be of the same or similar ecological realm or biogeo-
graphic region (i.e., an area characterized by a distinctive flora or
fauna).
Candidate reference sites can be selected in a number of ways,
but must meet some requirements established on the basis of overall
habitat and minimally impaired status" in a given region. The refer-
ence condition is best described through data collected from several
reference sites representing undisturbed watersheds. Such biologi-
cal information can be combined for a more accurate assessment of
the reference condition and its natural variability. The reference con-
dition approximates the definition of biological integrity unless the
reference sites were selected in significantly altered systems.
4. Select Standard Protocols. The development of standard protocols
requires consensus building relative to the biological and ecological
. endpoints of interest in creating biocriteria. The primary goal is to de-
velop measures to assess the biological integrity of aquatic communi-
ties in specified habitats as measured by biological elements and
processes, that is, as measured by the activities that maintain commu-
nities in equilibrium with the environment There is no correct
method to use or biological assemblage to sample; rather, a number pf
possibilities exist, including the Index of Biotic Integrity (IBI) for fish,
and the Rapid Bioassessment Protocols (RBP) for benthos.
The process of applying these and other indices across widely
differing systems is not a straightforward process and best profesr
sipnal judgment should be exercised before applying them to spe-
cific problems. For example, the IBI must be modified for
northwestern assemblages since it was developed in the Midwest
for midwestem assemblages. These indices measure some struc-
tural or functional attribute of the biological assemblage that
changes in some predictable way with increased human influence.
Combinations pf these attributes or metrics provide valuable syn-
The selection of
reference sites is key
to the success of
biocriteria
development. Various
spatial scales can be
used, but reference
conditions must be
representative of the
resource at risk and
therefore, must be of
the same or similar
ecological realm
(or biogeographic
region).
The process of
applying indices
across widely ,
differing systems is
not a straightforward
process and best
professional judgment
should be exercised
before applying them
to specific problems.
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BIOLOGICAL CRITERIA.
Technical Guidance for Streams and Small Rivers
thetic assessments of the status of water resources. The basic theo-
retical framework and approach should remain consistent. There-
fore, the use of these indices should occur only after rigorous
review and evaluation of their documentation. Such reviews are
available in a variety of peer-reviewed publications.
5. Modification and Refinement of the Protocols. The refinement
process is an .important step before large-scale biosurveys are con-
ducted. The sensitivity of the protocols should be tested to deter-
mine whether differences in community health resulting from
anthropogenic activities are discernible from changes caused by
other impacts or natural variation. An impact is any change in the
chemical, physical or biological quality or condition of a water-
body caused by external sources. This process applies to all aspects
of the protocol from sampling to data analysis and may be re-
. peated as often as necessary.
6. Address Technical Issues. Certain technical issues — for example,
natural seasonal variability, the aquatic assemblages selected for eval-
. uation, the procedure for selecting sampling sites, and the type of
sampling gear or equipment—affect the derivation of biocriteria.
7. Characterize Biological Integrity. Analyze biological databases to
establish the range of values of the reference condition and to charac-
terize biological integrity. Characterization depends on the use of bio-
logical surveys in conceit with measurements of habitat structure.
8. Establish Biocriteria and a Biological Monitoring Program. Once
biological integrity has been characterized and the geographic area
has been regionalized, biological information can be equated to the
water quality expectations of the state, and biocriteria can be estab-
lished for these regions. Biocriteria may vary within a state de-
pending on the region's ecological structure and the type of
monitoring used in its water quality programs. Biological monitor-
ing, or biomonitoring, is the use of a living entity and its response
as a measure to determine environmental conditions. It is necessary
to assess and track changes in the condition of the surface water re-
source and reference conditions.
Step 9 describes the validation of the biocriteria developed in the pre-
vious components.
9. Evaluate and Revise. Revision of the biocriteria approach uses ex-
isting biological data to determine or explain the regional limits for
biocriteria. This step includes statistical analyses of biological,
physical, and chemical data to establish natural variability and the
validity of existing biocriteria. Regional frameworks should be ad-
justed if biological and geographical data support the need to do
so. Reasons for these adjustments and the data used to determine
- them should be dearly documented.
Steps 10 through 14 describe the use of biocriteria for water resource
management, that is, for the assessment, remediation, and regulation of
water quality.
-------
Introduction
10. Conduct Biosurveys. Biosurveys conducted at test sites help to de-
- termine whether and to what extent a site deviates from the normal
range of values observed fprthe reference conditions. This measure
will also establish a site's degree of noncompliance with regional
biocriteria. Candidate test sites are any locations along the stream
or river in which the conditions are not known but are suspected of
being adversely affected by anthropogenic influence.
11. Detect Impaired and Nonimpaired Conditions. Decisions on
whether adverse or impaired conditions exist must be made, but
whether these conditions are socially tolerable may be beyond sci-
ence. Scientists and resource managers are/ however, obliged to de-
termine the relative impairment of the water resource as a
precondition for any subsequent decision.
12. Review Other Data Sources for Additional Information. The use
* of additional data to support or provide alternatives to the biological
assessment is important in the decision-making process. As part of an
integrated approach, whole effluent toxicity (WEI) testing and chemi-
cal-specific analyses can be-performed .to measure compliance with
state standards. Any of three measures —.biological, toxicological, or
chemical — can be used to demonstrate; impairment
13. Diagnose Causes of Impairment Once impairment has been de-
termined, its probable causes must be identified before remedial
action can be considered and implemented. Probable 'causes* may
include alteration pf habitat structure, energy source, biological in-
teractions, flow characteristics, or water quality. The "source" of
the disturbance may be point or nonpoint source contamination or
other human activities. Thus, if impairment is detected, the data
should be evaluated to determine its probable causes; the site and
surrounding area should be investigated for other probable causes;
additional data should be collected; and either remedial action
should be formulated (if the actual causes have been determined)
or the investigation should be continued.
14. Implement Remedial Actions and Continued Monitoring. If
probable causes have been determined so that*a remedial action
plan can be developed, the last step is to begin remedial measures
and continue monitoring to assess the stream's recovery and rela-
tive success of the measures. This step can be useful for evaluating
management programs and determining cost-effective methods.
Selection of the appropriate remedial actions is a step beyond the
biocriteria process; however, it is essential to reduce or eliminate
impairment to attain the designated uses that the biocriteria .were
derived to protect, the process of remediation or prevention must
be addressed by the state agency responsible for enforcement and
protective or restoration programs.
If no impairment is found, no action is necessary except to con-
tinue monitoring at some interval to ensure that the condition does
not change adversely.
-------
atOLOGtCAL CPlTEfllA:
• Technical Guidance for Streams and Small Rivers
The best balance is
achieved by
developing biocriteria
that closely represent
the natural biota,
protect against further
degradation, and
stimulate restoration
of degraded sites.
Characteristics of Effective Biocriteria
Generally, effective biocriteria share several common characteristics. Well-
written biocriteria
• provide for scientifically sound evaluations,
• protect the most sensitive biological value,
• protect healthy, natural aquatic communities,
• support and strive for protection of chemical, physical, and biological
integrity,
• include specific assemblage characteristics required for attainment of
designated use,
• are dearly written and easily understood,
• adhere to the philosophy and policy of nondegradation of water
resource quality, and
' • are defensible in a court of law.
In addition, well-written biocriteria are set at levels sensitive to anthro-
pogenic impacts; they are not set so high that site; that have reached their
full potential cannot be rated as attaining, or so low that unacceptably im-
paired sites receive passing scores. The establishment of formal biocriteria
warrants careful consideration of planning, management, and regulatory
goals and the best attainable condition at a site. Stringent criteria that are
unlikely to be achieved serve little purpose. Similarly, biocriteria that sup-
port a degraded biological condition defeat the intentions of biocriteria de-
velopment and the Clean Water Act Balanced biocriteria will incorporate
multiple uses so that any conflicting uses are evaluated at the outset. The
best balance is achieved by developing biocriteria that closely represent
the natural biota, protect against further degradation, and stimulate resto-
ration of degraded sites.
Additional general guidance regarding the writing of biocriteria is pro-
vided in U.S. Environ. Prot Agency (1990). Several kinds of biocriteria are
possible and vary among state programs. Both narrative and numeric
biocriteria have been effectively implemented. Both should be supported by
effective implementation guidelines and adequate state resources, including
people, materials, methods, historical data, and management support.
Narrative biocriteria consist of statements such as "aquatic life as it
should naturally occur" or "changes in species composition may occur, but
structure and function of the aquatic community must be maintained." An
aquatic community, the association of interacting assemblages in a given
waterbody, is the biotic component of an ecosystem. Numeric values, such
as measurements of community structure and function, can also serve as
biocriteria. The numeric criterion should be a defined range rather than a
single number to account for a measure's natural variability in a healthy
environment. It may also combine several such values in an index. General
descriptions of actual narrative and numeric biocriteria from selected state
programs are presented in the following section; the information was
taken from Biological Criteria: State Development and Implementation Efforts
(U.S. Environ..Prot. Agency, 1991a).
-------
CHAPTER 7:
Introduction
Examples of Biocriteria
Three states have adopted biocriteria for water quality management
Maine and North Carolina use narrative criteria; Ohio has implemented
combined narrative and numeric criteria.
Narrative Biological Criteria
States may draft general narrative biological criteria early in their program
— even before they have designated reference sites .or refined their ap-
proach to biological surveys. This haste does not mean that having refer-
ence sites and a refined system for conducting surveys is unimportant; it
means that a biocriteria program begins with writing into law a statement
of intent to protect and manage the water resources predicated on an
objective or benchmark, for example, "aquatic life shall be as naturally
occurs."
When the objective to restore and protect the biological integrity of the
water resources has been formally mandated, then the operational mean-
ing of the statement and the identification of the agency responsible for
developing the necessary procedure!} and regulations can be stipulated as
the state's first steps toward the development of narrative and numeric bi-
ological criteria. The key point is that natural or minimally impaired water
resource conditions become the criteria for judgment and management.
For more definitive and specific information on this concept and its imple-
mentation, the reader is referred to the EPA guidance document "Proce-
dures for Initiating Narrative Biological Criteria" (Gibson, 1992).
Once established in state standards, narrative biological criteria form
the legal and programmatic basis for expanding biological surveys and as-
sessments to complete narrative criteria and to develop subsequent nu-
meric biological criteria. ,
Maine and North Carolina are examples of the practical development
and use of narrative biological criteria. Maine incorporated the general
statement "as naturally occurs" into its biocriteria, but also developed sup-
porting statements that specified collection methods to survey aquatic life.
Maine uses narrative biocriteria thai: are defined by specific ecological at-
tributes, such as measures of taxonomic equality, numeric equality, and the
presence of specific pollution tolerant or intolerant species. ^
North Carolina uses narrative criteria to evaluate point and nonpoint
source pollution and to identify and protect aquatic use classifications. In
North Carolina, macroinvertebrate community attributes are used to help
define use classifications. These attributes include taxonomic richness and
the biotic indices of community functions and numbers of individuals.
They are also used in conjunction with narrative criteria to determine
"poor," "fair," good—fair," good," and "excellent" ratings for the desig-
nated uses. -
Narrative biological criteria specify the use designations established
by the state and describe the type of water resource condition that repre-
sents the fulfillment of each use. Conversely, when adopted by the state
and approved by EPA, they become one of the standards by which water
resource violations are determined.
<
States may draft
general narrative
biological criteria
early in their program
-— even before they
have designated
reference sites or
refined their approach
to biological surveys.
,
Narrative biological
criteria cannot be fully
implemented without
a quantitative
database to support
them.
-------
. ur« / cnut.
Technical Guidance for Streams and Small Rivers
Numeric biocriteria
include discrete
quantitative values
that summarize the
status of the
biological community
and describe the
expected condition of
this system for
different designated
water resource uses.
i
Nevertheless, narrative biological criteria cannot be fully implemented
without a quantitative database to support them. Quantitative data pro-
vide a responsible rationale for decision making and assure resource man-
agers a degree of confidence in their determinations.
These data are similar to the data used to formulate numeric biological
criteria; they can and should include the determination of reference condi-
tions and sites. Thus, when the survey process for narrative biocriteria is
weU developed and refined, the program can easily begin the develop-
ment of numeric biocriteria. While not an essential precursor, the narrative
process is an excellent way for states to expand their stream resource eval-
uation and management procedures to the more definitive numeric
biocriteria.
Numeric Biological Criteria
Although based on the same concept a* narrative biocriteria, numeric
biocriteria include discrete quantitative values that'summarize the status
of the biological community and describe the expected condition of this
systemfpr different designated water resource uses.
The key distinction between narrative biocriteria supported by a quan-
titative database and numeric biocriteria is the direct inclusion of a specific
value or index in the numeric criteria. This index allows a level of specifi-
cation to water resource evaluations and regulations not common to narra-
tive criteria.
To develop numeric criteria, the resident biota are sampled at mini-
mally impaired sites to establish reference conditions. Attributes of the
biota, such as species richness, presence or absence of indicator taxa, and
distribution of trophic groups, help establish the normal range of the bio-
logical community as it would exist in unimpaired systems.
Ohio combines narrative and numeric biocriteria and uses fish and in-
vertebrates in its stream and river evaluation programs. Its numeric
biocriteria are defined by fish community measurements, such as the
Index of WeU-Being (IWB) and the Index of Biotic Integrity (IBI). Ohio also
employs an Invertebrate Community Index (ICI). All three measures pro-
vide discrete numeric values that can be used as biocriteria.
Ohio's numeric criteria for use designations in warmwater habitats are
based on multiple measures of fish and benthic macroinvertebrates in dif-
ferent reference sites within the same ecoregion. Macroinvertebrates are
animals without backbones that are large enough to by seen by the un-
aided eye and caught in a U.S. Standard No. 30 sieve. Criteria for this use
designation are set at the 25th percentile of each biological index score re-
corded from the established reference sites within the ecoregion. Excep-
tional warmwater habitat criteria are set at the 75th percentile from the
statewide set of reference sites (Ohio Environ. Prol. Agency, 1987). Use of
the 25th and 75th percentiles, respectively, portrays the minimum biologi-
cal community performance described by the narrative use designations.
Such applications require an extensive database and multiple reference
areas across the stream and river sizes represented within each ecoregion.
To develop the most broadly applicable numeric biological criteria,
careful assessments of biota in multiple reference sites should be con-
ducted (Hughes et al. 1986). The status of the biota in surface waters may
-------
iniroaucvon
be assessed in numerous ways. No smgle index or measure is universally
recognized as free from bias. Evaluating the strengths and weaknesses of
different assessment approaches is important, and a multimetric approach
that incorporates information on species richness, trophic composition,
abundance or biomass, and organism condition is recommended (see
Chapter 6). : '
Other Biocriteria Reference Documents
Based on state interest in having EPA guidance (U.S. Environ. Prot.
Agency, 1987a), program and technical guidance documents for imple-
menting biooiteria have been developed. The biocriteria program guid-
ance document discusses program development issues including
legislative authority, steps in developing biocriteria, and the application of
biocriteria to surface water management (U.S. Environ. Prot Agency,
1990).
A survey of existing state programs; was conducted to delineate the
status of bioassessment implementation on a national basis (U.S. Environ.
Prot. Agency, 1991a). In addition, a reference guide to the technical litera-
ture pertaining to biocriteria has also been developed to provide support
to the program guidance document (U.S. Environ. Prot. Agency, ,1991b).
This reference guide contains cross-references to technical papers that
present concepts, approaches, and procedures necessary to implement
habitat assessment and biological surveys in the development and use of
biocriteria. In December 1990, a symposium on biological criteria was held
to provide a forum for discussing technical issues and guidance for the
various waterbody types of the national surface waters. The proceedings
from this conference are presented in U.S. Environ. Prot. Agency (1991d).
Most recently, the agency has developed guidance to help states initiate
narrative biological criteria (Gibson, 1992).
Suggested Readings
Gibson, George. 1992. Procedures for Initiating Narrative Biological Criteria. EPA-822-B-
92-002. U,S. Environ. Prot Agency, Washington, DC.
U.S. Environmental Protection Agency. 1987a. Report of the National Workshop on In-
stream Biological Monitoring and Criteria. In-stream Biol. Criteria Comm. Reg. 5,
Environ. Res. Lab., Off. Water Reg. Stand., Corvallis, OR.
— . 1987b. Surface Water Monitoring: A Framework for Change. Off. Water, Off. Pol.
Plann. EvaL, Washington, DC.
—:—-. 1991a. Biological Criteria: State Development and Implementation Efforts. EPA
440/5-91-003. Off. Water, Washington, DC.
. 1991b. Biological Criteria: Guide to Technical Literature. EPA 440/5-91^004. Off.
Water, Washington, DC.
—'• . 1991c. Technical Support Document foir Water Quality-based Toxics Control.
EPA 505/2-90-001. Off. Water, Washington, DC
. 1991d. Biological Criteria: Research and Regulation. EPA 440/5-91-005. Off.
Water, Washington, DC.
To develop numeric
biocriteria, the
resident biota are
sampled at minimally
impaired sites to
establish reference
conditions. Attributes
of the biota such as
species richness,
presence or absence
of indicator taxa, and
distribution of trophic
groups are useful for
establishing the
normal range of
biological community
components as they
would exist in
unimpaired systems.
-------
-------
CHAPTER 2.
Components of
Biocriteria
Water resource legislation is designed to protect water resources and
to ensure, their availability to present and future generations. Over
the past two decades, legislative and regulatory programs have estab-
lished goals such as fishable and swlmmable, antidegradation, no net loss,
and zero discharge (of pollutants). Unfortunately, those goals are not eas^
ily translated into actions that accomplish the mandate of restoring and
maintaining biological integrity. The purpose of this chapter is to provide
managers with a basic conceptual understanding of the relationship be-
tween biological integrity and biocriteria and to describe more fully the
biocriteria process.
Conceptual Framework and Underlying Theory
Biological integrity was first explicitly included in water resource legisla-
tion in the Water Pollution Control Act Amendments of 1972 (Pub. L. 92-
500); and the concept, which was retained in subsequent revisions of that
act, is now an integral component of water resource programs at state and
federal levels (U.S. Environ. Prot. Agency, 1990).
The goal of biological integrity, unlike fishable and swimmable goals,
encompasses all factors affecting the ecosystem. Karr and Dudley (1981;
following Frey [1975]) define biological integrity as "the capability of sup-
porting and maintaining a balanced, integrated, adaptive community of
organisms having a species composition, diversity, and functional organi-
zation comparable to that of the natural habitat of the region." That is, a
site with high biological integrity will have had little or no influence from
human society.
Edwards and Ryder (1990) recently used the phrase "harmonic com-
munity" in a similar context to describe the goal of restoring ecological
health to the Laurentian Great Lakes. The sum of balanced, integrated, and
adaptive chemical, physical, and biological data can be equated with eco-
logical integrity (Karr and Dudley, 1981). Such healthy ecological systems
are more likely to withstand disturbances imposed by natural environ-
mental phenomena and the many disruptions induced by human society.
These systems require minimal external support from management (Karr
etal. 1986).,
Purpose:
To provide managers
with a basic
conceptual
understanding of the
relationship between
biological integrity
and biocriteria, and to
describe more fully
the biocriteria process.
-------
3IULOGICAL
Technical Guidance for Streams and Small Rivers
It is important to
distinguish between
the attributes of
natural systems that
we intend to protect
(assessment
endpoints) and the
attributes that we can
measure
(measurement
endpoints). Success
in protecting
biological integrity :
depends on the
development of
measurement
endpoints that are
highly correlated with
assessment
endpoints.
The adjective "pristine" is often invoked in such discussions; however,
in the late 20th century, it is almost impossible to find an area that is com-
pletely untouched by human actions. Thus, the phrase "minimally im-
paired" is more appropriate than the word "pristine" for describing
conditions expected at sites exhibiting high biological integrity.
Degradation of water resources comes from pollution, which is de-
fined in the Clean Water Quality Act of 1987 as "manmade or man-in-
duced alteration of the chemical, physical, biological or radiological
integrity of water" (U.S. Gov. Print. Off. 1988). This comprehensive defini-
tion does not limit societal concern to chemical contamination. It includes
any human action or result of human action that degrades water re-
sources. Humans may degrade or pollute, water resources by chemical
contamination or by alteration of aquatic habitats; they may pollute by
withdrawing water for irrigation, by overharvesting fish, or by introduc-
ing exotic species that alter the resident aquatic biota. The biota of streams,
rivers, lakes, and estuaries, unlike other attributes of the water resource
(e.g., water chemistry), are sensitive to all forms of pollution. Thus, the de-
velopment of biological criteria is essential to the protection of the integ-
rity of water resources.
Components of Biological Integrity
While these definitions establish broad biological goals to supplement
more narrowly defined chemical criteria, their use depends on the devel-
opment of ecologically rigorous biological criteria. The challenge is to de-
fine biological integrity dearly, identify its components, and develop
methods to evaluate a water resource and its surrounding environment
based on the condition of these various components.
Evaluating the elements or components of biological integrity will in-
volve direct or indirect evaluations of biotic attributes. Indirect evaluations
are appropriate if direct approaches are prohibitively expensive or in other
ways difficult to implement It is. important to distinguish between assess-
ment and measurement endpoints. Attributes of natural systems that we
intend to protect for example, the health of a fish population, are assess-
ment endpoints; and attributes that we can measure, for example, age and
size classes of the fish population, are measurement endpoints. Success in
protecting biological integrity depends on the development of measure-
ment endpoints that are highly correlated with assessment endpoints.
Important components of biotic integrity have been measured before.
Toxicologjsts have long recognized the importance of individual health in
evaluating the extent to which human actions have degraded a water re-
source, and ecologists have long used the kinds and relative abundances
of species as indicators of condition. More recently, and in many ways less
insightfully, theoretical measures of diversity have been used to assess
species richness, that is, to determine if the number ,of species or relative
abundances of species have been altered. Fish biologists, for example, use
a variety of measures to assess the health of populations of targeted spe-
cies, such as game fish. However, none of the attributes used in the past
are comprehensive enough to cover all components of biological integrity.
In recent years, a broader conceptual foundation has been developed
to convey the breadth of biotic integrity. The original Index of Biotic Integ-
rity (IBI) consisted of 12 metrics or attributes in three major groups: spe-
-------
... ' CHAPT£r12: .
Components of Biocriterta
ties richness and composition, trophic structure, fish abundance and con-
dition (Karr, 1981). Another way of describing bidtic integrity contrasts the
elements of the biosphere with the processes but argues that both are es-
sential to the protection of biological integrity (Table 2-1). The most obvi-
ous elements are the species of the biota, but additional critical elements
include the gene pool among those species, the assemblages, and land-
scapes.
Table 2-1 .—Components of biological Integrity.
ELEMENTS
PROClESaiS
Genetics
Mutation, recombination
Individual
Metabolism, growth, reproduction
Population/species
Ago specific birth and death rates
Evolulton/spea'attoJi
Assemblage (community
and ecosystem)
Interspecific interactions
Energy flow
Landscape
Water cycle
Nutrient cycles
Repetition sources and sinks
Migration and dispersal
Modified from.Karr, 1990.
Processes (or functional relationships) span the hierarchy of biological
organization from individuals (metabolism) to populations (reproduction,
recruitment, dispersal, spectation) and communities or ecosystems (nutri-
ent cycling, interspecific interaction!}, energy flow). For example, an im-
portant process in streams is an interaction of fish and mussels in which
larval stages of the mussel (glochidia) attach to fish gills, presumably to
enhance dispersal and to avoid predation.
. Other approaches are available, but the important issue here is not
which classification is the best approach. Rather, efforts to assess biological
integrity must be broadly based to cover as many components as possible.
The challenge in implementing biocriteria is to develop reliable and
cost-effective ways to exploit the insight available through biological
analyses. It is, for example, not necessary to sample the entire biota.
Rather, carefully selected representative taxa should be sampled. The
selection of attributes to be used to develop integrative biological criteria
should combine as many attributes as possible with precision and sam-
pling efficiency, but not all elements and processes are directly covered in
standard biological sampling.
Recent efforts to develop integrative approaches include the IBI first
proposed by Karr (1981) and later expanded to apply to a wide geographic
area (Ohio Environ. Prot. Agency, 1987; Lyons, 1992; Oberdorff and
Hughes, 1992), and to taxa other than fish, for example, benthic inverte-
brate assemblages (Ohio Environ. Pirot Agency, 1987; Plafkin et al. 1989).
The Nebraska Department of Environmental Control (Bazata, 1991) has
proposed indices that combine fish and invertebrate metrics, and the Ohio
Environ. Prot. Agency (1987) has calculated several indices separately (fish
and invertebrates) but uses them in combination to determine use attain-
ment status.
•
Efforts to assess
biological integrity
must be broadly
based to cover as
many components as
possible:
-------
Technical Guidance for Streams ana Small Rivers
The choice of
attributes to be
assessed and
measured is critical to
the success of any
program to monitor
biological conditions.
The 6est approach
to assessing
biological integrity
seems to be an
integrative one that
combines assessment
of the extent to which
either the elements or
the processes of
biological integrity
have been altered;
that is, efforts to
protect biotic integrity
should include
evaluation of a broad
diversity of biological
attributes.
Assessing Biological Integrity
A sound monitoring program designed to assess biological integrity
should have several attributes. A firm conceptual foundation broadly
based in ecological principles is essential to a multidimensional assess-
ment that incorporates the elements and processes of biotic integrity. The
use of the concept of a reference condition, a condition against which a site
is evaluated, is also important.
In addition, the general principles of sound project management or
Total Quality Management (TQM>, such as Quality Assurance (QA) and
Quality Control (QQ, are as critical as the use of standard sampling proto-
cols. Quality assurance includes quality control functions and involves a to-
tally integrated program for ensuring the reliability of monitoring and
measurement data; it is the process of management review and oversight
of the planning, implementation, and completion of environmental data
collection activities. Its goal is to assure that the data provided are of the
quality needed and claimed.
Quality control refers to the routine application of procedures for ob-
taining prescribed standards of performance during the monitoring and
measurements process; it focuses on the detailed technical activities
needed to achieve data of the quality specified by the Data Quality Objec-
tives (DQOs). Quality control is implemented at the laboratory or field
level Finally, biological monitoring must go beyond the collection and tab-
ulation of high quality data to the creative analysis and synthesis of infor-
mation about relevant biological attributes.
Numerous attributes of the biota have been used to assess the condi-
tion of water resources. Some are difficult and expensive to measure while
others are not. Some provide reliable evaluations of biological conditions
while others, perhaps because they are highly variable, are more difficult
to interpret Thus, the choice of attributes to be assessed and measured is
critical to the success of any program to monitor biological conditions.
Historically, most biological evaluations were designed to detect a nar-
row range of factors degrading water resources. For example, the biotic
index (Chutter, 1972; Hilsenhoff, 1987) is designed to detect the influence
of oxygen demanding wastes ("organic pollution*) or sedimentation, as is
the Saprobic Index developed early in this century (Kolkwitz and Mars-
son, 1908).
With increased understanding of the complexity of biological systems
and the complex influences of human society on those systems, more in-
tegrative approaches for assessing biological integrity have been devel-
oped. Some (Ulanowicz, 1990; Kay, 1990; Kay and Schneider, in press)
advocate the use of thermodynamics, while others concentrate on richness
or diversity (Wilhm and Dorris, 1968). The best approach seems to be an
integrative one that combines assessment of the extent to which either the
elements or the processes of biological integrity have been altered; that is,
efforts to protect biotic integrity should include evaluation of a broad di-
versity of biological attributes.
Because the goal of biocriteria-bioassessment programs is to evaluate
water resource systems stressed by or potentially destroyed by human ac-
tion, the selection of biological monitoring approaches is critical. Indica-
tors and monitoring design should be structured so that the same
-------
Components ofBiocriferia
monitoring data can serve a multitude of needs. This openness requires a
reasonable level of sophistication for long-term status and trends monitor-
ing. The more complicated the water resource problem, the larger the
number of attributes that should be measured. Finally, programs to moni-
tor the effects of human activity on the environment should have espe-
cially broad perspectives to ensure sensitivity to all forms of degradation.
Complex Nature of Anthropogenic Impacts
The number of human activities that strain the integrity of water resource
systems is huge, and their cumulative impacts create even greater com-
plexity. Thus, it is useful, perhaps even necessary, to develop an organiza-
tional framework within which factors responsible for degradation in
biotic integrity can be evaluated.
A major weakness of past approaches to protect water resources has
been a narrow perspective on the factors responsible for degradation. Spe-
cifically, past approaches focused on reducing the chemical contamination
of the water on the assumption that dean water would produce high qual-
ity water resources. Overall, the determinants of the biological integrity of
the water resource are complex, and the simplistic approach of making
water cleaner, though important is inadequate.
Biological monitoring and the use of biocriteria to assess biotic integ-
rity provides a more comprehensive evaluation of the status of the re*;
source. Such evaluations enhance our ability to identify the factors
responsible for degradation and to treat the problem in the most cost-effec-
tive manner. Monitoring specific and ambient (background) conditions of-
fers unique opportunities to detect, analyze, and plan the treatment of
degraded resources. .
Because human actions may degrade a wider range of water resource
attributes than water chemistry alone, a broader framework is necessary to
identify and reverse the specific factoirs responsible for the degradation of
biotic integrity. Degradation may begin in an area of the watershed or
catchment that is external to the reference or test site simply because it is
often the result of human actions that alter the vegetative cover of the land
surface. These changes combined with the alteration of stream corridors
degrade the quality of water delivered to the stream channels and attack
the structure and dynamics of those channels and their adjacent riparian
environments.
Human activities at the site affect five primary classes of variables —
all of which may result in further degradation of water resources (Karr,
1991). These five internal variables should be placed in a larger context as
illustrated in Figure 2-1:
1. Water Quality: Temperature, turbidity, dissolved oxygen, acidity,
alkalinity, organic and inorganic chemicals; heavy metals, toxic sub-
stances.
2. Habitat Structure: Substrate type, water depth and current velocity,
spatial and temporal complexity of physical habitat.
3. Flow Regime: Water volume, temporal distribution of flows.
-------
TeCnnscal Guicance for Streams and Small Rivers
RpananComdor
EXTERNAL
INTERNAL
Weather/
Climate
Terrestrial
Environment/
Land Use
Biotic
Interactions
Rgure 2-1.—Conceptual model showing the Interrelationship* of the primary vari-
able* relative to the Integrity of an aquatic biota. External refer* to features outside
the stream system; Internal to In-stream feature* (Karr, 1991). Terrestrial environment
Include* factors such a* geology, topography, soil, and vegetation.
4. Energy Source: Type, amount and particle size of organic material
entering stream, seasonal pattern of energy availability.
5. Biotic Interactions: Competition, predation, disease, parasitism,
and mutualism. . *
From this conceptual framework, at least four components of the biota
should be evaluated: structure, composition, individual conditions, and bi-
ological processes (Fig. 2-2). Sample attributes for each component include
the following:
• Community Structure: Species richness, relative abundances,
including the extent to which one or a few species dominates.
• Taxonomic Composition: Identity of the species that make up the
biota. _
• Individual Condition: Health status of individuals in selected
species.
• Biological Processes: Rates of biological activities across the
hierarchy of biology (from genes to landscapes).
Comprehensive assessments of these attributes ensure that all the
components of biotic integrity are protected. For each component, one or
more attributes should be assessed.
Successful metrics represent the expression of a known influence of
human activities on the characteristics of the resident biota. For example,
the presence of few hardy species of fish in abundance may be a response
to sewage in the waters. As human disturbance increases, total species
richness, the number of intolerant species, and the number of trophic spe-
cialists usually decline, while the number of trophic generalists increases.
Generdists are organisms that can use a broad range of habitat or food
types. Exceptions exist: for example, when coldwater streams are warmed,
species richness increases, although this process must be viewed as a deg-
radation of the biotic integrity of a coldwater system.
-------
CHAPTER 2: .
Components of Biocriteria
COIMMTV
otumt
urns
OTMCUCIUTIS
MOOUCIMTV
HAH
BIOLOGICAL ASSESSMENT
2-2.—Organizational structure of the attributes that should OM Incorporated
Into biological assassmmts.
Use of biocriteria to evaluate and protect biotic integrity focuses di-
rectly on the condition of the resource. The development of biological
monitoring is driven by the need for rigorous standardized evaluations of
point and nonpoint source pollution and other circumstances in which the
upstream and downstream approaches to evaluation may be inappropri-
ate. In short, development of biocriteria is driven by the need for a com-
prehensive approach to the study and remediation of the effects of human
interference on water quality.
The Biocriteria Development Process
Biocriteria must be developed with a clear understanding of several im-
portant concepts. Foremost is the basic premise underlying biocriteria de-
velopment: understanding the condition of the biota in a given waterbody
provides a baseline for an integrative and sensitive measure of water qual-
ity. Biocriteria are operational narrative or numeric expressions that char-
acterize and, if properly used, protect biological integrity.
Biocriteria can be used to protect biological integrity and to establish
an aquatic life use classification. Following the definition of biocriteria,
field surveys are conducted to determine whether particular sites meet the
biocriteria or whether they have been affected by human activity. This de-
termination is made by comparing the aquatic biota at potentially dis-
turbed sites with minimally impaired reference conditions. Natural events
Understanding the
condition of the biota
in a given waterbody -
provides a baseline
for an integrative and
sensitive measure of
water quality.
-------
Technical Guidance for Streams and Small Rivers
The basic premise,
that biota provide a
sensitive screening
tool for measuring the
condition of a water
resource, depends on
the assumption that
the greater the
anthropogenic impact
in a watershed, the
greater the
impairment of the
water resource.
Once defined,
biocriteria for a
stream or river will
describe the best
attainable condition.
not initiated by or exacerbated by human .actions (e.g., fire, beavers) are
not considered disturbances in this sense.
The basic premise, that biota provide a sensitive screening tool for
measuring the condition of a water resource, depends on the assumption
that the greater the anthropogenic impact in a watershed, the greater the
impairment of the water resource. A corollary is that streams and rivers
not subject to anthropogenic impact contain natural communities of
aquatic organisms that reflect unimpaired conditions. These assumptions
provide the scientific basis for formulating hypotheses about impairments
—' departures from the natural condition result from human disturbances.
Natural disturbances, such as floods or drought; may also affect the
aquatic biota as part of normal ecological processes, and these responses
vary among ecoregions and stream sizes. For example, relatively stable
structure is characteristic of fish communities in the eastern United States
but stability of fish communities in the Great Plains streams may reflect
human disturbance (Bramblett and Fausch, 1991). Molles and Dahm (1991)
provide additional cautions on the need to consider natural events in in-
terpreting data from biological systems. Thus, natural disturbances must
be considered when interpreting data, but they are not considered as im-
pairments because they are not the result of human activity.
Ideally, biocriteria are reflective of the natural biological integrity of the
particular region under study, that is, of the region as it would be had it not
become impaired. Depending on the resolving capability of the biosurvey
method, the degree of impairment can often be established as part of the
biocriteria development process. Once defined, biocriteria for a stream or
river will describe the best attainable condition. The best attainable condi-
tions represent expected conditions and are directly compared to the ob-
served conditions. Each state needs to formulate appropriate definitive
descriptors (i.e., biocriteria) for the aquatic organisms in its streams, and
these descriptors or biocriteria should support the state's designated use
classifications or other resource protection and management objectives.
Successful implementation of biocriteria requires a systematic pro-
gram to collect and evaluate complex scientific information and translate
that information into an effective planning tool to protect water resources.
This effort must be systematic as well as conceptually and scientifically
rigorous; it must also be logical and easily understood. The components of
a program to implement biocriteria may be divided in a variety of ways.
The four primary steps to develop and implement biocriteria are intro-
duced here and will be discussed in greater detail in later sections of this
document. The four steps are
1. Planning the biocriteria development process.
2. Designating the reference condition for biosurvey sites.
3. Performing the biosurveys to characterize reference condition.
4. Establishing biocriteria based on reference biosurvey results.
Each step must be considered in the context of regulatory policy, the
scientific method, and the practical aspects of fieldwork involving
biosurveys. Further, acceptable biocriteria for streams and rivers can be
-------
CHAPTER^:
Components of Biocriteria
developed in various ways. Therefore, biooiteria development should'be
based on a set of flexible procedures derived from management, the regu-
latory process, or both. When properly implemented, the procedures lead
to self-defined biocriteria that are protective of the unique characteristics
of streams and rivers. When not properly implemented, water resources
continue to be degraded. Although the general concepts and procedures of
biocriteria development can be adapted to any stream or river, the devel-
opment of useful biocriteria requires individual planning for different
waterbodies.
• Planning Biocriteria. Planning includes the classification of surface
water types and the definition of designated uses; however, the planning
process necessarily extends beyond stream and river use classification. To
be effective, planning must ensure that program objectives are clearly de-
fined and that the scientific information generated to meet program objec-
tives is appropriate for making environmental management decisions.
The planning phase assumes the interaction of environmental manag-
ers (staff involved in policy, budgeting, and resource management) and
technical staff (those involved in data, collection and interpretation) to en-
sure that the environmental data to be collected are acceptable and meet
state needs. To ensure this interaction, a formal quality assurance and
quality control plan that includes the formulation of data quality objec-
tives should be considered when implementing the biocriteria develop-
ment process. Complete data quality objectives describe the decisions to
be made, the data required and why, the calculations in which the data
will be used, and time and resource constraints, they are used to design
data collection plans and to specify levels of uncertainty. Levels of uncer-
tainty pertain to the confidence, or lack of confidence, that decision mak-
ers can realistically have that the collected data will actually support
particular conclusions.
Finally, interagency cooperation ('within and among states) should be a
critical component of the planning process. Time spent on developing
good relations with other groups improves biocriteria and their use.
• Designating Reference Condition. Designating the reference condition
for biosurvey sites is the second major activity in biocriteria development
This continuation of the planning process shifts attention to the specific
data needed to define the expectations for the biotic conditions that would
be expected to occur in the study stream in the absence of human impact.
Issues requiring consideration at this stage of the process include
• the database to be formed and evaluated (e.g., the taxonomic
assemblages or other biological attributes to be used to describe
biological condition);
/
• the habitat types to be included in the survey (e.g., runs, riffles,
pools, and snags);
• the type of reference conditions needed for the program or study
being formulated (e.g., regional, ecoregional, or site-specific);
• the geographical scale to which the biocriteria are applicable (e.g.,
specific river reach, watershed, ecoregion, or other parameters);
The development of
useful biocriteria
requires individual
planning for different
waterbodies.
Planning must
ensure that program
objectives are clearly
defined and that the
scientific information
generated to meet
program objectives is
appropriate for
making environmental
management
decisions.
Interagency
cooperation should
be a critical
component of the
planning process.
-------
BIOLOGICAL CRITERIA:
Technical Guidance for Streams and Small Rivers
Definition of the *
reference condition is
a critical step in the
process.
u the temporal scale for which biocriteria are being considered (e.g.,
seasonal, annual, or multiyear);
* how habitat will be assessed to ensure comparability between the
reference condition and the habitat at the reference site before
human impacts; .
• parameters and methods of measurement; and
• how data from the biosurvey are to be evaluated.
Data management, analysis, and reporting requirements should also.
be stipulated and planned for prior to initiating field work. Specific infor-
mation dealing with the designation of reference condition and biosurvey
sites is provided in Chapter 3 of this document.
Because knowledge of biological communities and habitats surround-
ing the surface waters of the study region is essential to effective biological
monitoring, definition of the reference condition Is & critical step in the
process. Careful designation of reference conditions and execution of
biosurveys can reduce the likelihood of problems and minimize the costs
associated with fieldwork.
Knowledge of reference condition may derive from historical data or
from pilot studies of local or regional sites that are relatively undisturbed.
Macroinvertebrate and fish assemblage data have often been routinely col-
lected by state fish and wildlife agencies, water quality agencies, universi-
ties, and others responsible for stream management Although these
historical databases are often overlooked in environmental evaluations,
they can be valuable sources of information. An estimation of biological
integrity at a minimally impaired site may be accomplished by reviewing
existing data and publications for specific streams and rivers. Fausch et aL
(1984) developed fish species richness expectations for several midwestern
streams based on historical data sets. Obviously, the usefulness of histori-
cal data for establishing reference condition is dependent on the original
objective of the data collection effort the collection methods, and the qual-
ity of the data. Even if historical data are inadequate for direct use in des-
ignating the reference condition, they may provide substantial insight
about preexisting conditions at the test or study sites.
• Performing Biosurveys. Performance of the actual biosurvey to charac-
terize the reference condition entails several activities. Often, a presurvey
(pilot study) is necessary to finalize the study plan and the actual logistics
of the fieldwork. Upon completion of the study plan, technical staff must
be fully briefed regarding the study's objectives, quality assurance and
quality control operations, and methods of data collection and summariza-
tion. At this point, the actual biosurvey may be performed. Biosurveys
may include routine local monitoring, sampling over wide geographic
areas, or special case evaluations at one or a few sites.
• Establishing Biocriteria. After the biosurveys have been completed or
the historical data evaluated, the biological status of the reference condi-
tion is used to help define the biocriteria. Based on the results of the sur-
veys, some refinement of aquatic life use designations may be needed for
particular streams or rivers. After writing the biocriteria, they must under-
go final review and approval by each state and the EPA.
-------
• • '.. LiHAPTe-ri 2:
Components ofBiocrtteria
Certain attributes should be considered when drafting formal biocri-
teria. Ideally, biocriteria should be readily understandable and scientifi-
cally and legally defensible. Further, they should be protective of the most
sensitive element of the designated aquatic life use of streams and rivers
and yet express an attainable condition.
Thus, biocriteria should be used in decision making, not only for rou-
tine management procedures but also for guiding resource policy determi-
nations. For those, decisions to be robust, quality assurance programs must
ensure long-term database management, including data entry, manipula-
tion, and analysis.
Biocriteria provide an initial determination of impairment or attain-
ment. Their use may also help to determine sources and causes of degra-
dation when combined with survey information and knowledge of how
organisms react to different stresses (e.g., sight-feeding fish decline when
turbidity increases; tolerant specie!} increase with nutrient enrichment
anomalies of 40 to 60 percent occur only in the presence of complex toxic
effluents and impacts). These response signatures are vital to the success-
ful use of biocriteria to attain water resource protection.
The endpoint of water resource-protection using biocriteria is broader
than clean water. The endpoint of biocriteria and water resource legisla-
tion is "to restore and maintain the physical, chemical and biological in-
tegrity of the nation's waters.*
Suggested Readings
Davies, SP., L. Tsomides, D.L. Courtemandtv and F. Drummond. 1991. Biological Moni-
toring and Biocriteria Development Prog. Sum. Maine Dep. Environ. Prot, Au-
gusta, ME.
Gallant; A.L. et aL 1989. Regtonalization as a Tool for Managing Environmental Re-
sources. EPA/600/3-89.060. US. Environ. Profe Agency, Environ. Res. Lab.,
Corvaffls, OR. . , ' •
Karr, JJL 1991. Biological integrity: A long-neglected aspect of water resource manage-
ment Ecol. Appl. 1:66-84.
North Carolina Department of Environmental Health and Natural Resources. 1990.
Standard Operating Procedures, Biological Monitoring. Environ. Sci. Branch, Eco-
systems Analysis Unit, Biol. Assess. Group, Div. Environ. Manage., Water Qual.
Sec., Raleigh, N.C ,
Ohio Environmental Protection Agency. 1987. Biological Criteria for the Protection of
Aquatic Life. In The Role of Biological; Data in Water Quality Assessment Vol. 1.
Div. Water QuaL Monitor. Assess., Surface Water Sec, Columbus, OH.
— . 1990. The Use of Biocriteria in the Ohio EPA Surface Water Monitoring and As-
sessment Program. Columbus, OH.
Plafldn, J.L 1989. Water quality-based controls and ecosystem recovery. Pages 87-96 « J.
Cairns Jr., ed. Rehabilitating Damaged Ecosystems. VoL 2. CRC Press, Boca Raton, FL
U.S. Environmental Protection Agency. 1990. Biological Criteria: National Program
Guidance for Surface Waters. EPA-440/5-90-004. Off. Water, Washington, DC
,
Biocriteria should
be readily
understandable and
scientifically and
legally defensible.
Further, they should
be protective of the
most sensitive
designated aquatic
life use of streams
and rivers and yet
express an attainable
condition.
The endpoint of
biocriteria and water
resource legislation is
"to restore and
maintain the physical,
chemical, and
biological integrity of
the nation's waters."
-------
-------
CHAPTERS.
The Reference Condition
The term biocriteria implies the notion of comparison to the highest at-
tainable condition. The reference condition establishes the basis for
making comparisons and for detecting-use impairment; it should be appli-
cable to an individual waterbody, such as a stream segment, but also to
similar waterbodies on a regional scale. The reference condition is a critical
element in the development of a bioaiteria program.
Establishing the Reference Condition
Recognizing that absolutely pristine habitats do not exist (even the most re-
mote lakes and streams are subject to atmospheric deposition), resource man-
agers must agree to accept sites at which minimal impacts exist or are
achievable as the reference condition for a given region. Acceptable reference
conditions will differ among geographic regions and states because soil con-
ditions, stream morphology, vegetation, and dominant land use differ be-
tween regions. In heavily agricultural, industrial-commercial, or urbanized
regions, undisturbed streams or reaches may not exist and reference condi-
tions may need to be determined based on that which is likely attainable, the
historical record, or other methods of estimation. *
Reference conditions can be established in a variety of ways
through reference sites, historical data, simulation models, or expert con-
sensus.
• Reference Sites. Reference sites refeor to locations in similar waterbodies
and habitat types at which data can be collected for comparison with test
sites. Typical reference sites include sites that are upstream of point
sources; sites in nearby watersheds; sittes that occur along gradients of im-
pact (near field/far field); and reference sites that may be applied to a vari-
ety of test sites in a given area. Sites upstream of point sources may or may
not exhibit the quality of the overall reference condition. However, their
proximity to the site in question makes them a useful qualifier for regional
references, especially in controversial situations.
Achievable biological conditions may be described through a statistical
evaluation that integrates biological attributes from a group of sites that
have the same characteristics and expectations. This approach can be used
to establish attainment criteria for aquatic life'uses and to test the probabil-
ities of membership in the established site (Maine Dec. Environ. Prot.
1993)
Purpose:
To provide guidance
for defining biological
expectations based
on a reference •
condition, and for
making comparisons
to test sites.
The reference
condition establishes
the basis for making
comparisons and for
detecting use
impairment; it should
be applicable to an
individual waterbody,
such as a stream,
segment, but also to
similar waterbodies
on a regional scale.
-------
BIOLOGICAL C
Technical Guidance for Streams and Small Rivers
Reference conditions
can be established in
a variety of ways —
incorporating
reference sites,
historical data,
simulation models, or
expert consensus.
• Historical Data. In some cases, data are available that describe biologi-
cal conditions in the region during the past half century. Careful scrutiny
and evaluation of these data provide insight about the communities that
have been or can be achieved in various waterbody types and may be an
important initial phase in the biocriteria development process. These rec-
ords are usually available in natural history museums, university collec-
tions, and some agencies, such as state water resource agencies and fish
and wildlife, departments; however, some historical biological surveys
were conducted at impaired sites that used inefficient sampling methods,
were insufficiently documented, or had objectives markedly different from
biocriteria determination. Such data are of questionable value for estab-
lishing precise reference conditions and should be used advisedly.
• Simulation Models. Simulation models include mathematical models
(logical constructs following from first principles and assumptions), statis-
tical models (built from observed relationships between variables), or a
combination of the two. The complexity of mathematical models that can
predict reference conditions is potentially unlimited, but as complexity in-
creases, the costs will be higher and some of the model's predictive ability
will biflbst (Peters, 1991). Thus, models that predict biological reference
conditions should only be used as a last resort and with great caution be-
cause they involve complex and untestable hypotheses (Peters, 1991;
Oreskes et al. 1994). Nevertheless, several models that predict water qual-
ity in rivers and reservoirs from first principles of physics and chemistry
have been quite successful (e.g., Kennedy and Walker, 1990). Mathematical
models to predict biological conditions have been less successful and, so
far, not very useful in an assessment or management context.
Statistical models can be fairly simple in formulation, such as the
Vollenweider model and the morphoedaptic index to predict trophic status
(Vbllenweider, 1975; Vighi and Chiaudani, 1985). These models require a
sufficiently large database to develop predictive relationships and, in their
current state of development, predict only nutrient conditions, not the
structure of biological communities
Hybrid models use both first principles and statistical relationships be-
tween variables. Hybrids are typically large simulation models intended to
predict the behavior of a stream over time; they are commonly used to pre-
dict water quality for management (Kennedy and Walker, 1990). Most exist-
ing models predict water quality variables such as chlorophyll a, nutrient
concentrations, Secchi depth, and oxygen demand. Inferring the composi-
tion of biological assemblages from predicted water quality would require
another model relating assemblages to stream water quality.
Model development for biological criteria is still rudimentary. How-
ever, as state databases expand, this tool will become more important and
will likely assume a growing role in establishing reference conditions.
• Expert Opinion/Consensus. When no candidate reference sites are ac-
ceptable, and models are deemed unreliable, then expert consensus is a
necessary alternative to establish reference expectations. Under such cir-
cumstances, the reference condition may be defined using expert opinion
based on sound ecological principles applicable to the region of interest
Three or four skilled biologists are convened for each assemblage used in
-------
: , CHAPTERS:
The Reference Conditicn
the assessment. Each of these experts should be familiar with the streams
of the region and with the assemblage they will judge. They are asked to
develop a description of the assemblage in relatively unimpacted streams
based on their collective experience. The description developed by consen-
sus will be more qualitative than quantitative. This approach is very diffi-
cult, however, because of a plausible diversity of individual interpre-
tations and the added risk of subjective evaluation.
To establish reference conditions, investigators will incorporate any or
,°f *ese techniques/ which are riot necessarily independent of each
other.They can be used mutually to support decisions on reference condi-
tion. However, the use of reference sites to establish conditions is always
preferable because sites represent achievable goals and can be regularly
monitored. Historical data and expert opinion are often used to support
decisions regarding reference sites. Simulation models, that incorporate
historical data or expert opinion are the primary alternative to reference
sites and may be most useful in the assessment of significantly altered
sites or waterbodies unique to the region under study.
The most appropriate approach to establishing reference conditions is
to conduct a preliminary resourcejssessmeht to determine the feasibility
of using reference sites (Fig. 3-1). If reference sites are not acceptable, then
some form of simulation modeling may be the best alternative. This situa-
tion would occur if no "natural" sites exist and "minimally impaired sites-
are unacceptable. Biological attributes can be modeled from neighboring
regional site classes, expert consensus, and/or a composite of "best" eco-
logical information. Such models may be the only viable means of examin-
ing significantly altered systems. The expectations derived from these
models may be regarded as hypothetical or temporary until more realistic
attainment goals can be developed.
The use of reference sites provides the best estimate of present-day at-
tainment conditions. The selection of minimally disturbed sites from a site
class provides the most realistic basis for the expectation that biological
integrity can be attained. In this situation, the central tendency of the bio-
logical measure is a conservative estimate of the expected biological condi-
tion.. Some states, for example, Ohio and Honda, use a lower percentile
(25th percentile) as their threshold for attainment When relatively few
sites are unimpaired and are essentially more than minimally disturbed,
an upper percentile of the range of biological values from all sites may be
the best alternative. An interim expected biological condition can be devel-
oped from this approach.
The Use of Reference Sites
The determination of the reference condition from reference sites is based
on the premise that streams minimally affected by human activity will ex-
hibit biological conditions most natural and attainable for streams in the
region. Anthropogenic effects include all possible human influences, for
example, watershed disturbances, habifcat alteration, nonpoint source run-
off, point source discharges, atmospheric deposition, and angling pres-
sure. The premise does not consider any human activities as
improvements; for example, planting non-native riparian vegetation or
stocking with artificially high abundances of game or non-native fish are
The most
appropriate approach
to establishing
reference conditions
is to conduct a
preliminary resource
assessment to
determine the
feasibility of using
reference sites.
The determination of
the reference
condition from
reference sites is
based on the premise
that streams minimally
affected by human
activity will exhibit
biological conditions
most natural and
attainable for streams
in the region.
-------
3IOLC31CAL CRITERIA,
Technical Guidance for Streams and Small Rivers
Two primary
considerations guide
the selection of
reference sites:
minimal impairment
and
representativeness.
Sites that are
undisturbed by
human activities are "
ideal reference sites.
However, land use
practices and
atmospheric pollution
have so altered the
landscape and quality
of water resources
nationally that truly
undisturbed sites are
rarely available.
PRELIMINARY RESOURCE ASSESSMENT
Reference Sites
No Rota
•are* Sites
Use (1) neighboring
site classes, (2) expert
consensus, or (3)
composite of "best*
Flgur* 3-1.—Approach to establishing reference conditions.
not improvements relative to biological integrity. In practice, most refer-
ence sites will have some of these impacts; however, the selection of refer-
ence sites is made from those with the least anthropogenic influences.
Reference sites must be carefully selected because they will be used as
sources for the biocriteria benchmarks against which test sites will be com-
pared. The conditions at reference sites should represent the best range of
conditions that can be achieved by similar streams within a particular eco-
logical region. The key to making such biocriteria. benchmarks protective
is to organize sites into classes so that the minimum acceptable perfor-
mance is commensurate with the capability of the resource. Therefore, two
primary considerations guide the selection of reference sites within each
class: minimal impairment and representativeness.
• Minimal Impairment Sites that are undisturbed by human activities
are ideal reference sites. However, land use practices and atmospheric pol-
lution have so altered the landscape and quality of water resources nation-
ally, that truly undisturbed sites are rarely available. In fact, it can be
argued that no unimpaired sites exist. Therefore, a criterion of "minimally
impaired" must be used to determine the selection of reference sites. In re-
-------
CHAPTERS:
The Reference Condition
gions where even such minimally impaired sites are significantly de-
graded, the search for suitable sites should be extended over a wider area,
and multistate cooperation may be essential. The purpose of selecting min-
imally impaired sites to represent reference conditions is primarily goal-
setting. Once attainment of these conditions is achieved on a large scale, a
higher criterion is possible. In no instance should any notably degraded
condition be accepted as the reference for criteria development.
• Representativeness. Reference sites must be representative of the
waterbodies under investigation; that is, they must exhibit conditions sim-
ilar to those of other sites in the same region. Sites that contain locally un-
usual environmental factors will result in uncharacteristic biological
conditions and should be avoided.
The overall goal in the establishment of the reference condition from
carefully selected reference sites is to describe the biota that investigators
may expect to find at sites of interest These "test or assessment sites" will
be compared to the reference sites to determine whether impairment ex-
ists. The characteristics of appropriate reference sites vary among regions
qf the country and for different waterbody and habitat types. In general,
the following characteristics (modified from Hughes et aL 1986) are typical
of ideal reference sites:
• Extensive, natural, riparian vegetation representative of the region.
• Representative diversity of substrate materials (fines, gravel, cobbles,
boulders) appropriate to the region.
• Natural channel structures typical of the region (e.g., pools, riffles, runs,
backwaters, and glides).
• Natural hydrograph—in some cases, the flow patterns display large sea-
sonal differences in response to rainfall and snowmelt; in other cases, sta-
ble discharges are typical of water that originates from underground
sources. Biota evolve in the face of natural discharge patterns.
* Banks representative of undisturbed streams in the region (generally cov-
ered by riparian vegetation with little evidence of bank erosion, or under-
cut banks stabilized by root wads). Banks should provide cover for
aquatic biota.
• Natural color and odor — in some regions, clear, cold water is typical of
the waterbody types in the region; in others, the water is turbid or
stained.
• Presence of animals, such as piscivorous birds, mammals, amphibians,
and reptiles, that are representative of the region and derive some sup-
port from aquatic ecosystems.
A single minimally impaired site cannot be truly representative of any
one region or population of sites, and a frequent difficulty is matching up-
stream and downstream habitats for valid comparison. For example, if habi-
tat is degraded upstream but not downstream, the effects of a discharge may
be masked. Reference conditions based on multiple sites are more representa-
tive and form a valid basis for establishingquantitative biocriteria.
One problem in the use of minimally impaired sites as references is
what to do if an area is extensively degraded so that even these sites ihdi-
Therefore, a criterion
of "minimally
impaired" must be
used to determine the
selection of reference
sites.
The overall goal in
the establishment of
the reference
condition from
carefully selected
reference sites is to
describe the biota
that investigators may
expect to find at sites
of interest.
-------
BIOLOGICAL CRITERIA.
Technical Guidance for Streams and Small Rivers
In adjusting the
biocriteria, managers
must strike a balance
between the ideal
restoration of the
water resource and
the fact that human
activity affects the
environment.
The purpose of
classification is to
group similar things
together, that is, to
prevent the
comparison of apples
and oranges.
cate significant deterioration. Many systems are altered through channel-
ization, urbanization, construction of dams and highways, or management
for certain sport fisheries or reservoirs (Karr and Dionne, 1991). The condi-
tion of these systems is a result of societal decisions that have to be taken
into account in the development of biocriteria, but they should not com-
promise the objective of defining the natural state. Biocriteria can be quali-
fied by the assignment of designated uses, but the reference condition
must describe the site as one would expect to find it under natural or min-
imally impaired conditions.
Although the biocriteria established for altered systems serve as a
baseline for judging further degradation, their ultimate goal is to achieve
the sites' recovery to the best attainable condition •— as represented by
conditions at "minimally impaired* sites. Consensus of expert opinion
and historical data play an important role in .characterizing the reference
condition for these systems, as does the application of innovative manage-
ment practices to obtain improvement.
In adjusting the biocriteria, managers must strike a balance between
the ideal restoration of the water resource and the fact that human activity
affects.the environment The most appropriate course of action will use
minimally impaired sites as the maximum amount of degradation that will
be tolerated, thereby ensuring adherence to the antidegradation policy of
the dean Water Act. Continual monitoring should provide the feedback
necessary to make reference site and criteria adjustments as warranted
during the restoration process. .
Characterizing Reference Conditions
Characterization of regional reference conditions for biocriteria develop-
ment consists of the following steps:
1. Classification of the resource. All streams are not alike; therefore,
reference conditions (expectations) will differ among geographic re-
gions and stream types.
2. Selection of the best available sites in each resource class as candi-
date references.
3. Characterization — including confirmation and rfconement of the
reference conditions — based on a biological survey of reference
sites. . '
Classification
The purpose of classification is to group similar things together, that is, to
prevent the comparison of apples and oranges. Meaningful classification is
not arbitrary (an apple is not an orange); professional judgment is invariably
involved to arrive at a workable system that separates dearly different condi-
tions, yet does not consider each waterbody or watershed a special case. By
classifying, we reduce the complexity of biological information. Classification
improves the resolution or sensitivity of biological surveys to detect impair-
ment by partitioning or accounting for variation zimong sites.
-------
CHAPTER 3:
me Reference CcncW/cn
There are two fundamental approaches to classification: a priori and a
posteriori (Conquest et al. 1994). A priori classification is a system based
on preconceived information and theories, for example/ using physio-
graphic provinces to classify streams. The a posteriori approach bases the
classification solely on the data collected and finds classes (e.g., using clus-
ter analysis) within these data.
In operational assessment and management of streams, an assessment
site is assigned to a class (e.g., mountain headwater streams) before it is
actually surveyed and biological data are collected. Ideally, sites should be
assigned to a class from mapped information before any sampling is done.
Therefore, an a priori classification based on maps or other easily obtain-
able secondary information is often developed for characterizing reference
conditions. The biosurvey data are subsequently used to test that classifi-
cation. ,
Stream characteristics that are readily affected by human activities or
occur as a biological response to physical or chemical conditions should
not be used as classification variables. Such responses may include land
use, habitat condition, or nutrient concentrations. For example, in the
southern Rockies ecoregion, riparian zones are heavily forested; and in the
neighboring Arizona/New Mexico Plateau ecoregion, riparian zones are
relatively unvegetated. The classification variable in this case is ecoregion,
and riparian vegetation is a response to ecoregion. If dense riparian vege-
tation were used as a classification variable, we would run the risk of mis-
classifying an unimpaired, unvegetated stream in the Arizona/New
Mexico Plateau as impaired by comparison to natural, streams in the
southern Rockies. This example shows that the best classification variables
are those that are readily obtained from maps or regional water character-
istics^ such as, ecoregion, gradient, alkalinity, and hardness.
Framework for Preliminary Classification
The intent of this protocol is not to develop a classification scheme appli-
cable to the entire United States. Classification must be regional in scope
and must use regional expertise to determine which variables are useful in
a region.
Classification should be parsimonious to avoid proliferation of classes
that do not contribute to assessment
"•• .'.-''
Ecoregions
Biologists have long noted that assemblages and communities can be clas-
sified according to distinct geographical patterns (e.g., Wallace, 1869; Mac-
Arthur, 1972). We observe areas of the country within which types of
ecosystems and their attributes are consistent and similar when compared
to those of other areas. The recognition of such patterns occurs at various
levels: global, continental, regional, and locaL
Regionalization identifies natural spatial patterns. It accounts for spa-
tial variation by partitioning the landscape into smaller areas of greater
homogeneity. Ecological regkmalization (as one type of regjonalization) re-
sults in a map of ecological regions, or ecoregions. Such maps bring spatial
organization to ecological variability. They are useful in a variety of ways,
for example, to summarize the condition of resources in a particular area,
The intent of this
protocol is not to
develops
classification scheme
applicable to the
entire United States.
Classification must be
regional in scope and
must use regional
expertise to
determine which
variables are useful in
a region.
-------
3!CLOGICAL CRITERIA.
Tetnnical Guidance for Streams ana Small Rivers
The basic goal of
regionalization is to
depict areas of
ecological
homogeneity relative
to other areas.
One advantage of
having a consistent
framework is that
states that share the
same ecoregion can
cooperate across •
political boundaries.
In times of limited
resources, such
cooperation makes
financial as well as
scientific sense.
to identify potential or achievable ecological conditions (e.g., regionally
achievable biooiteria), to characterize typical impact types and impair-
ments/to develop protective and remedial procedures that are tailored to
unique regional characteristics, and to present scenarios of realistically
achievable ecological conditions in particular regions (Gallant et aL 1989;
Hughes etal. 1990; Omernik and Gallant, 1990).
The basic goal of regionalization is to depict areas of ecological homo-
geneity relative to other areas. Fenneinan (1946) defined physiographic
provinces within which the physical characteristics of the landscape, such
as surface relief and slope, were homogenous relative to other areas..
Kuchler (1964) identified regions of similar potential natural vegetation.
Ecological regionalization should take into account all pertinent avail-
able information in the depiction of regions, at whatever scale the regions
are to be defined (Omernik, 1987). Primary categories of information used
in the process are (1) factors that control spatial patterns, such as climate,
topography, and mineral availability (soils, geology); and (2) factors that
respond to or integrate these controlling factors/ such as vegetation and
land use. Both sets of categories and each factor within them must be
judged for their usefulness in depicting regions. In some areas, one combi-
nation^ factors may be more useful than another for detecting regional
patterns, and care must be taken to select the right combination each time.
The complex interplay among the various factors must also be considered.
Omernik's approach to defining ecoregions grew out of an effort to
classify streams for more effective water quality.management Thus, it is
one of the few ecological frameworks expressly intended for water quality
assessment. In examining spatial patterns of stream quality data, it became
clear that neither major land resource areas nor Bailey's ecoregions were
adequate (Hughes and Omernik, 1981; Omernik, 1987; Omernik et al.
1982). Hydrologic unit classifications have also been used as a framework
for water quality assessments, and drainage basins influence fish distribu-
tions, but the spatial differences in the quantity and quality of aquatic re-
sources usually correspond more to ecoregions than to topographic
divides (Omernik and Griffith, 1991).
Ecoregions have been used successfully to stratify the biotic character-
istics of streams in Arkansas (Rohm et aL 1987), Nebraska (Bazata, 1991),
Ohio (Larsen et al. 1986), Oregon (Hughes et al. 1987; Whittier et al. 1988),
Wisconsin (Lyons, 1989), and the region of the Appalachians (Gerritsen et
al. 1993). Arkansas, Minnesota, and Ohio use the ecoregion/ biocriteria ap-
proach in their standards program; and several other states, such as Flor-
ida, Mississippi, Alabama, Idaho, Montana, Oregon, Washington, and
Iowa, are evaluating the advantages of using ecoregions for biological as-
sessments.
One advantage of having a consistent framework is that states that
share the same ecoregion can cooperate across political boundaries. In
times of limited resources, such cooperation makes financial as well as sci-
entific sense. Where ecoregional biological criteria and use designations
have been tested, they have proven to be cost-effective and protective tools
(Hughes, 1989). EPA's Science Advisory Board (SAB) has concluded that
the ecoregion concept "is superior to the classification methods that are
currently used by most environmental managers" (U.S. Environ. Prot.
Agency, 1991e).
-------
CHAPTERS:
The Reference Condition
Careful review of the purposes for regionalization and selection of the
appropriate regional framework is an important part of the development
of biocriteria. It may also be necessary to increase the resolution of existing
regional frameworks by defining separate regions or subregions. Tech-
niques for this process are described in the references listed in this docu-
ment, particularly in Omemik's studies and Iffrig and Bowles's
compendium of regional frameworks (1993).
Watersheds
Watersheds are a spatial organizing unit that can be used to develop
biocntena; however, watershed boundaries' are not inconsistent with
ecoregions. Increasing attention has been focused on reorienting water
quality management programs to operate basinwide oh a more compre-
hensive, coordinated basis, rather than within strict programmatic bound-
ane« as has been the norm. EPA's Watershed Protection Approach (U.S.
Environ. Prot AgTency, 1991f; 1993) is intended to encourage states to move
in the direction of basinwide water quality management. The basinwide
approach provides a framework within which to design an optimal mix of
water quality management strategies. By integrating and coordinating
across program and agency boundaries, basinwide management teams can
implement integrated solutions using limited resources. Thus they can ad-
dress the most significant water quality problems without losing sight of
other factors contributing to the degradation of the resource. Integration
through the basinwide approach helps managers achieve the short- and
long-term goals for the basin by allowing the application of resources in a
timely and geographically targeted manner.
Basinwide management, as designed and implemented by states and
EPA, contains certain features that make it an achievable element of the
biocnteria process:
• River Basin Management Units. The state is divided into large-scale
basins that provide unique units for management. All program activities
that can be facilitated by or that affect basinwide management are coordi-
nated. For instance, data requirements are aggregated and incorporated
within monitoring plans, interpretations are pooled to arrive at overall as-
sessments, and management recommendations are the result of collabora-
tion (e.g., teams of modelers, permit writers, biologists, hydrologists,
planners, engineers).. ^
• Geographic Risk-based Targeting. Because all states have limited re-
sources and are not able to assess and solve every problem in a watershed,
basin management frameworks establish a set of criteria for targeting efforts
to solve the most important problems in a given area. These problems may
include risks to water quality, aquatic life, or human health. While every
basin in a state is visited during a basin management cycle, some waters
within and across basins receive a great deal more attention than others.
• Direct Link to Regionalization. An important feature of the basin man-
agement approach is its ability to incorporate a nested hierarchy of hydro-
logic units. Minshall (1993) discusses the need to assess ecological
condition in streams and rivers within a hierarchical landscape-scale
Careful review of the
purposes for
regionalization and
selection of the
appropriate regional
framework is an
important part of the
development of
biocriteria. It may also
be necessary to
increase the
resolution of existing
regional frameworks
by defining separate
regions or subregions.
-------
BIOLOGICAL CRITERIA:
Technical Guidance for Streams and Small Rivers
-------
approach. FnsseU et al. (1986) present a hierarchical framework for classi-
fying stream habitat within an overall watershed perspective. Their frame-
work 1S designed so that the class of any particular system is partially
determined by the class of the higher-level system of which it is a compc-
nent. , -,r
_ At the broadest scale of organization, Frissell et aL (1986) recognized
stream systems (1.6., watersheds), followed in order of increasing spTtial
resolution (and decreasing spatial extent) by segment, reach, pool or riffle,
and microhabitat systems. Minshall (1993) extends the uppeVend of this
classification scheme to include biogeodimatic regions, £. providing^
direct connection to ecoregions; and Gregory et aL (1991) similarly discuss
the ecosystem attributes of riparian zones. «»"«».
Table 3-1 summarizes the Frissell et al. (1986) classification framework
as modified by Minshall (1993). Initial stratification of sites by
r0?0^*1? rc8i0nS Can * Perfonned using ecoregion delineation (Om-
erruk, 1987). Incorporation of flow information using procedures of Poff
and Ward (1989) provides further refinement of this scale of stratification
and includes explicit recognition of flow as a major environmental deter-
(Minshall, 1993; Rabeni and
Ecoregions are the preferred classification for establishing reference ex-
pectations in watersheds because biota and biotic metrics respond to
ecoregional differences. Ecoregional stream systems are defined primarily
by local conditions of climate, geology, topography, and terrestrial vegeta-
tion. Three examples of ecoregions are sufficient to illustrate biological
variability: • • .. ' '
1. The Calapooia River watershed (Fig. 3-2) in western Oregon crosses
three ecoregions: the Willamette Valley plains; the transitional foot-
rcKm^"'!.""?. ** Westem Cascades (Omemik and Griffith,
1991). Fan, benthic macroinvertebrates, and chemical and physical
habitat from 17 sites along the length of the watershed were sam-
/„••«:
—.—/0\.
• liiimiii viiiir
• I'ill Cntl
O Itstir* Cltcffls
O tlltm CIICKII
Figure 3-2.--Reclprocal averaging ordination of sites by fish
,aTh!dl °reflr ' ^ lnS8t
in the rivers and ecoregions.
the Calapooia
.. CHAPTERS:
The Reference Condition
Ecoregions are the
preferred
classification for
establishing reference
expectations in
watersheds because
biota and biotic
-metrics respond to
ecoregional
differences.
-------
Technical Guidance (or Streams and Small Rivers
Acceptable
reference sites will
differ among
geographic regions
and states because
soil conditions,
stream morphology,
physiography,
vegetation, and
dominant land uses
differ between regions.
pled to assess changes in the river as it passed through these
ecoregions. The presumption was that similar biological communi-
ties would be found in areas of similar habitat, and that variation
would correspond to observable patterns of change in the terrestrial
features of the watershed.
The study results indicate that imposing an ecoregions frame-
work on the watershed delineation is a useful predictor of stream
reaches having similar biological communities. Although there was
change in the communities along the watershed, distinct assem-
blages could be identified corresponding to the separate ecoregions
within the Calapooia River watershed.
2. Ohio consists of two hydrograpnic basins, a Lake Erie drainage and
an Ohio River drainage. Hydrograpnic boundaries restrict fish dis-
persal, and there are minor faunal differences between the two ba-
sins (Ohio Environ. Prot. Agency, 1987; Yoder, 1991). Ohio also
includes parts of five ecoregions, and ecoregional differences ac-
count for a substantial amount of the variance in fish metrics and in
the index of biotic integrity (IBI). Two ecoregions straddle the di-
- -vide between the basins, one is entirely in the Lake Erie drainage,
and two are entirely in the Ohio River drainage. If there are major
differences between drainage basins, then the ecoregions that strad-
dle the basins should be more variable. However, variability of IBI
scores in all five ecoregions is similar, showing that drainage basins
are negligible compared to ecoregions for explaining biological
variability.
3. Florida comprises two major drainages, the Gulf of Mexico and the
Atlantic Ocean. Examination of invertebrate metrics at reference
sites in Florida reveal three ecoregional classes: northwest Florida
(the Florida panhandle); peninsular Florida, and northeast Florida
(EA, Inc., and Tetra Tech, Inc., 1994). Peninsular and northeast Flor-
ida both straddle the divide between the Atlantic and Gulf drain-
ages; yet there are no major differences in metric values between
Atlantic and Gulf basin sites on the Florida peninsula, and the pen-
insula differs markedly from the panhandle region, which is in the
Gulf drainage.
Biogeographic differences between watersheds can be important when
the watersheds are separated by a major, largely impenetrable barrier,
such as the Continental Divide. Drainage dividers in more level terrain ap-
parently do not cause significant differences in reference expectations.
Implementation of biocriteria, as noted earlier, is best accomplished
through an ecoregionalization approach. The implications of this with re-
spect to states that are developing basinwide management approaches is
that there may be a set of reference conditions and biocriteria established
for each of the separate ecoregjon areas within a given basin. Ecoregional
reference conditions arid biocriteria will likely be transferable across basins
in a given state and — to the extent .that ecoregions cross state boundaries
— across states. This will enhance the ability of adjacent states to develop
coordinated basinwide management plans for interstate basins by provid-
ing a common set of reference conditions and data to be applied in the cor-
responding ecoregions.
-------
The Reference Condition
Site Selection ,
Because absolutely pristine habitats do not exist, resource managers must,
as previously rioted, decide what level of disturbance is acceptable in the
area that represents an achievable or existing reference condition. That is, a
critical element in establishing reference conditions is deciding how to de-
termine that a site is only 'minimally impaired.' How much degradation
can be allowed? Acceptable reference sites will differ among geographic
regions and states because soil conditions, stream morphology, physio-
graphy, vegetation, and dominant land uses differ between regions.
The selection of representative and minimally impaired reference sites
involves qualitative and quantitative information based on past experience
and potential disturbances in regional streams. Factors that should be con-
sidered in a preliminary selection, in approximate order of importance, in-
clude the following:
1. Drainage wholly within the ecoregion of interest
2. No upstream impoundments.
3. No known discharges (NFDES) or contaminants in place.
4. No known spills or other pollution incidents.
5. Low human population density.
6. Low agricultural activity.
7. Low road and highway density.
8. Drainage on public lands.
9. Minimal nonpoint source problems (agriculture, urban, logging,
mining, feedlots, acidic deposition).
10. No known intensive fish stocking (e.g., put-and-take stocking) or
other management activities that would substantially shift the
community composition.
In most settled regions of the country, reference sites will be selected
by searching topographic maps for streams with the least human impacts.
If candidate reference sites are more numerous than can be sampled, they
should be selected randomly. Random selection will be especially impor-
tant in regions with large undeveloped or undisturbed areas (e.g., moun-
tainous regions, federal lands). Agricultural and heavily populated regions
— including most of the East, Midwest, and California — will require sub-
jective (nonrandom) reference site selection.
Examples
Montana Reference Conditions .
The Montana Department of'Health' and Environmental Sciences (1990)
has compiled data that describe reference conditions. Thirty-eight streams
were proportionally allocated among six ecoregions in Montana, and the
following criteria were used to determine a set of candidate reference-
streams. ,
1. Most or all of the drainage basin of candidate streams is in the
"most typical" area of the ecoregion.
In most settled
regions of the country,
reference sites will be
selected by searching
topographic maps for
streams with the least
human impacts.
-------
3ICLOGICAL
Technical Guidance'for Streams and Small Rivers
2. Each ecoregjon includes at least two second-order.streams, two
third-order streams, and two fourth- or fifth-order streams.
3. Reference streams are not water quality limited.
4. The same streams serve as references for proposed Montana
nonpoint source demonstration projects.
5. Reference streams adequately represent the major water use
classifications in each ecoregion.
6. Information is available on the kinds and abundances of fish
. species present in the streams. •
7. Sampling sites have comparable habitat from stream to stream
and are located to minimize human impacts and access problems.
Site selection in the Appalachian Ridge and Valley
Because of differences in dominant land use and amounts of degradation,
neighboring ecoregions may have widely different reference sites and con-
ditions. For example, in the Central Appalachian Ridge and Valley eco-
region~criteria for selecting reference sites differ between the region's
agricultural valley subecoregions and its forested ridge subecoregions
(Gerritsenetal. 1993; Omerniketal. 1992). '
The Ridge and Valley region of the Appalachians consists of sharply
folded sedimentary strata that have eroded, resulting in a washboard-like
relief of resistant ridges alternating with valleys of less-resistant rocks. The
region has been divided into four subecoregions corresponding to ridges
and valleys of different parent material (Omernik et al. 1992):
• Limestone valleys are characterized by calcareous bedrock and predomi-
nantly agricultural land use.
• Shale valleys axe characterized by noncalcaireous bedrock, primarily
shale; and lower intensity agricultural land use. .
• Sandstone ridges are characterized by highly resistant sandstones and
forested land use.
• Shale ridges are characterized by shale bedrock and forested land use.
Each subecoregion imparts characteristic topography, hydrology, and
water chemistry to streams and thus influences biota. The subecoregions
are not continuous but interdigitate throughout the Ridge and Valley.
The least impacted sites occur on the ridges, where land use is pre-
dominantly forested, and where protected lands (e.g., national forests, rec-
reation areas) are common. In contrast, nearly aE streams in the valleys,
and especially in the limestone valleys, are impacted by agriculture, habi-
tat modification, and other nonpoint sources. "Minimally impaired'' is,
therefore, interpreted on a relative, sliding scale in each subecoregion. Ref-
erence sites for the ridges are strictly defined: they are unimpacted except
by atmospheric sources. They have no discharges, nearly complete forest
cover in the drainage, and no recent construction or clearcutting in the
drainage. Reference sites in the valley subecoregions are less strictly de-
fined; that is, the interpretation of minimally impaired is flexible enough '
to allow a sufficient number of reference sites to be selected.
-------
CHAPTERS:
The Reference Condition
Confirmation
Following site selection, reference sites are surveyed (see Chapter 4) to col-
lect biological and physical data. The data are used to confirm and refine
the a priori classification, to characterize reference conditions, and to es-
tablish biocriteria (see Chapter 6). A general guide for confirming refer-
ence conditions, the effectiveness of classification is its ability to partition
variation. If a classification using a set of variables does not account for
variability, it is of little use; the greater the amount of variance accounted
for by classification, thejnore effective the classification.
A key analysis method for evaluating the strengm of metrics to detect
impairment is a graphic display using box-and-whisker plots (Fig. 3-3). In
Max
Min
/nuvnuvn
I
interquartile
ranga
tnnifntfn
T
scope for
dateeting
X
T
A general guide for
determining the
effectiveness of
classification is its
ability to partition
variation. . •
Reference Impaired
a. Metrics that have high values under reference (unimpaired) conditions.
Max
Min
I
T
T
scope) for
detecting
impairment
interquartile
range
T
Reference Impaired
b. Metrics that have low values under reference conditions.
Figure 3-3.—Generalized box-and-whlskor plots illustrating percentlles and the detec-
tion coefficient of metrics.
-------
BIOLOGICAL CRITERIA:
Technical Guidance for Streams and Small Rivers
The fundamental
problem of biological
assessment is not
whether two
populations (or
samples) have a
different mean, but
whether an individual
site (e.g., a lake) is a
member of the
least-impaired
reference population.
Since assessment is
based on multiple
metrics or species
composition,
multivariate tests may
be more convenient
than a succession of
individual tests.
the display shown here, the central point is the median value of the vari-
able; the box shows the 25th and 75th percentiles (interquartile range); and
the whiskers show the minimum to the maximum values (range). Box-
and-whisker plots are simple, straightforward, and powerful; the inter-
quartile ranges are used to evaluate real differences between two areas
and to determine whether a particular metric is a good candidate for use
in the assessment
Statistical methods used by biologists to determine whether two or
more populations have different means using t tests include the analysis of
variance and various nonparametxic methods. However, the fundamental
problem of biological assessment is not whether two populations (or sam-
ples) have a different mean, but whether an individual site (e.g., a lake) is
a member of the least-impaired reference population. If it is not, then the
second question is, how far has it deviated from that reference? Such bio-
logical assessment requires the entire distribution of a metric, which is eas-
ily shown with a box-and-whisker plot.
In operational bioassessment, metric values below the lower quartile
of reference conditions are typically judged impaired to some degree (e.g.,
Ohio Environ. Prot. Agency, 1990). The actual percentile chosen (25,10, or
5) is arbitrary and reflects the amount of uncertainly a monitoring pro-
gram can tolerate. The distance from the lower quartile can be termed a
"scope for detection" {Fig. 3-3). The larger this distance is, compared to the
interquartile range, the easier it is to detect deviations from the reference
condition. Thus, we. define a "detection coefficient'' as the ratio of the
interquartile range to the scope for detection. This coefficient is analogous
to the coefficient of variation (CV); the smaller the value, the easier it is to
detect impairment
Univariate tests of classifications include all the standard statistical
tests for comparing two or more groups: t test, analysis of variance, sign
test, Wilcoxon rank test, Mann-Whitney U-test (Ludwig and Reynolds,
1988). These methods are used to test for significant differences .between
groups (or classes) and to confirm or reject the classes. However, failure to
confirm the classification for any single response variable does not mean
that it will fail for other response variables.
Since assessment is based on multiple metrics or species composition,
multivariate tests may be more convenient than a succession of individual
tests. Discriminant analysis is a multivariate test included in many statis-
tical software packages. It is a one-way analysis of variance that tests dif-
ferences between a set of groups based on several response variables; and
it can be used as a test of classifications (Conquest et al. 1994), provided
that the assumptions of linearity and normality are met.
A satisfactory analysis is to develop quantitative, predictive models of
biological response to habitat variables. Using a defined population of refer-
ence sites that are relatively undisturbed, investigators can develop an em-
pirical (statistical) model that predicts biological communities based on the
habitat variables (e.g., Wright et aL 1984; Moss et aL 1987). Univariate mod-
els, such as multiple regression or analysis of covariance, are linear and re-
quire appropriately transformed linear variables. Community metrics tend
to respond linearly, or can be readily transformed to linearly responding
variables. Species abundances are typically nonlinear (usually unimodal) in
response to environmental variables and require nonlinear models.
-------
60
50
40
fi 30
20
10
i
Range
HELP IP EOLP WAP
ECOREGIONS
Rgura 3-4.—Indax of Blotlc Integrity at Ohio rafarwea afta*.
ECBP
10.0
•ff-
m
20.0
$
I
I 2 3
IJOG WA
Rgura 3-5.—Fish apadaa richnaaa aa • function of tha log of waterahad araa. Bara to
right indlcata ranga of obaarvatlona bafora ragraaalon and ranga of raalduala attar ra-
grasaion. Raalduala hava amallar variance than tha original obaarvationa.
To illustrate the role classification plays in partitioning variation, an
example is drawn from an extensive biosurvey database developed by the
Ohio EPA. A national map of ecoregions (Omernik, 1987) indicates that
parts of five ecoregions fall within Ohio. Comparison of the range of the
IBI, a measure of fish assemblage condition, illustrates that one ecoregion,
the Huron/Erie Lake Plain, is characterised by substantially lower values
than that observed in the other ecoregions (Fig. 3-4). The IBI was highest in
the Western Allegheny Plateau ecoregion.
Careful classification
contributes
significantly to the
refinement and use of
reference conditions
for establishing
biocriteria.
-------
BIOLOGICAL CRITERIA:
Technical Guidance for Streams and Small Rivers
In this example, classification is used iteratively, that is, decisions for
successive classifications are based on their ability to partition variation
from that which would be present on a statewide basis.
One way to partition variance is by examining possible gradients to
which the indicators of biotic condition may be related. Some possible gra-
dients are stream size, physical habitat condition, and stream gradient In
Figure 3-5, species richness is plotted against a log of watershed area; the
watershed area is used as a surrogate measure of stream size. The relation-
ship is clear: increasing species richness in the reference site occurs as
stream size (watershed area) increases. In this case, watershed size is used
as a covariate to provide adjustments in the expected number of species
associated with the drainage area within each class size.
In summary, careful classification contributes significantly to the re-
finement and use of reference conditions for establishing biocriteria. An it-
erative process is envisioned by which various classifications of regions
and subregions are proposed and evaluated against partitioning of vari-
ance: successful classifications partition variance effectively; ineffective
classifications provide little improvement beyond no classification. This
evaluation process should generally involve multiple metrics to judge the
success of multiple purpose ecoregion classifications.
Suggested Readings
Gallant; A.L. et aL 1989. RegionaUzation as a tool for managing environmental re-
sources. EPA 600/3-89/060. Environ. Res. Lab., U.S. Environ. Prot Agency,
Corvallis, OR.
Hughes, RM, DJP. Larsen, and JJvi. Omemik. 1986. Regional reference sites: A method
for assessing stream potentials. Environ. Manage. 10:629-35.
Iffrig, G.F. and M. Bowles. 1983. A compendium of ecological and natural subdivisions
of the U.S. Nat Areas J. 33-11.
Omenuk, JJvL 1987. Ecoregions of the conterminous United States. Annu. Ass. Am.
Geogr.77(l):118-2S.
Omemik, J.M. and G.E. Griffith. 1991. Ecological regions versus hydrologic units:
Frameworks for managing water quality. J. Soil Water Conserv. 46(5)33440.
US. Environmental Protection Agency. 1991d. Biological Criteria: Research and Regula-
tion Proceedings of the Symposium. EPA440/5-91-005. Off. Water, Washington,
DC.
-------
CHAPTER 4.
Conducting the
Biosurvey
^^^he primary goals of a bioasses-smenfc-bioaiteria program are to eval-
• uate water resource integrity, to provide information on the attain-
• ability and appropriateness_fif existing uses, and to determine the
extent and degree of water resource impairment
State bioassessment-biocriteria programs are usually designed to ad-
dress one or more of four water resource management objectives:
1. Aquatic Life Use Designation. Assess the aquatic life use attain-
ment for the state's streams and rivers. The incorporation of
bioassessment into this process is a major function of biological cri-
teria. '.'...
2. Sensitive Waters Identification. Characterize high quality waters
for protection. High quality waters may become part of the refer-
ence database or be classified separately as unique waters.
, 3. Diagnostics. Determine sources of impairment and potential
stressors. Biological response signatures are used in conjunction
with chemical, lexicological, and physical data to identify causes of
.impairment.
4. Program Evaluation. Monitor effectiveness of pollution abatement
programs, including wastewater treatment, watershed restoration,
and other water resource quality improvement programs Bio-
surveys and the biocriteria benchmarks are used to assess the re-
covery of the aquatic community.
Detailed multidiscipliriary ecological studies are often designed to
examine aquatic systems by measuring the'elements and processes of bib-
logical communities and by describing the physical and chemical charac-
teristics of the waterbody. Biological attributes that may be included in
such studies are individual health, trophic organization, measures of pri-
mary, secondary, and tertiary production (bodily growth and reproduc-
tion), recruitment of key species, predator-prey relationships, population
dynamics, and taxonomic structure of assemblages.
While seasonal accommodation is preferable for most bioassessment
programs, a single annual sample at a carefully selected time is sufficient
Purpose:
To provide guidance
to technical staff for
developing
cost-effective
biosurvey methods
with appropriate
resources, expertise,
and technical
considerations.
-------
Technical Guidance for Streams ana Smail nivers
Quality assurance
and control should be
a continuous process
throughout the
development and
operation of the
biocriteria program,
including all aspects
of the study.
Quality assurance
and control pervade
all aspects of an
ecological study:
m Study design
• Field operations
m Laboratory activities
• Data analysis
u Reporting
to characterize biological conditions accurately. Selection of the sampling
period should be based on efforts to minimize variability and maximize
the efficiency of the equipment and the accessibility of the biota being
sampled. Minimal between-year variability is partially addressed by sam-
pling at the same time each year to correct for the natural variability in
seasonal cycles.
Water quantity, quality, and climatic conditions should help rather
than hinder the efficiency of the sampling gear. For example, if certain
flow conditions are necessary for the equipment's performance, sampling
schedules should coincide with those conditions. Above all, sampling
should occur when the targeted assemblage or assemblages are accessible.
For fish, the optimal sampling period in most parts of the country is likely
to be from June through September; in general, these months avoid high
and low flows, spawning periods, and migration activity. Sampling should
be timed to avoid extremes in environmental and biological conditions.
The Quality Assurance Plan
A major consideration when designing bioassessment studies is not
whether a particular biosurvey approach is more refined than another, but
whether the selected approach will achieve the objectives defined in the
management plan. A dear definition of management responsibilities and
effective quality assurance and quality control procedures (see Chapter 2)
are essential to ensure the usefulness of monitoring data (Plafkin et al.
1989).
Quality assurance plans have two primary functions (Klemm et aL
1990). The first function is to ensure that the survey process reliably meets
program objectives; the second is to monitor the reliability of the survey
data to determine their accuracy, precision, completeness, comparability,
and representativeness.
A quality assurance plan should be developed at the onset of an eco-
logical study to delineate responsibility, establish accountability, and en-
sure the reliability of the data (Striblihg and Barbour, 1991). The quality
assurance plan should answer three questions:
• What kind of data or information is needed?
• Why is the information or data needed?
• What level of quality is needed to ensure the reliability of decisions
based on these data?
Quality assurance for a biocriteria program is concerned with the in-
tegrity of the data used to establish biocriteria limits and thresholds along
with the documentation that supports the derivation and maintenance of
the biocriteria. Quality assurance for specific studies pertains to the data
acquisition, their application to established biocriteria, and the validity of
associated judgments.
Quality assurance and control should be a continuous process
throughout the development and operation of the program, including all
aspects of the study: design, field collection, habitat assessment, laboratory
processing of samples, database management, analysis, and reporting. The
-------
Conducting the Biosurvey
appropriateness of the investigator's methods and procedures and the
quality of the data to be obtained must be assured before the results can be
accepted and used in decision making. Quality assurance is accomplished
through data quality objectives, investigator training, standardized data
gathering and processing procedures, verification of data reprodutibility,
and instrument calibration and maintenance.
The use of data quality objective's in field studies (Klemm et al. 1990;
Plafkin et al. 1989; U.S. Environ. Prot. Agency, 1984b, 1986) has much to
offer the biocriteria development and implementation process. Data qual-
ity objectives are qualitative and quantitative statements within the quality
assurance plan that address specific decisions or regulatory actions. Gen-
erally, data quality objectives consist of a priori statements about the level
of uncertainty a decision maker will accept in environmental data. In the
data quality objectives process, the quality of particular data is measured
by predetermined types and amounts of error associated with their collec-
tion and interpretation.
Quality Management
The implementation of a biocriteria program requires quality management
or the proper combination of resources and expertise. State agencies will
differ in levels of biological expertise, facilities, and quality of equipment
States already having well-developed bioassessment programs generally
have experienced and well-trained biologists, appropriately equipped fa-
cilities, and properly maintained sampling gear. A successful biocriteria
program depends on (1) a dear definition of goals, (2) the active use of
biomonitoring data in decision making, and (3) die allocation of adequate
resources to ensure a high-quality program. i
Biocriteria Program Structure, Personnel, and Resources
Monitoring agencies can and should enhance theii program by coopera-
tion with others. For example, they should seek coordination with, and
staff assistance from, state fishery, land management, geology, agriculture,
and water quality agencies. If federally employed aquatic biologists are
stationed in a state or if the state has substantial federal lands, cooperative
bioassessments and biocriteria development programs should be initiated.
Scientists at state universities should also be included in the planning and
monitoring phases of the program; their students make excellent field as-
sistants and future state ecologists.
• Personnel. Several trained and experienced biologists should be avail-
able to provide more thorough evaluations, support for various activities,
and serve as quality control checks. They should have training and experi-
ence commensurate with the needs of the program. At least one staff mem-
ber should be familiar with establishing a quality assurance framework.
The program should have at least one biologistjbr every" 4,000 miles of
stream in the state (CYoder and R. Thoma, personal communication).
• Resources. Laboratory and field facilities and semces should be in
place and operationally consistent with the designed jprposes of the pro-
gram so that high quality environmental data may degenerated and pro-
Monitoring agencies
can and should
enhance their
program by
coordination with, and
staff assistance from,
state fishery, land
management,
geology, agriculture,
and water quality
agencies.
-------
SIQLOGICAL CRITERIA.
Technical Guidance for Streams and Small Rivers
cessed in an efficient and cost-effective manner (Klemm et aL 1990). Ade-
quate taxonomic references and scientific literature should support data
processing and interpretation.
• Program Elements
1. Quality assurance and qualify control (e.g., standard operating
procedures, training)
2. Delineated reference conditions with annual updates
corresponding to seasons of sampling
3. Multiple assemblage biosurvey
4. Habitat assessment
5. Documentation of program and study plans
• Technical Considerations
1. Assign taxonomy to the lowest possible level based on published
keys and descriptions; maintain voucher collections
27Schedule multiple season sampling if warranted by type of impact
and life strategy of assemblage
3. Use multiple metrics to refine the assessment
4. Initiate detailed quality assurance and quality control procedures
in the field, laboratory, and taxonomy
5. Provide computer hardware and software (database management,
data analysis) with computer training of staff
Different levels of training and experience are necessary for the per-
sonnel involved in the design and implementation of biocriteria programs.
the qualifications and general job descriptions of four levels of profes-
sional staff are presented here. Also described are suitable substitutions for
these prerequisites and experience.
• Professional Staff
1. Level 4 — Plans, conducts, and supervises projects of major signifi-
cance, necessitating advanced knowledge and the ability to origi-
nate and apply new and unique methods and procedures. Supplies
technical advice and counsel to other professionals. Generally oper-
ates with wide latitude for unreviewed action.
Typical Title: Project Manager, Chief Biologist.
Normal Qualifications: Phi), or M.S. and equivalent experience. .
Experience: Ten or more years, at least three years in a leadership
or managerial position.
2. Level 31—Under general supervision of project manager, plans, con-
ducts and supervises bioassessment tasks such as trend monitoring
or special studies. Estimates and schedules work to meet completion
dates. Directs support assistance, reviews progress, and evaluates re-
sults; makes changes in methods, design, or equipment as necessary.
Operates with some latitude for unreviewed action or decision.
-------
• ' . . • . • . - ..
T>Tical Title: Project Biologist, Group Leader, Crew Leader
Normal Qualification: M.S., B.S., or equivalent experience.
^S^^^
Typical Title: Associate Biologist, Environmental Scientist
NonnalQttalifications:B.S. or equivalent experience" "
Experience: Three to eight yeaas in or rekfed to freshwater biology.
Typical Title: Field Technician,
Conducting the Biosuryey
Experience: zero to three years,
Experience/Qualifications Substitutions
-------
SiCLOGICAL CRITERIA.
Tednnical Guidance for Streams and Small Rivers
Effective quality
control procedures
are essential to insure
the usefulness of the
data for biocriteria
development and
environmental
decision making, and
to maintain the
bioassessment
program.
Protect M«iag*r/Pffncip*llriv*stigttor '
QA Officer
ECOLOGICAL PROJECT ACTIVITY CUSSES
SAMPLING
DESIGN
REU5
ACTIVITIES
LABORATORY
ACTIVITIES
DATA .
ANALYSIS
REPORTING
UNI
tor
.. CM*
QC
Coon*
Mtar
_j Reporting
IOC
KMalnttrpr
| S»npt4 Handing
Flgura 4-1^—Organizational chart Illustrating project organization and llnaa of raapon*
alblltty.
Quality management is an important planning aspect of the biocriteria
development process that focuses attention on establishing and improving
quality in all aspects of a project. Quality management requires that all
personnel involved in a biocriteria project (from senior management to
field and laboratory technicians) be aware of and responsive to data needs
and expectations. The surest way to achieve total quality management
(TQM) in an environmental program is to implement an achievable qual-
ity assurance program.
Quality Control Elements In an Ecological Study
Effective quality control procedures are essential to insure the usefulness
of the data for biocriteria development and environmental decision mak-
ing, and to maintain the bioassessment program. The organizational chart
in Figure 4-1 identifies the major activity classes in an ecological project
Table 4-1 outlines the quality control elements that are integral to those ac-
tivities.
All activity classes or phases of field ecological studies have potential
error sources associated with them (Barbour and Thornley, 1990). Some
general quality control elements for reducing the potential of error are dis-
cussed here; for more specific approaches, the investigator should refer to
Klemm et al. (1990) for benthic macroinvertebrates; and to Karr et al.
(1986), Lyons (1992), and Ohio Environ. Prot. Agency (1987) for fish.
• Study Design. Considerations relating to potential error in the sam-
pling design range from limited resources to insufficient sample replica-
tion to selection of inappropriate variables. Two important considerations
for developing a study design are interrelated: .the availability of baseline
data in historical information or pilot studies and the capacity to identify
-------
Conducting the Biosurvey
Table 4-1.—Quality control elements Integral to the activities In an •eoiogieal
study In sequence. '.-...••-,'
A. Quality Management '
1. Delineate responsibilities
. 2. Ust accountabHJtos
3. Identify qualty assurance officer
4. Develop quality assurance plan
5. Use bioassessment Information In decision making '
B. Study Oeeign • '
1. Pilot study or site reconnaissance '
2. Account for environmental strata
3. Incorporate historical data - '
a. Attempt to duplicate regimes , . ,
b. Attempt to use similar equipment (if appropriate to current objective)
4. Termination of control point
5. Areas of potential error .
a. Available resources . '
b. Logistics . . >. "
c. Response variables
d. Weather v
e. Seasonally
f. Site selection '. _
g. Habitat variability ,
h. Population variabilty
. i. Equipment .
6. Additional performance effect criteria '
C. Sample Collection
1. lrt»trum*rrt calibration and maintenance --
• 2. Field crew . . ' ' • '•..'.''.-'
a. Training
b. Evaluation ,
3. Field equipment . .
4. Sample handling
S. Effort checks
6. Field crew efficiency
7. Areas of potential error
a. Climate , , '
b. Site selection
c. Sampling efficiency of equipment
d. Equipment operation: human error . •
e. Reid notes
f. Samples •
i. Processing ,
ii. Transportation
yi. Tracking
8. Additional performance effect criteria ' , .
D. Sample Processing .
1. Sorting and verification
2. Taxonomy
3. Duplicate processing ' .
4. Archival procedures
5. Training .
6. Data handling
7. Interiaboratory training and collaboration
8. Areas of potential concern
a. Sample tracking
b. Improper storage
c. Sample preparation _ -
d. Reference error (taxonomy) ,
e. Taxonomic error (human)
(continued on next page)
-------
Technical Guidance for Streams and Small Rivers
Table 4-1.—Continued.
Two of the most
important
considerations in
developing a study
design are the
availability of baseline
data in historical
information or pilot
studies and the
identification of
potential sources of
error.
,
f. Counting error
g. Sorting efficiency
9. Additional performance effect criteria
E. DataAnarysis
1. Training
2. Data
a. Handling
b. Reporting
3. Standardized database
4. Standardized analyaes
5* Potf KttVICW
6. Range control .
7. Statistical power analysis
8. Areas of potential error
a. Inappropriate statistics
b. Errors in database
c. Database management
d. Programming errors
e. Analytical misinterpretation
9. Additional performance effect criteria
F. Report Preparation
.1. Training
2. Peer review .
• 3. Technical editor
4. Standard format
5. Areas of potential error
a. Transcription
b. Poor presentation
c. Obscure language
d. Addressing performance effect criteria
6. Additional performance effect criteria
potential sources of error. In fact, having adequate baseline information
may be the only way to identify sources of error. As more than one quality
control element may be used to reduce potential error, the interaction
among quality control elements must be considered to ensure the overall
quality of the plan.
Six qualitative and quantitative characteristics are usually employed to
describe data quality:
• Precision. The level of agreement among repeated measurements of
the same characteristic.
• Accuracy. The level of agreement between the true and the meas-
ured value; the divergence between the two is referred to as bias.
• Representativeness. The degree to which the collected data accu-
rately and precisely reflect the frequency distribution of a specific
variable in the population.
• Completeness. The amount of data coEected compared to the
planned amount.
• Comparability. The degree to which data from one source can be
compared to other sources.
-------
• CHAPTER 4:
Conducting the BiosUrvey
• Measurability. The degree to which measured data remain within
the detection limits of the analysis — often a function of the sensitiv-
ity of instrumentation.
These characteristics should be considered and denned before the data
collection begins. Taken collectively, they provide a summary characterization
of the data quality needed for a particular environmental decision.
• Field Operations. The major quality control elements in field operations
are instrument calibration and maintenance, crew training and evaluation,
field equipment sample handling, and additional effort checks. The poten-
tial errors in field operations range from personnel deficiencies to equip-
ment problems. Training is the most important quality control element for
field operations. Establishing and maintaining a voucher specimen collec-
tion is also important Vouchers are a mechanism for achieving the source
of the data, particularly for benthos. Use of a protocol for double data
entry and comparison can also increase the quality of a database.
• Laboratory Operations. The quality control elements in laboratory oper-
ations are classified as sorting and verification, taxonomy, duplicate proc-
essing, archival procedures, training, and data handling. Potential error
sources associated with sample processing are best controlled by staff train-
ing. Controlling taxonomic error requires well-trained staff with expertise
to verify identifications. Counting error and sorting efficiency are usually
the most prominent error considerations; they may be controlled by dupli-
cate processing, sorting, and verification procedures. Errors associated with
transcription during the data entry process can be significant In the labora-
tory, as in the field, the use of a protocol for double data entry and compar-
ison can increase the quality of a database, and the establishment and
maintenance of a voucher specimen collection should be considered.
• Data Analysis. Peer review and range of values are the important qual-
ity control elements for data analysis. Peer review helps control operator
variability, and measurement values must be kept within the range of nat-
ural or normal variability. Further, if inappropriate statistics are used to
analyze the data, erroneous conclusions may be drawn regarding trends.
Undetected errors in the database or programming can be disastrous, and
unless steps are taken to oversee data handling and analysis, problems re-
lated to database management will arise. The use of standardized com-
puter software for database management and analysis can minimize errors
associated with tabulation and statistics. A final consideration is the possi-
ble misinterpretation of the findings. These potential errors are best con-
trolled by qualified staff and adequate training.
• Reporting. The quality control elements in the reporting activity in-
clude training, peer review, and the use of a technical editor and standard
formats. The use of obscure language can often mislead the reader. Peer re-
view and review by a technical editor are essential to the development of a
scientific document. If the primary objective or central question of the
study is not specifically addressed in the report or the report is ambiva-
lent, then an error in the reporting process has occurred.
-------
3IOLOGSCAL CRITERIA. • ,
Technical Guidance for Streams and Small Rivers
Statement of Problem
- Site Description Characterization
of Problem
- Historical Data
- Data Gaps
I
| Specific Questions
Identify all Variables
Affecting Problem
Develop Judgment
Criteria
Select Variables
to be Measured
j Metric
Acceptable
Uncertainty
Sources of
Potential Error
Acceptability
of Study
Figure 4-2.-Summ«ry of Data Quality Objective (000) procew for ecological studies
(taken from Barbour and Thomley, 1990).
Data Quality Objectives
The data quality objectives process occurs during the final creation of the
research design. Although its aspects are inherently interrelated, the devel-
opment of data quality objectives is not directly linear. Rather, this develop-
ment is an iterative or circular process, as shown in Figure 4-2. The initial
statement of the problem evolves from specific questions about existing
data; then comes the identification and selection of the variables to be
measured, which influence the further refinement of the questions; and, fi-
nally, judgment criteria are developed for each variable, acceptable uncer-
tainty levels are established, and sources of potential error are identified.
The result of the data quality objectives process is a formal document
that can be separate from or part of a formal quality assurance plan. It may
also be included in narrative form in a project workplan. The data quality
objectives document should state the study's primary objectives, specific
questions, and rationale; it should also justify the selection of variables, es-
tablish judgment criteria (by developing a logic statement for each van-
-------
able), and specify acceptable levels of uncertainty. This information does
not have to be presented in a stepwise fashion, but it should be readily
available. , '
All staff involved in the biocriteria development process — senior
management, program staff, and all technical staff — should be included
in formulating data quality objectives. In fact, quality management in eco-
logical studies reqiures that all personnel involved in a project be aware of
and responsive to detailed needs-and expectations. If appropriately exe-
cuted, data quality objectives will formalize and document all manaee-
^™H deds^n/o^' *• necessary data collection and analysis
procedures, the data interpretation steps, and the potential consequences
of making an incorrect decision. n
Further details of quality assurance and control programs specific to
fish and macroinvertebrate field surveys, and methods for determining bi-
?Q£^COnditi0n' m Provided in Klemm et aL (1990) and PJafkin et aL
(1*89). General guidance for developing comprehensive quality assurance
CTR S?2niaa"?£7 **«:**** m ihe C°de of Federal Regulations (40
<-f R Part 30), and U.S. Environ. Prot Agency (1980a,b; 1984a,c). For infor-
SSS?^ Stance specific to data quality objectives, see Klemm et aL
(1990), Plafkin et al. (1989), and UOn^iron. Prot. Agency (198^986)
Study Design
The primary focus of the study design is to establish objectives, and the
statement of the problem to be resolved is the central theme of the objec-
tives. For instance, the central problem or question may be, "Is the biotoei-
cal integrity of a specified area of a particular watershed impaired by the
operation of a wastewater facility?' This question has sev^ralfeSures
that, in turn, provide a foundation for more-specific questions. The first
feature is the concept of biological integrity, which implies that a measS-
able reference condition exists for the aquatic assemblages being studied.
vV^Tu?!11?6 delineates the spatial area to be evaluated in the water-
shed; the third diagnoses whether or not a problem is attributable to the
operation of the facility. Still more specific questions, or testable hypothe-
ses, related to the central problem may be constructed.
l.Is impairment of the biological condition detectable in the algae,
fish, or macroinvertebrate assemblages?
2. Is degradation altering the energy base, water quality, flow regime,
habitat structure, or other aspect of the environment?
3. Is there a history of problems in mis area of the watershed?
4. What was the historical condition of the aquatic community?
Based on these questions, it is possible to select the biotic and abiotic
variables to be measured. For each variable, an acceptable level of degra-
dation should be identified before conducting the biosurvey. Thus, the
study design includes selecting the aquatic assemblages/resolving the
technical issues associated with their ecology and proper sampling, estab-
lishing standard operating procedures, and beginning the biosurvey pro-
gram.
Conducting the Biosurvey
The primary focus of
the study design is to
establish objectives.
A critical decision in
the design of
biocriteria programs
is how to select
appropriate indicators
of biotic condition.
-------
BIOLOGICAL CRITERIA: •
Technical Guidance for Streams and Small Rivers
The importance of
the periphyton
assemblage within ;
most stream
ecosystems makes it
a prime candidate for
consideration as a
bioassessment- •
biosurvey target
Biosurveys of Targeted Assemblages
A critical decision in the design of biocriteria programs is how to select ap-
propriate indicators of biotic condition. Biosurvey of the targeted assem-
blages is the most widely employed approach to biocriteria development
This approach, which has been used by Ohio, Illinois, North Carolina,
Maine, Arkansas, New York, and Vermont, focuses on a selected compo-
nent of the biological community; it samples one or several specific
aquatic community segments to measure biological condition. Monitoring
the specific characteristics of these assemblages helps assess the effects of a
variety of environmental conditions (Ohio Environ. Prot Agency, 1987).
A number of different organisms associated with lotic systems (i.e.,
streams and rivers) lend themselves to bioassessment procedures. Com-
monly measured assemblages include, but are not restricted to,
macrophytes, algae, macroinvertebrates, and fish. The targeted assem-
blage approach to bioassessment can also focus on a single assemblage
(e.g., periphyton) or several assemblages (e.g., periphyton, macro-
invertebrates, and fish). The attributes measured may be functional pa-
rameters, such as photosynthesis or respiration, or other attributes, such as
individual health. Examples of widely used methods and techniques for
targeted assemblages are found in Karr (1981), Karr et al. (1986), Ohio En-
viron. Prot. Agency (1987), Plafkin et al. (1989), Standard Methods (1989),
U.S. Environ. Prot. Agency (1990), and Weber (1973). The primary advan-
tages of this approach are its flexibility, practicality, cost-effectiveness, and
relative scientific rigor.
Attributes of Selected Assemblages
• Periphyton. The periphyton assemblage is composed of benthic algae,
bacteria, their secretions, associated detritus, and various species of
microinvertebrates (Lamberti and Moore, 1984). Periphyton are an impor-
tant energy base in many lotic situations (Dudley et aL 1986; Minshall, 1978;
Steinman and Parker, 1990) and serve as the primary nutrient source for
many stream organisms (Lamberti and Moore, 1984). The capacity of ben-
thic assemblages .to colonize and increase in biomass is influenced by vari-
ability in stream channel geomorphology, flow rates, herbivore grazing
pressure, light intensity, seasonality, and random processes (Coleman and
Dahm, 1990; Grimm and Fisher, 1989; Hamilton and Duthie, 1984; Korte
and Blinn, 1983; Lamberti et al. 1987; Patrick, 1949; Poff et al. 1990; Stein-
man and Mclntire, 1986,1987; Steinman et aL 1987; and Stevenson, 1990).
The importance of the periphyton assemblage within most stream eco-
systems makes it a prime candidate for consideration as a bioassessment-
biosurvey target. More specific advantages are outlined by Plafkin et al.
(1989):
• The rapid algal reproduction rates and short life cycles of periphyton
make them valuable indicators of short-term impacts.
• Physical and chemical factors have direct effects on the structure and
functions of periphyton and on their production.
• Periphyton sampling methods are straightforward, and the samples are
easily quantified and standardized.
-------
Conducting the Biosuwey
• Methods have Also been standardized for recording functional and
nontaxonomic characteristics of periphyton communities, such as
biomass and chlorophyll measurements.
• Algal components of periphyton are sensitive to some pollutants to
which other organisms may be relatively tolerant
• Macrophytes. The macrophyte assemblage consists of large aquatic
plants that may be rooted, unrooted, vascular, or elgiforms. Both emergent
and submergent macrophytes provide numerous benefits to streams and
small rivers thus helping them to stapport healthy, dynamic, biological
communities (Campbell and Clark, 1983; Huriey, 1990; and Miller et aL
1989). Some understanding of the distributional characteristics and envi-
ronmental conditions affecting macrophytes (Hynes, 1970) enhance men-
use in bioassessment strategies. Hynes (1970) and Wesflake (1975) discuss
differences in lotic macrophyte assemblages based on habitat factors such
as water hardness, pH, gradient, and propensity for siltation.
Some investigators have emphasized the influence of macrophytes on
habitat structure (Carpenter and Lodge, 1986; Gregg and Rose, 1982,1985;
McDermid and Naiman, 1983; Miller et al. 1989; Pandit, 1984); others have
studied water chemistry, nutrient cycling, and macroinvertebrate coloniza-
tion (McDermid and Naiman, 1983; Miller «t al. 1989). Pandit (1984),
Seddon (1972), and Westlake (1975) pointed to the use of macrophytes as
an indicator assemblage in lotic situations.
Aquatic macrophytes are an important food source for birds and mam-
mals. Fassett (1957) lists 36 species of waterfowl, nine marshbirds, four
shorebirds, and nine upland game birds that feed on these plants. He also
lists beaver, deer, moose, muskrat, and porcupines as aquatic macrophyte
herbivores. The use of macrophytes in bioassessment programs has nu-
merous advantages:
» Macrophyte taxonomy to the generic level is relatively straightforward.
• Because the establishment of macrophyte populations in a specific
habitat depends partly on local environmental conditions, they are
potentially very useful as site-specific indicators.
• Because their specific microhabitat structure does not limit germination,
macrophytes are potentially found in high population densities.
• The growth patterns of individual macrophytes are directly influenced
by herbivore activity.
• The longevity, distribution, and rate of their population growth may
directly reflect prevailing conditions.
• Macroinvertebrates. Macroinvertebrates are the visibly
-------
Technical Guidance for Streams and Small Rivers
Fish assemblages
are well suited to help
define environmental
conditions because
fish inhabit the
receiving waters
continuously, and with
lifespans up to 10
years, they can easily
represent the
integrated historical
effects of chemical,
physical, and
biological habitat
factors.
ever, the overall assemblage responds more slowly. Other advantages of
using macroinvertebrates include the following:
• Sampling methods are well developed and require minimal personnel
and inexpensive gear.
• Macroinvertebrates play a major role in the nutritional ecology of
commercial and sport fisheries.
• Most streams support sufficient abundance levels for assessment.
• Molluscs, many species of Crustacea, and some Insects are largely
immobile. As residential organisms, they are particularly valuable
indicators of site conditions over time.
• Many states have already performed background benthic surveys, have
personnel trained in benthic biology, and can often get assistance in
sampling from lay groups.
• Fish. Fish assemblages are well suited to help define environmental
conditions — either natural or impaired. Fish are long-lived and inhabit
the receiving waters continuously. With lifespans up to 10 years, they can
easily represent the integrated historical effects of chemical, physical, and
biological habitat factors (Ohio Environ. Prot. Agency, 1987). Power (1990)
found that fish exert significant influence on the food chain in lotic sys-
tems. More specific advantages of using the fish assemblage for bioassess-
ment (Karr et aL 1986; Flafkin et aL 1989) include the following:
• Fish are usually present in lotic systems except for some headwaters.
• Their populations generally include species that feed at a variety of
trophic levels.
• Species composition and dominants are relatively stable in most areas.
• The migration patterns and wide-ranging foraging behavior of some
fish allow investigators to accumulate effects from relatively large-scale
habitats.
. • In comparison to other potential bioassessmenl: groups, fish are
relatively easy to identify.
• Autecologjcal studies for many freshwater species are extensive, so their
life histories are relatively well known.
• Public, and therefore, legislative appreciation for fish is apparent in the
fishable goal of the dean Water Act, the Endangered Species Act (50
percent of "endangered" vertebrate species are fish), and in more
specific commercial and sport fisheries legislation.
• Historical survey data are probably best documented for fish.
• Investigators can often get assistance from lay groups.
• Wildlife. Mammals, birds, reptiles, and amphibians can also provide
valuable information for bioassessment decisions. Croonquist and Brooks
(1991), applying the concept of response guilds, found that bird species
with high habitat specificity decrease with increasing habitat alteration.
-------
Conducting the Biosurvey
This approach has considerable potential for development of an avian
index of biotic integrity. Birds have been shown to reflect the condition of
riparian systems.
Because amphibians live part of their life cycle in an aqueous or damp
environment, they are a link between the aquatic and terrestrial environ-
ments. They are also sensitive to lifctoral zone and riparian disturbances
and to changes in their food resources (macroinvertebrates and peri-
phyton). The latter may affect their fitness or force them to emigrate from
the home range to another foraging zone. Other advantages of including a
biosurvey of mammals, birds, and amphibians in biomdnitoring programs
are the following: aFiF«»
* Their longer life spans make them well suited for evaluation of
cumulative effects.
• The relatively large body size of birds and their behaviors (e.g., singing)
allow visual and auditory observation to supply most of the necessary
information. -
• Birds are sensitive to riparian alteration.
• Wildlife taxonomy is well understood.
• Many biomarkers — physical and chemical alterations in the species in
response to contamination—appear in these organisms, and an
increased likelihood for sublethal effects in non-emigrating individuate.
• Trapping techniques for small mammals axe relatively straightforward,
and their tracks and droppings also provide easily attainable survey
data. '-'•••
* The public is usually able to assist in conducting wildlife assessments.
Synthesis
Many bioassessment programs focus on a single assemblage for reasons of
regulatory focus or mandate, available expertise, resource limitations, or
public awareness and interest. However, state agencies are encouraged to
incorporate more than one assemblage (e.g., fish and benthic
macroinvertebrates) into their assessment programs. Biological programs
that use two or three assemblages and include different trophic levels
within each group (e.g., primary, secondary, and tertiary consumers) will
provide a more rigorous and ecologically meaningful evaluation of a
system's biological integrity (US. Environ. Prot. Agency, 1990) and a
greater range of temporal responsiveness.
Impairments that are difficult to detect because of the temporal or spa-
tial habits Or the pollution tolerances of one group may be revealed
through impairments in different species or assemblages (Ohio Environ.
Prot. Agency, 1987). Mount et al. (1984) found that benthic and fish assem-
blages responded differently to the same inputs in the Ottawa River in
Ohio. Benthic diversity and abundance responded negatively to organic
loading from a sewage treatment plant and exhibited no observable re-
sponse to chemical input from industrial effluent. Fish exhibited no re-
sponse to the organic inputs and a negative response to metals. In a more
Biological programs
that use two or three '
assemblages and
include different
trophic levels within
each group will
provide a more
rigorous and
ecologically
meaningful evaluation
of a system's
biological integrity
and a greater range
of temporal
responsiveness.
-------
-
Technical Guidance for Streams and Small Rivers
Aquatic organisms
respond to stress in a
variety of ways
ranging from
alterations in
community
composition and
structure to increases
or decreases in the
biomass of a single or
multiple species, or
mortality.
recent assessment, the Ohio EPA found that distinct response signatures
(Yoder, 1991) in both fish and macroinvertebrate assemblages indicated an
adverse effect from the sewage treatment plant Selection of aquatic com-
munity components that show different sensitivities and responses to the
same disturbance will help identify the nature of a problem (U.S. Environ.
Prot. Agency, 1990).
The selection of a single assemblage for impact assessment risks pro-
viding inadequate resolution for certain impacts that are highly seasonal
in occurrence. Organisms having short life cycles may not reflect direct ex-
posure to highly variable impacts at critical times or when complex cumu-
lative impacts are present Depending on the collection period, those
organisms may provide a false sense of ecosystem health though other as-
semblages of longer-lived populations are under stress. In cases in which
periodic pulses of contaminants may occur, long-lived populations may be
slow to exhibit response, whereas short-lived organisms may be severely
affected.
The occurrence of multiple stressors and seasonal variation in the in-
tensity of stressors require that more than one assemblage be incorporated
into biocriteria programs whenever practical Not all assemblages dis-
cussed here are in constant contact with the aquatic habitat component
Those that are — the macroinvertebrates, macrophytes, fish, and peri-
phyton — will exhibit direct, and potentially more rapid, responses to
water resource degradation. The assemblage comprising mammals, birds,
and amphibians indicates the quality of the riparian corridor and may re-
flect local land use impacts on the water resource.
Aquatic organisms respond to stress in a variety of ways ranging from
alterations in community composition and structure to increases or de-
creases in the biomass of a single or multiple species, or mortality. Fish
and drifting macroinvertebrates also exhibit avoidance behavior by seek-
ing refugia from short-and long-term disturbances.
Careful selection of target taxonomic groups can provide a balanced
assessment that is sufficiently broad to describe the composition and con-
dition of an aquatic ecosystem, yet practical enough for use on a routine
basis (Karr et al. 1986; Lenat, 1988; Flafkin et al. 1989). When selecting
community components to include in a>iological assessment, primary
emphasis should be given to including species or taxa that (1) serve as ef-
fective indicators of high biological integrity, that is, those likely to live in
unimpaired waters, (2) represent a range of pollution tolerances, (3) pro-
vide predictable, repeatable results from consistent sampling, (4) can be
readily identified by trained state personnel (U.S. Environ. Prot. Agency,
1990), (5) show a consistent response to pollution stress, and (6) closely
represent local, indigenous biota.
Technical Issues
The methods and procedures used in bioassessment programs should be
based on the study objectives and associated technical issues, including
site selection and sampling regime, the selection of the proper sampling
period, and determination of the appropriate habitats to be sampled.
-------
CHAPTER 4:
Conducting the Biosurvey
Selection of the Proper Sampling Periods
The ideal sampling procedure is to survey the biological community with
each change of season, then select the appropriate sampling periods that
accommodate seasonal variation. Such indexing makes the best use of the
biological data. It ensures that the sources of ecological disturbance will be
monitored and trends documented, and that additional information will
be available in the event-of spills or other unanticipated events.
In this way, the response of the community to episodic events (e.g.,
chemical spills) can be assessed throughout the year. Seasonal impacts,
which may be highly variable, cam be more effectively characterized
through more frequent sampling. Impacts from certain stresses may occur
or be 'worst-case* at specific times of the year, and it may be important to
provide adequate documentation of the biological condition during these
times. EPA's Science Advisory Board (SAB) suggests that sampling should
— at a minimum — include the major components of the fall-winter and
spring-summer (or wet season-dry season) community structure. The Flor-
ida Department of Environmental Protection has instituted a program that
encompasses sampling during two index periods that correspond to this
approach. . , -—- • .
If some fish and invertebrate life cycles (e.g., spawning, growth, mi-
gration, and emergence) cause marked seasonal changes in stream assem-
blages, then each sampling season will require a separate reference
database, metrics,, and biocriteria. When such multiple index periods are
used, the operational costs, at least initially, may be considerably higher
than if surveys were conducted only once a year. Therefore states must
weigh their needs and the long-term value of this information against
these costs. Seasonally must always be considered, and where possible,
year-round data should be developed even if it has to be phased in slowly
over time and as budgets allow. ,
• The alternative, a single index period, will be deficient it will hot doc-
ument spills or other single episode or transitory events including stresses
that take place in other seasons, it should be selected only if seasonality is
not a factor in the program Objectives. Still, the major or initial applications
of state biocriteria are likely to be assessment and management planning
related to chronic habitat alteration and point and nonpoint sources. Such
chronic stress impacts are more efficiently assessed with a single index pe-
riod approach. Resident fish and benthic invertebrate assemblages inte-
grate stress effects over the course of a year and their seasonal cycles of
abundance and taxa composition are fairly predictable, within the limits of
interannual variability. Single season indexing also represents a cost sav-
ings compared to seasonal or more frequent sampling.
Given these considerations, state managers must choose the approach
most appropriate to their needs and budgets. They must avoid the tempta-
tion to spread multiseason sampling so thin that neither seasonal measure-
ments nor indexing are properly achieved. It is better to do a single index
period well than to do two poorly. Presuming, therefore, that most states
will initially design their biological criteria programs around single season
surveys, the following discussion emphasizes index period designs.
The optimal biological sampling period will be consistent .with recruit-
ment cycles of the organisms from reproduction to emergence and migra-
The ideal sampling
procedure is to
survey the biological
community with each
change of season,
then select the
appropriate sampling
periods that
accommodate
seasonal variation.
State managers must
choose the approach
most appropriate to
their needs and
budgets.
-------
BIOLOGICAL CRITERIA:
Technical Guidance for Streams and Small Rivers
The optimal
biological sampling
period will be
consistent with
recruitment cycles of
the organisms from
reproduction to
emergence and
migration, such that
the maximum amount
of information can be
derived from the data.
tion, such that the maximum amount of information can be derived from
the data. Optimal conditions for biological sampling can be defined as that
period of time during which the target assemblages have stabilized after
larval recruitment and subsequent mortality and the use of their niche
space is at its fullest. Where necessary, a compromise between biologically
optimal conditions and water and flow conditions appropriate for the
sampling gear must be made. Therefore,, selection of the sampling period
should be based on efforts to
• minimize between-year variability resulting from natural events/
• maximize gear efficiency, and
• maximize target assemblage accessibility.
Minimal between-year variability is partially addressed by sampling
within the same season as the previous year's sampling. Applying this
temporal consideration to sampling corrects for the natural variability re-
sulting from seasonal cycles. Water quantity and quality and climatic con-
ditions should be such that sampling gear is at its maximum efficiency. If
certain flow conditions are necessary for gear performance, sampling
shouid-be targeted to coincide with those conditions. Finally, sampling
should occur when there is maximum, accessibility to the targeted assem-
blage or assemblages. For fish, the optimal sampling period is likely to
avoid extremes in environmental and biological conditions.
Field collections scheduled to correspond to the optimal biological
sampling period provide the most accurate assessment of community re-
sponse to adverse conditions over an annual cycle. Sampling during these
periods may not be logistically feasible, however, as a result of adverse
weather conditions, staff availability, scheduling constraints, or other fac-
tors. The nature of the suspected stressor is an especially important con-
sideration. An agency may be required to perform biological sampling
during periods of greatest environmental stress, such as low flow and high
temperature periods for point source discharges or high flow and runoff
periods for nonpoint source discharges.
Although an estimate of aquatic community structure during optimal
biological conditions should reflect the effect of, or recovery from, environ-
mental stress periods (Ohio Environ. Prot Agency, 1987), assessment of
worst-case conditions may be needed under certain permitting regulations
or as a follow-up to sampling during biologically optimal periods in which
impairment was detected.
Ecological conditions and, thus, optimal sampling periods, vary sea-
sonally as a result of regional climate patterns and the life cycles of the
biota. Seven major climatologjcal regions are represented within the con-
tiguous United States (Fig. 4-3). The primary influence of seasonal changes
in temperature and rainfall on stream biota is on biological processes (e.g.,
production, growth, reproduction, distribution, and locomotion). The level
of biodiversity may also change seasonally. Even within an ecological re-
gion, some scaling of the optimal collection period may be necessary, de-
pending on the elevation of the site, the habitat type, and other broad
environmental variables.
Temperature and rainfall are the principal weather factors influencing
the selection of sampling protocols and timing. Most sampling will be im-
-------
CHAPTER 4:'
Conducting the Biosuivey
Rgure 4-3.—Classification of U.S. dlmatcloglcal regions.
possible in frozen streams or during extreme high flows. Even subtle
changes in temperature and flow may preclude certain kinds of sampling
by affecting the equipment or the distribution of target assemblages.
The purpose of the biological sampling program (trend monitoring,
special studies) also influences seasonal considerations. Special studies
may be conducted at any time depending on need; but trend monitoring
studies will focus on annual sampling events with varying sampling fre-
quencies. The most appropriate season for such collections is determined
by considering all technical and nontechnical factors. Technical factors in-
clude the selected assemblage, recruitment cycles, and severity of degrada-
tion or contamination; nontechnical, factors include such matters as
logistics and personnel. From a practical standpoint, many states may se-
lect a sampling period that includes the summer and early fall months.
the investigator must carefully define the objectives of a monitoring
program before the design issues can be resolved. Will specific questions
. be answered by sampling during periods of optimal biological condition
or during periods of maximum impact? (These two periods may coincide.)
Seasonal considerations are important because community taxonomic
structure and the functional composition of some assemblages undergo
natural changes in each season and annual cycle.
Natural cycles may also be influenced by chemical or physical alter-
ations. From the traditional perspective of evaluating pollution impacts,
summertime low flow conditions are often chosen to assess effects from
point source discharges. Low flow conditions capture the effects of minimal
effluent dilution in combination with the natural stressors of low water ve-
locity and high temperature. Minima], effluent dilution occurs in summer
because the lower quantity of water decreases the ability of the receiving
waters to reduce the concentration levels of discharged compounds.
The effects of nonpdint source pollution on the aquatic community are
evaluated during the recovery period following high,flow because these
effects are largely driven by runoff in thfe watershed. Nonpoint source
loadings are estimated using samples collected during periods of high
/
Special studies may
be conducted at any
time depending on
need; but trend
monitoring studies will
focus on annual
sampling events with
varying sampling
frequencies.
-------
Technical Guidance for Streams and Small Rivers
The major factors •
that affect the
selection of an
appropriate sampling
season include the
seasonal attributes of
the aquatic
community and the
administrative issues
of sampling efficiency,
safety, regulatory
requirements, and
appropriate metrics .
for data analysis.
flow. Their actual effects, however, should be based on sampling outside
the flow extremes. The effect of regulated and minimum flows are a partic- ;
ular problem during the winter season in the western United States. Regu-
lated flows are a function of anthropogenic activity, usually associated
with dams and reservoirs. Sampling activities should be avoided during
high and low extremes. .
Special studies conducted by state agencies in response to specific reg-
ulatory, requirements or catastrophic events (e^g./ oil spills) may not occur
in an optimal season. In these situations, the data should be interpreted
through concurrent reference data or through a seasonal adjustment to es-
tablished reference data. If base biocriteria are established for a reference
database for a single season, then data collected from the test sites during
this season are directly comparable. ;
Two options are available for collections at test sites during seasons
other than that used for base criteria. First, selected reference stations can
be sampled concurrently with the test sites to provide baseline compari-
sons for data interpretation. Criteria established during the optimal season
represent a range of values that can be extrapolated to other seasons. In
this manner, a percentage of the reference may be acceptable as an alter-
nate criterion.
The second option may be to develop adjustments for an annual cycle.
This can be done through seasonal collections of the reference database to
document natural seasonal variation. Alternatively, a knowledge of sea-
sonal appearance and disappearance of particular forms can be used to de-
velop adjustments. - , •
The major factors mat affect the selection of an appropriate sampling sea-
son must be considered in light of the sampling objectives of the survey. This
discussion has focused on the seasonal attributes of the aquatic community.
The administrative issues of sampling efficiency, safety, regulatory require-
ments, and appropriate metrics for data analysis are equally significant
Benthos
Maximum information for a benthic community is obtained when most of
its populations are within a size range (later instars) that can be retained
during standard sieving and sorting and be identified with the most confi-
dence. Reproductive periods and different life stages of aquatic insects are
related to the abundance of particular food supplies (Cummins and Mug,
1979). Peak emergence and reproduction typically occur in the spring and
fall, although onset and duration vary somewhat across the United States.
During peak recruitment of the young, approximately 80 percent are too
small to be captured in sufficient numbers to characterize the community
accurately, and the food source requirements for early instars may be dif-
ferent from those for later instars. Therefore, the biologically optimal sam-
pling season occurs following the period of initial recruitment and high
mortality of young, and when the food resource has stabilized to support a
balanced indigenous community.
The. comparative time frames for sampling the benthic community are
illustrated in Figure 4-4. The seasonal timetable shows annual high and
low flow periods, emergence peaks for aquatic insect communities, and bi-
ologically optimal sampling periods (BOSP) for a stream in the New Eng-
land region. High and low flow correspond to periods of high and low
-------
Conducting the S/oso/vey
Low Flow / Low Temp. (Ice)
High
Flow
Low Flow
High
Temp.
FJgura 4-4.—Biological and hydroteglcal (factor* for sampling parted aatoctton In tha
Northaast (maeroinyartabrataa). Tha gray araa la tha oyariap batwean amorganea and
raeuHmant •
rainfall and associated runoff. Emergence is triggered by average daily
temperature and photoperiod and usually occurs at peak intervals in
spring and fall. The biologically optimal sampling period falls between the
peaks in late winter and late summer and occurs after the population has
been exposed to two-thirds of the aquatic phase of the organism's life
cycle measured in degree days (that is, in units calculated as the product
of time and temperature over a specified interval).
In this example (Fig.4-4), sampling in July and early August satisfies
most of the criteria for collecting a representative sample at a time of sig-
nificant chemical contaminant stress. It should be noted that chronic non-
point source impacts such as sedimentation will be reflected in the quality
of the benthic community after flow has returned to near normal following
high flow conditions. . .'.''..
In the context of a single population, seasonality may be a significant
factor. The early instars are small and difficult to identify, and the young
nymphs have a generalized feeding strategy of collecting and scavenging.
Only in later instars does feeding specialization occur and the quality of
the food source become reflected in the condition of the population. In the
case of Stenonema, the middle and late instars specialize as scrapers. Scrap-
ers are Often considered a pollution sensitive functional feeding group be-
cause their food source — diatom algae — responds to the early effects of
pollution within the stream.
Periphyton
Periphyton assemblages are associations of algae, bacteria, and fungi that
colonize the substrates in a stream. For purposes of bioassessment, most
periphyton evaluations focus on diatom algae. The periphyton assemblage
exhibits different seasonal abundance patterns than fish or benthos. The
key difference is that periphyton assemblages are sufficiently abundant to
be collected year-round from streams in temperate zones. Their biologi-
-------
Technical Guidance for Streams and SmaU Rivers
cally optimal sampling period may be based on relatively stable condi-
tions but must also account for the comparison of diatom assemblages
within similar stages of seasonal succession.
The limiting factors for diatoms are light, temperature, nutrients,
water velocity, grazing, and interactions among algae via metabolites. Ob-
viously, the abiotic factors go through an annual cycle of change and, like
benthos, the assemblage composition shifts as the changing conditions
favor hew species. This process of seasonal succession creates significant
seasonal differences in periphyton assemblages that must be considered in
developing a study design. Besides changes in periphyton species compo-
sition, additional seasonal issues must be controlled to compare collections
among sites and annual trends. Two major considerations are (1) the dif-
ferences in biomass related to light and temperature regimes and (2) the
comparisons of periphyton assemblages that have been subjected to heavy
rains and scour with those that have matured under more stable hydro-
logical conditions. Differences in light and temperature regimes may re-
flect human influences, for example, alterations of the stream channel and
removal of riparian vegetation.
Fish —
Like periphyton and benthic invertebrates, the fish fauna at a site is likely
to vary seasonally. In the Northwest, for example, annual spawning migra-
tions of anadromous salmonids set in motion a seasonal cycle of major im-
portance to the biota. Seasonal migrations of fish are less striking but
common in other areas as well Most frequently, fish movements involve
upstream movements in search of spawning areas to serve as nesting and
nursery areas for young fish. Upstream areas often provide richer food
supplies and lower predation rates than downstream areas.
Because of geographic variation in flows and temperatures, no general
pattern occurs across all regions. A seasonal timetable representative of
physical conditions and fish assemblage activities in the New England re-
gion is illustrated in Figure 4-5, Unless the sampling objective includes the
Low Flow / Low Temp. (Ice)
High
Flow
Low Flow
High
Temp.
High
Flow
Coldwater
Fish Spawning
Anadromous
Migration
Wannwater
Rgure 4-5.—Biological and hydrologlcal factors for aampllng period selection In the
Northeast (fish).
-------
Conducting the Biosurvey
study of unusual flow conditions and concurrent bibtic responses, field
sampling protocols should avoid extreme flow conditions (low or high)
that may represent unusual stress, assemblage instability, or result in dan-
ger to field crews.
Sampling in several regions of the country has demonstrated that opti-
mal fish sampling periods can be defined with relative ease. Generally,
sampling periods should follow the spring spawning migrations that coin-
cide with periods of high flow. Most states in eastern North America select
the summer period for sampling (June through August) to coincide with
periods of low to moderate stream flow and avoid the variable flow condi-
tions of early spring and autumn (Karr et al. 1986). Fish assemblages dur-
ing summer are relatively stable and contain the fuU range of resident
species, including all major components of age-structured populations.
Angermeier and Karr (1986) have outlined sampling rationale, including
the merit of excluding ypung-of-the-year (YOY) from spring and late sum-
mer samples to reduce variability and the problems of identifying and
sampling very small fry. They demonstrate that excluding YOY from most
analyses improves reliability and does not weaken the interpretation of the
system's condition. ,
The scenario presented in Figure~4-5 identifies high and low flow peri-
ods in early spring and late summer for streams in the northeastern
United States. The number of species is likely to peak in the spring with
the spawning migration; the number of individuals will peak in the early
autumn with the addition of YOY. The biologically optimal sampling pe-
riod (BOSP) corresponds to seasonal effects within the fish assemblage
and the flow dynamics that influence sampling efficiency. Because the
physical condition of the streams affects the efficiency of fish sampling
gear, it also affects the nature or quality of the resulting data. For example,
the effectiveness of passive equipment (e.g., trap nets) can be substantially
reduced during periods of high or low flow, and the efficiency of active
equipment (e.g,, electrofishing gear) is reduced by turbidity, water temper-
ature, and conductivity.
Sampling can typically begin in May or June in most areas and pro-
ceed into September unless unusually low flow periods occur during late
summer drought. The probability that low, flow periods will occur in late
summer increases in watersheds that have been severely modified by ur-
banization or agricultural land use, in which case low flow sampling
should be avoided.
Selection of Habitat for Aquatic Assemblage Evaluations
Stream environments contain a number of macro- and microhabitat types,
including pools, riffles, and raceways, or surface and hyporheic zones. The
latter refers to regions of saturated sediment beneath or beside the stream
(Lincoln et al. 1982). Larger rivers have even more complex habitat config-
urations. Because no single sampling protocol can provide accurate sam-
ples of the resident biota in all habitats, decisions about habitats are critical
to the success of a biocriteria program. These decisions are usually made
in concert with the decision about the assemblages to be sampled, the sam-
pling methods to be used, and the seasonal pattern of sampling.
> Selection of habitats for sampling may be influenced by institutional
requirements, such as sampling and analysis protocols that are part of an
Decisions about
which habitats to
sample are critical to
the success of a
btocriteria program.
-------
Technical Guidance for Streams and Small Rivers
A major
consideration in the
development of
bioassessment
procedures is whether
sampling all available
habitats is necessary
to evaluate biological
integrity at a site or
whether sampling
only selected habitats
can provide sufficient
information.
i
existing monitoring program, or the need to develop data that are consist-
ent with a historical database; however, historical approaches should not
be retained without careful evaluation of their ability to provide the data
necessary to make informed resource decisions in future years.
Periphyton, invertebrates, and fish spedes in a .stream vary in their
distribution among major habitats. Depending on the data quality objec-
tives established for the specific project or program, one or more assem-
blages may be targeted for inclusion in biosurvey activities. Attributes of
several potential assemblages and their several advantages were described
earlier in this chapter.
A major consideration in the development of bioassessment proce-
dures is whether sampling all habitats is necessary to evaluate biological
integrity or whether selected habitats can provide sufficient information.
The selection of single habitat over multiple habitat, or vice versa, influ-
ences study design and may influence selection of the biotic assemblage to
be sampled. Some taxa include individuals whose mobility or natural spa-
tial distribution requires multiple habitat sampling.
Generally, fish sampling reduces the need to make more detailed habi-
tat decisions because most fish in small to medium rivers can be sampled
using seines or electrofishing methods that efficiently sample all major
surface water habitats except hyporheic zones and bank burrows. By sam-
pling the full diversity of stream habitats for fish, the importance of fish
movements among microhabitats for resting and foraging is reduced. Effi-
cient sampling of all local habitats limits the problem of correcting evalua-
tions of taxa in case the intensity of sampling varies among the range of
available habitats.
Habitats to be sampled for periphyton require different analytical ap-
proaches. For example, periphyton assemblages may develop more easily
on rigid or hard substrates. Though periphyton can grow on the leaves and
stems of macrophytes, more prolific growths are generally seen on the hard
surfaces of large substrate particles (e.g., cobble or small boulders). Stein-
man and Mclntire (1986) found that substrate type is one of several charac-
teristics that affect the taxonomic structure of lotic periphyton assemblages.
Other factors are the dispersal and colonization rates of taxa in the species
pool, competitive interactions, herbivory, chemical composition of the envi-
ronment, and the character of ecological disturbances. Because it is difficult
to remove or collect periphyton from natural substrates (Austin et al. 1981),
hard surfaces (either natural or artificial) are usually the focus of sampling
efforts. Most strategies for sampling periphyton assemblages are single hab-
itat though other variables introduce additional complexity!
Benthic macroinvertebrates inhabit various habitats in lotic situations,
for example, riffles, pools, snags, or macrophyte beds. Complete character-
ization of the assemblage requires a multihabitat and multisampling
protocol such as that advocated by Lenat (1988). The benthic macro-
invertebrate protocols for rapid bioassessment advocated by Plafkin et al.
(1989) were developed for sampling the most productive and dominant
benthic habitat in wadable streams. Consequently, riffles and cobble sub-
strate were the primary focus of the rapid bioassessment protocols be-
cause that habitat is predominant across the country.
This approach works for small streams and streams that are domi-
nated by riffles; however, it requires additional evaluation and technical
-------
Conducting the Biosurvey
development for use in other habitats. Flafkin et al. (1989) argue that the
habitat where riffles predominate, wall often be the most productive and
stable habitat for the benthic community. The production of the habitat is
related to provision of refugia, food resources, and necessary community
interactions. It may be necessary to document the extent and character of
the habitat because streams differ in these qualities, which differences may
be, related to natural and anthropogenic causes. In some streams, riffles are
not a dominant feature, and the emphasis on them may be misleading;
Since the issuance of the Rapid Assessment Protocols (RBPs) in 1989,
rapid assessment techniques have evolved to focus on sampling of more
than one habitat type, usually in the proportion of their representation at
the sites of interest. These techniques have been primarily designed for
low gradient streams (Mid-Atlantic Coastal Streams Workgroup, 1993;
Florida Dep. Environ. Prot. 1994) and encompass the sampling of four or
five habitat categories.
The sampling of a single habitat type (e.g., riffles or runs) is intended
to limit the variability inherent in sampling natural substrates and to en-
hance the evaluation of attributes in an assemblage that will vary substan-
tially in various habitats. Double^ composited square meter kick net
samples (2 m2) are used in RBPs to collect large representative samples
from riffle or run areas. Other gear can also be used to collect such com-
posite samples.
Multihabitat sampling allows the evaluation of a broad range of effects
on the benthic assemblage. However, it may also introduce variability into
comparisons, of the benthic assemblage among sites. Multihabitat investi-
gations of water resource integrity are potentially confounded by (1) the
absence of a particular habitat at a station, and (2) the potential differences
in the quality and quantity of a habitat. As more habitats are sampled, the
more difficult it is to control for comparable habitat among sites; and the
absence of a habitat type at one or more stations exacerbates the problem.
However, some states, such as North Carolina, have been successful in
using a multihabitat sampling approach and advocate this technique as
being more appropriate than simply sampling the riffle or run (Lenat,
.1988). \
A case study in association with the North Carolina Department of En-
vironmental Management addressed the issue of sampling strategy and
indicated that the riffle assemblage and the multihabitat assemblage re-
sponded similarly to differences among stations (Plafkin et al. 1989): For
example, under stress, taxa richness was reduced by the same proportion
in both the riffle and the multihabitat assemblage samples at a given sta-
tion. These responses suggest that either the riffle assemblage or the multi-
habitat assemblage can be used to assess biotic integrity in streams in
which riffles are prevalent.
Kerans et al. (1992) examined patterns of variability and the contribu-
tion of pool versus riffle invertebrate samples to the evaluation of biotic in-
tegrity and the detection of different kinds of degradation. They evaluated
over a dozen attributes of the invertebrate assemblages including numbers
of species (total and for a number of taxa) as well as several ecological
classifications. At least eight attributes exhibited spatial or temporal
trends, or both, depending on whether the habitat was pools or riffles. At-
tributes that were temporally and spatially unpredictable included some
Several factors
related to habitat
selection should be
considered when
designing a
bioassessment
sampling strategy: (1)
target assemblage,
(2) single or multiple
habitat, and (3)
natural or artificial
substrates.
-------
"technical Guidance for Streams and Small Rivers
In either the single
habitat or multihabitat
approach, the most
prevalent and
physically stable
habitat that is likely to
reflect anthropogenic
disturbance in the
watershed should be
chosen.
i
The habitat with the
most diverse fauna is
preferred — riffles
followed by hard,
coarse substrates,
snags, aquatic
vegetation, and soft
substrates.
that are most commonly used in stream bioassessment. Kerans et al. con-
clude that measures of human impact on biotic integrity may be biased if
sampling is restricted to only one habitat
The choice of sampling habitats also entails a choice of sampling meth-
ods because conventional sampling methods for invertebrates vary in their
efficiency among habitats. Surber and Hess samplers are used for riffles/
while grab samplers are used most efficiently in the soft substrate of pool
habitats. Several forms of net samplers have been developed for various
stream habitats: kick nets or seines (Plafkin et at 1989; Lenat, 1988), D-
frame nets (Montana Dep. Health Environ. Sti., 1990), and slack (rectangu-
lar frame) samplers (Cuffney et al. 1993). Passive colonization-dependent'
samplers (e.g., Hester-Dendy samplers) may also be used for evaluation of
invertebrate assemblages (Ohio Environ. Prot Agency, 1987).
Substrate Choices
In either the single habitat or multihabitat approach, the most prevalent
and physically stable habitat that is likely to reflect anthropogenic disturb-
ance in the watershed should be chosen. These habitats will vary region-
ally-because' of differences in topography, geology, and climate. The
biological community in a particular stream may also change in response
to increasing stream size (Vannote et al. 1980). The key to sampling, perti-
nent to benthic invertebrate surveys, is to select the habitats that support a
similar assemblage of benthos within a range of stream sizes. Habitats that
have been used for benthos are riffles, snags, downed trees, submerged
aquatic vegetation, shorezone vegetation, and sediments, such as sand,
silt, or clay (Table 4-2). -
The habitat with the most diverse fauna is emphasized by most inves-
tigators because it offers the highest probability of sampling the most sen-
sitive taxa. Riffles usually fit this criterion, and when present, are
preferred! This habitat type is followed by hard, coarse substrates, snags,
aquatic vegetation, and soft substrates. If multiple habitats are selected,
similarity in habitat quality and comparable levels of effort among sam-
pling sites must be considered.
Tabl« 4-2.—Common benthlc habitats.
SNAGS/DOWNED TREES
SHOREZONE VEGETATION
Productive in biackwatar streams
(Bank* et al. 1984)
Diversity of ep'rfauna
Community dependent on
well-prepared substrate
• Present in most streams
• Measuros riparian impacts
• Dominated by shredders and collectors
• May be seasonal
SUBMERGED AQUATIC VEGETATION
SILT/MUD
Productive in coastal zones
High standing crop
Seasonal habitat
Snails usually abundant
Pool communities
DomlnatM by fauna
Sediment quality and water quality effects
Fauna uaually tolerant to tow oxygen
SHIFTING SAND
LEAF LITTER/DEBRIS
Prevalent in erosional areas
Dominated by opportunistic infauna
Sediment quality and water quality effects
High dominance by monotypic fauna
Prevalent in forested streams
Measures riparian impacts
Dominated by shredders
Microbia) preparation of substrate
-------
CHAPTER',:
Conducting the Biosurvey
Natural and Artificial Substrates
Most benthic surveys employ direct sampling of natural substrates. This
method is particularly important if habitat alteration is suspected as the
cause of impairment. A major assumption is that every habitat has a bio-
logical potential, which is reflected :in the resident biotic community. Be-
cause interpretation depends on the level of assemblage development
within the existing habitat, sampling natural substrates is recommended.
If, however, an artificial substrate cam be matched to the natural substrate
(e.g., using a rock basket sampler in a cobble substrate stream), men such
artificial substrates may also be used (So. Advis. Board, 1993). Maine uses
this rock basket approach. The Ohio EPA biooiteria program (Ohio Envi-
ron. Prot. Agency, 1987) has successfully used Hester-Dendy multiplate ar-
tificial substrate samplers supplemented by qualitative, natural substrate
samples to assess biological integrity using benthic assemblages.
The advantages and disadvantages of artificial substrates (Cairns,
1982) relative to natural substrates are the following:
• Advantages of Sampling with Artificial Substrates
1. Enhances sampling opportunities in locations that are difficult to
sample effectively.
2. Permits standardized sampling by eliminating subjectivity in
sample collection technique.
3. Minimizes confounding effects of habitat differences by providing
a standardized microhabitat
4. Directs the interpretation to specific water quality questions
without interference of habitat variability.
5. Increases the ease of placing samplers in discrete areas to discrimi-
nate impacts associated with multiple dischargers.
• Disadvantages of Sampling with Artificial Substrates
1. Requires the investigator to make two trips for each artificial
substrate sample (one to set and one to retrieve).
2. Measures colonization potential rather than resident community
structure.
3. Allows problems such as sampler disturbance and loss to occur.
4. Complicates interpretation of She effects of habitat structure.
If artificial substrates are selected, the surface area of the materials
should be standardized among units. Introduced substrates, in the context
of biological monitoring, are artificial substrates that are constructed to
match natural bottom materials at the site of the survey. An example of in-
troduced substrates are rock baskets, such as 'those used by Maine (Davies
et al. 1991), in which baskets that contain rocks native to the region of
known surface area are partially buried in the bottom sediment. Where
-------
Technical Guidance for Streams and Small Rivers
Production of and
adherence to
standard operating
procedures in all
phases offieldwork,
data analysis, and
evaluation, are
essential for
maintaining
consistency and
comparability among
datasets, overall
assessments, and for
appropriate quality
assurance and quality
control.
possible, the use of introduced substrate is preferable to other types of arti-
ficial substrate as recommended by the SAB (1993). Rock baskets or other
substrates should be placed in waters of similar depths, velocities, and
daily sun and shade regimes.
Standardization of Techniques
Standard operating procedures should be adhered to in all phases of field-
work, data analysis, and evaluation. They are essential for maintaining
consistency and comparability among data sets and for appropriate qual-
ity assurance and control (Kent and Payne, 1988; Klemm et al. 1990; Smith
et al. 1988). Without standard operating procedures to mimic previous
studies, the difficulties encountered in comparing temporal and spatial
data or analytic results may be substantial. Care must be taken to reduce
the inherent variability of the.sampling process (Cairns and Pratt, 1986)
through standardization of sampling gear, gear efficiency, level of effort,
subsampling methods, handling and processing procedures, and com-
puter software. Standardization of project activities provides considerable
strength in reducing, controlling, and understanding variability.
Sample Collection
A major influence on the comparability of field ecological projects is the
type and intensity of appropriate training and professional experience for
all personnel (Barbour and Thornley, 1990). Similar exposure to sampling
methods and standard operating procedures can reduce the amount of
variation from one sampling event or project to the next Standardizing the
equipment relative to operator efficiency, sampling effort, and the area to
be sampled greatly affects data quality. Operator efficiency depends on the
operator's experience, dexterity, stamina, and adherence to specified sur-
vey requirements. Physical habitat conditions at the time of sampling (e.g.,
flow levels, current velocity, and temperature) also influence efficiency. Ac-
tive sampling efforts (e.g., using net samples or electrofishing) may be
standardized as a function of person-hours spent at each sampling station
and by tracking the physical area or volume sampled. Passive methods
(e.g., artificial substrates, trap nets) may be standardized by tracking the
person-hours and the exposure time. This.choice is often dictated by the
earlier selection of the assemblage to be sampled; for some, a relatively
small selection of sampling techniques may be available. A certain sam-
pling area or volume may be required to obtain an appropriate sample
size from a particular community and to estimate the natural variability of
that community at the sampling station.
Once the assemblage, sampling equipment; and method have been cho-
sen, standard operating procedures can be written for field operations, in-
cluding a clear description of the sampling effort to be applied during each
sampling event. All employees should have this documentation, and new
employees should be accompanied in the field by experienced staff until they
are thoroughly familiar with all procedures (Ohio Environ. Prot Agency,
1987).
Processing samples in the field requires several critical steps. Sample
containers for benthic invertebrates and voucher fish should be marked
with appropriate and complete information on internal and external la-
-------
, .
Conducting the Biosurvey
be\s. Other identifying information and descriptions of visual observations
should be. recorded in a field notebook.
Data on birds and mammals, which consist primarily of visual obser-
vations and for which accurate field taxonomy is possible/ will not require
subsequent processing in the laboratory. However, the details of each ob-
servation should be carefully recorded so that they may be checked later.
Most fish sampling requires sorting, recording, and releasing the fish at
the site of capture. Fish sampling crews should have a reference collection
available in the field, and specimens should be collected and accurately la-
beled so that identifications can be confirmed.
Sample containers with preserved specimens should be assigned
unique serial or identification numbers. These numbers should be re-
corded in a logbook along with the appropriate labeling information. All
sample containers or specimens should be appropriately packaged for
transportation and continued processing in the laboratory.
For assemblages in which extremely large numbers of individuals or
associated substrate are obtained in each sample as is often the case with
small fish, benthic macroinvertebrates, periphyton, or planktonic orga-
nisms, it may be impractical ami-costly to process an entire sample. In
such cases, standardized random subsampling, similar to that recom-
mended by Plafkin et al. (1989), is a valid and cost-effective alternative.
As a subsampling method is developed, every attempt must be made
to reduce bias. Therefore, guidelines are needed to standardize the effort
and to eliminate investigator subjectivity. Rapid bioassessment protocols,
for example, maintain subsampling consistency by defining the mode (a
gridded pan), by placing limitations on the mechanics of subsampling and
the subsample size, and by assuring that the subsampling technique is
consistently random.
Sample Processing I
The need for specialized training and expertise is most necessary during
the identification of organisms. Unless the project objectives direct other-
wise, each specimen should be identified to the most specific taxonomic
level possible using current literature. Some technigiws may require iden-
tification only to the ordinal, familial, or generic level (Ohio Environ. Prot
Agency, 1987; Plafkin et al. 1989), but the most accurate information on tol-
erances and sensitivities is found at the species level.
Nevertheless, taxonomic resolution should be set at a level achievable
by appropriately trained state personnel State water resource agencies
should find it beneficial to establish collaborative working arrangements
with local and regional experts who can provide training, technical sup-
port, and quality assurance and control. Stream ecology research over the
last decade indicates that a specific minimal level of resolution should be
set (i.e., the "lowest achievable taxonomic level* is not a helpful criterion)
and that additional refinement should be left to individual state groups as
their capabilities permit (Sci. Advis. Board, 1993).
The SAB further states that proposed levels of intensity and taxonomic
resolution must receive a thorough evaluation (y'the scientific research
community. For example, adult and juvenile fish should usually be identi-
fiable by species (Sci. Advis. Board, 1993). The identification of larval fish
Standardized
random subsampling
is a valid and
cost-effective
alternative to
processing an entire
sample. Asa
subsampling method
is developed, every
attempt must be
made to reduce bias.
-------
BIOLOGICAL CRITERIA:
Technical Guidance for Streams and Small Rivers
may provide useful information; however, it may only be feasible to iden-
tify them to the generic or familial levels. Reasonable candidate levels for
stream macroinvertebrates are given in Table 4-3.
Table 4-3.—Proposal minimal lavala of taxonomlc resolution for atraam
maerolnvartabrataa (takan from 3d. Advta. Board, 1963).
TAXONOMIC LEVEL GROUPS
Wacoptara (in part). Ephamareptnm, Odonata, Trichoptara,
Magatoptara, Nauraplara. Lapktopteia, Cotaoptara (to part, tar-
vaa and aduttt). Hamiptara, Dlptom (TipuMaa and Shnuldaa),
Triba
CMronominaa
Subfamily
Chkonomidaa
Famly
Diptara (othar than Chlronomidaa, TipulWaa and SimuMdaa).
Oigochaata, Ptocoptara On part). Colaoptara (In part)
Ordar
Othar noninaaet groups
Once the samples have been analyzed (identified, enumerated, and
measured), reference (voucher) material should be placed in the well-
established network of federal, state, and university museums for region-
ally centralized curation (Sri. Advis. Board, 1993). This action ensures a
second level of quality control for specimen identification. Preferably, col-
lection and identification of voucher specimens will be coordinated with
taxonomic experts in regional museums. These repositories, which have
always been the centers for systematic^ should continue to be used for
this function (5d. Advis. Board, 1993). The SAB recommends that once the
information on the samples has been entered into a database and verified,
the repository institutions should be encouraged to conduct additional
systematic studies on the material. Information from these additional anal-
yses can then be made available to state biocriteria programs.
All identifications should be made using the most up-to-date and ap-
propriate taxonomic keys. Verification should be done in one of two ways:
(1) by comparison with a preestablished reference or research specimen
collection, or (2) by having specimens confirmed by taxonomic experts fa-
miliar with the group in question (Borror et al. 1989). A regional consensus
of taxonomic certainty* is critical to ensure that the results are comparable
both spatially and temporally. The taxonomists should always be con-
tacted by telephone or mail before any specimens are sent to their atten-
tion. It is also important to follow their advice on the proper methods for
packing and shipping samples. Damaged specimens may be useless and
impossible to identify.
Suggested Readings
Hart, D. (editor). 1990. Proc. Third Annual Ecological Quality Assurance Workshop. U.S.
Environ. Prot. Agency, Can, Min. Environ., Burlington, Ontario.
Karr, J.R. et al. 1986. Assessing Biological Integrity in Running Waters: A Method and Its
Rationale. Spec. PubL 5. Illinois Nat. History Surv., Urbana, IL.
-------
••• CHAPTER 4:
Conducting the Biosurvey
Memm, D.J., P.A. Lewis, F. Fulk, and J.M. Lazorchak. 1990. Macroinvertebrate Field and
Laboratory Methods for Evaluating the Biological Integrity of Surface Waters.
EPA/600/4-90-030. Off. Res. Develop., U.S. Environ. Prot Agency/Washington, DC
Mid-Atlantic Coastal'Streams Workgroup. 1993. Standard Operating Procedures and
Technical Basis: Macroinvertebrate Collection and Habitat Assessment for Low-gra-
dient Nontidal Streams. Draft Rep. Delaware Dtp. Nat Res. Environ. Conserv.,
Dover. ' .
Ohio Environmental Protection Agency. 1987. Biological Criteria for (the Protection of
Aquatic life. Volume 3: Standardized Biological Held Sampling and Laboratory
Methods for Assessing Fish and Macroinvertebrate Communities. Monitor. Assess.
Prog., Surface Water Sec, Div. Water QiiaL, Columbus, OR
. 1990. The Use of Bkxxiteria in the Ohio EPA Surface Water Monitoring and As-
sessment Program. Columbus, OR
U.S. Environmental Protection Agency. 1980b. Interim Guidelines and Specifications for
Preparing Quality Assurance Project Plans. QAMS-005/80. QuaL Assur. Manage.
Staff, Off. Resi Dev., Washington, DC.
. 1984c. Guidance for Preparation of Combined Work/Quality Assurance Project
Plans for Environmental Monitoring. Rep. OWRS QA-1. Washington, DC.
—. 1989. Preparing Perfect Project Plans. A Pocket Guide for the Preparation of
Quality Assurance Project Plans. EPAT600/9-89/087. Risk Reduction Eng. Lab., Off.
Res. Dev., Cincinnati, OR ..'..'
. 1990. Biological Criteria: National Program Guidance for Surface Waters. EPA-
440/5-90-004. Off. Water, Washington, DC.
-------
-------
CHAPTERS.
Evaluating
Environmental Effects
Should a biological survey reveal a significant departure from refer-
ence conditions or criteria, the next step is to seek diagnostic infor-
mation leading to remedial action. This entails the investigation of
an array of physical, chemical, and biological factors to determine the
likely source of degradation in the waiter resource.
Five major factors affect and determine water resource integrity (Karr
and Dudley, 1981; Karr et al. 1986). These factors are water quality, habitat
structure, flow regime, energy source, and biotic interactions. Monitoring
programs must integrate, measure, and evaluate the influences of these
factors (Fig. 5-1). A comprehensive discussion of all five and the enormous
variety of human actions that alter them is beyond the scope of this docu-
ment. We can, however, present a conceptual sketch of each one and how
it influences the integrity of the water resource. Several considerations are
involved in evaluating these complex factors.
Human actions often alter one or more of those factors and thus alter
the resident biota. Alterations may be obvious, such as the extinction of
species or the introduction of exotics, or they may be more subtle, such as
altered survival rates, reproductive success, or predation intensity. Protec-
tion or restoration of biotic integrity requires identification of the proc-
esses that have been altered by human actions. Careful evaluation of the
conditions in a study watershed can play a critical role in identifying the
potential causes of degradation. That: identification process is essential to
develop the most cost-effective approaches to improving the quality of
water resources.
Water Quality
The physical and chemical attributes of water are critical components of
the quality of a water resource. Because the earliest water resource legisla-
tion (e.g., the Refuse Act of 1899) dealt with disease and oil pollution in
navigable waters, emphasis has traditionally been on the physical and
chemical properties of water. Physical and chemical attributes of special
concern include but are not limited to temperature, dissolved oxygen, pH>
hardness, turbidity, concentrations of soluble and insoluble organics and
inorganics, alkalinity, nutrients, heavy metals, and an array of toxic sub-
Purpose:
To provide managers
with an understanding
of the factors that
affect and determine
water resource
integrity.
-------
BIOLOGICAL CRITERIA:
Technical Guidance for Streams and Small Rivers
Protection or
restoration of biotic
integrity requires
identification of the
processes that have
been altered by
human actions.
Careful evaluation of
the conditions in a
study watershed can
play z critical role in
identifying the
potential causes of
degradation. That
identification process
is essential to
develop the most
cost-effective
approaches to
improving the quality
of water resources.
ECOLOGICAL \
MPACTOF
HUMAfUNDUCED
ALTERATIONS I
1.En«rgySourc«
2. W**r Quality
3. Habitat Sftictura and Quality
4. Flow Rtgiirw
5. Biotic Interaction*
Figure M.—Five major classes of environmental factors that affsct aquatic biota In
lotlc systems. Right column lists selected expected results of anthropogenic pertur-
ballon (Karr et al. 1916).
stances. These substances may have simple chemical properties or their
dynamics may be complex and changing, depending on other constituents
in a particular situation including the geological strata, soils, and land use
in the region. The number of elements and compounds that influence
water quality is very large without human influences; with them, the com-
plexity of the problem is even greater. The human effects on biological
processes may be direct (i.e., they may cause mortality), or they may shift
the balance among species as a result of subtle effects, such as reduced re-
productive rates or changing competitive ability. Aquatic life use designa-
tions provide protection at various levels from the multitude of
anthropogenic effects.
The EPA encourages states to fully integrate biological surveys, whole-
effluent and ambient toxicity testing, and chemical-specific analyses to as-
-------
CHAPTERS:
Evaluating Environmental Effects
sess attainment or nonattainment of designated aquatic life uses in state
water quality standards (U.S. Environ. Prot Agency, 1991c). Ohio EPA
used numeric biological criteria within an existing framework of tiered
aquatic life uses to establish attainable, baseline expectations on a regional
basis (Yoder, 1991). Use attainment status in the Ohio water quality stand-
ards results in a classification of "full attainment," if all applicable numeric
biocriteria are met; "partial attainment," if at'least one aquatic assemblage
exhibits nonattainment but no lower than a 'fair" narrative rating; and
"nonattainment," if none of the applicable biocriteria are met, or if one as-
semblage reflects a "poor* or "very poor'narrative rating.
North Carolina's Department of Environment, Health, and Natural Re-
sources has used in-stream biota to assess water quality since the mid-1970s
(Overton, 1991), and the water quality regulations in the North Carolina
code have been revised to take biological impairment into account In addi-
tion, when fiscal realities in North Carolina required a more efficient water
quality program, all NPDES permits within a given river basin were sched-
uled to be issued within the same year (Overton, 1991). The same strategy
makes biological assessment more efficient because it can now focus on
specific river basins coincident with the renewal permits. Other states may
have to consider similar strategies tor-conserve resources.
The Maryland Department of the Environment, Water Quality Moni-
toring Division, uses biological assessment as part of a statewide water
quality monitoring network (Primrose et al. 1991). Using biological assess-
ment, Maryland has been able to differentiate among various degrees of
impairment and unimpainnent, and to distinguish particular water qual-
ity impacts.
the Arkansas Department of Polution Control and Ecology devel-
oped a bioassessment technique in the mid-1980s to assess the impact on
receiving waters from exceeding water quality-based limits (Shaekleford,
1988). Using its bioassessment approach as a screening tool, Arkansas fol-
lows a formal decision tree for assessing compliance with established
water quality limits (Fig. 5-2). The initial bioassessment screen may result
in the application of other biological, lexicological, or chemical methods.
After completion of screening, an on-site decision can be made for subse-
quent action. In situations where "no impairment" or "minimal impair-
ment" classifications are obtained, field efforts are reduced in frequency or
intensity until further information indicates a problem. Streams classified
as "substantially" or "excessively" impaired trigger additional investiga-
tive steps that employ an integration of methods (Shackleford, 1988).
The definitive evaluation of water quality impacts often requires ex-
pensive laboratory analyses. However,, careful review of conditions in the
watershed can provide early warning signals about the potential for water
resource degradation. For example, the presence of industrial, domestic,
and agricultural sources of chemical contaminants may be indicated by.
odors, froth, or colors in the water. These conditions should be noted dur-
ing field surveys for their potential diagnostic value.
* - , '
Habitat Structure
The physical structure of stream environments is critical to the ecological
health orjntegrity of lotic water resources. Attributes of significance to or-
ganisms in streams are channel morphology including width, depth, and
The EPA encourages
states to fully
integrate biological
surveys,
whole-effluent and
ambient toxicity
testing, and
chemical-specific
analyses to assess
attainment or
nonattainment of
designated aquatic
life uses in state water
quality standards.
Careful review of
conditions in the
watershed can
provide early warning
signals about the
potential for water
resource degradation.
-------
BIOLOGICAL CRITERIA:
Technical Guidance for Streams and Small Rivers
D« *^platt>
9M»4pKMe dirt
I
COtfUANCeUOHTOftlHOLEVB.
MmnMttonorComplm*
COMPLMWCC WSXC7KIN LEVEL
ofCer^mro.9MUK Ifcnd
ngu» 5-2.-0«d«lon matrix for application of rapid blbnaaaaamanta In Arkanaaa for
permitted point source discharge (ShacWaford, 1988).
sinuosity; floodplain shape and size; channel gradient; in-stream cover
such as presence of boulders and woody debris; substrate type and the di-
versity of substrates within a stream reach; riparian vegetation and the
canopy cover that it provides; and bank stability.
-------
', ; , CHAPTER 5:
Evaluating Environmental Effects
Channel morphology in natural watersheds is typically meandering with
substrate diversity created by varying velocities along and across the channel.
As a result, substrates are sorted to form pools and riffles that create horizon-
tal variation in the physical environment If a channel has been artificially
straightened and dredged (channelized), .temporal recovery will recreate sub-
strate diversity through vertical and lateral meandering processes (Hupp,
1992; Hupp and Simon, 1986). Because no stream channel is stable, a tempo-
ral dimension of diversity also exists. These physical attributes are closely
tied to other environmental conditions and impairments (Table 5-1).
Table 5-1.—Parameters that may be usoful In evaluating environmental condi-
tions and their relationship to geographic scales and the environmental factors
Influenced by human actions.
CATEGORY BY
GEOGRAPHIC SCALE
PARAMETER
ENVtRONUEirau.
FACTORS"
1. Watershed
Land use
Row stability1
Flow regime
Physical habitat
2. Riparian and Upper bank stabittyf:Ml Flow regime
bank structure Sank vegetative stability*1'-81 Energy base
. Woody riparian vegetation" ' Physical habitat
—•species identity ,
—number of species
Grazing or other disruptive pressures*'
Streamside cover (% vegetation)*-1
Riparian vegetative zone width*1'
Streambank erosion'
3. Channel
morphology
Channel alteration**'
Bottom scouring*
Deposition*
Pool/riffle, run/bend ratio*-*
Lower bank channel capacity*
Channel sinuosity*-'*
Channel gradient?-*
Bank form/bend morphology"
Flow regime
Energy base
Biotie interactions
Water quality
Physical habitat
4. In-stream.
Substrate composition/size; % rubble,
gravel, submerged logs, undercut
banks, or other stable habitat*-*-"*'
% pools'
Pool substrate charactnrization*
Pool variability'
% embeddedness of gravel, cobble,
. and boulder parttelai by fine sediment;
sedimentation**1'
Rate of sedimentation
Ftowrate*1"
Velocity/depth*-**
Canopy cover (shading)*-'
Stream surface shading (vegetation,
cliffs, mountains, undercut banks,
togs)"1*' .
Stream width0-" ,
Water temperature6
Flow regime
Energy base
Biotie interactions
Water quality
Physical habitat
REFERENCES:
•Plafkin et al. 1989
"Plans et al. 1987
'Plans et al. 1983; Armour at al. 1983
"Rankin, 1991
•Gorman. 1988
'Osbome et al. 1991
'Barton el: al. 1985
"Hupp and Simon, 1936; 1991
'Karr and Dionne, 1991
iKarr. 1991 •
-------
Technical Guidance for Streams and Small Rivers
An assessment of
habitat structure is
critical to any
evaluation of -
ecological integrity.
Habitat assessment
provides information
on habitat quality; it
also identifies obvious
constraints on the
site's potential to
achieve attainment,
assists in the
selection of
appropriate sampling
stations, and provides
basic information for
interpreting biosurvey
results.
The influence of habitat structure spans the range from regional geog-
raphy to the pattern of interstitial spaces between rocks in the river sub-
strate. Habitat structure on all scales is critical to the biology of most
stream organisms, and subtle or massive habitat alteration on any scale
may influence the quality of the water resource.
The influence of habitat structure on the aquatic community causes
natural variability even in undisturbed communities. Understanding the
relationship of expected trends in biological condition as a result of
changes in habitat structure is an important feature of biological assess-
ments. Ohio EPA found that their measurement of habitat quality, the
Qualitative Habitat Evaluation Index (QHEI), was significantly correlated
with the Index of Biotic Integrity (IBI) in Ohio streams (Fig. 5-3) with r -
0.47 (Rankin, 1991) on a broad scale over the state. Ranldn also found that
stream habitat quality and land use at various geographic scales are im-
portant influences on fish assemblages and that relatively intact stream
habitat throughout the drainage can compensate for short stretches of
poor habitat In contrast, however, habitat-sensitive species may be re-
duced or destroyed in stream basins with extensive degraded conditions,
even if short stretches of good habitat exist. The Maryland Department of
the Environment, using the relationship between habitat structure and bio-
logical condition, demonstrated effects from various influences (Fig. 5-4)
including agricultural runoff, treatment plant effluent, channelization, and
landfill operations (Primrose et al. 1991).
Habitat Quality and Biological Condition
The variability of environmental conditions directly affects patterns of life,
population, and the micro- and macrogeographic distribution of org?.-
nisms (Cooper, 1984; Price, 1975; Smith, 1974). An assessment of habitat
structure is therefore critical to any evaluation of ecological integrity (Kan
et aL 1986; Plafkin et al. 1989). Habitat assessment provides information on
Point Size is Related
to Number of Data
Points Overlapping
50 60
QHEI
Figure 5-3.-Qualltatlve Habitat Evaluation Index (QHEI) veraua the index of Blotlc In-
tegrity (IBI) for 465 relatively unlmpacted and habitat modified Ohio stream sites
(Rankln, 1991).
-------
Evaluating Environmental Effects
a
5
1
100-
90-
80
70-
60-
50
40
30-
20-
10-
0
1 ,
Unimpatrtd
Mod*nMty
Irnpvrad
54V
-------
BIOLOGICAL CRITERIA:
Technical Guidance for Streams and Small Rivers
Gradient is perhaps
the most influential
factor for segregating
a totic waterbody
because it is related
to topography and
landform, geological
formations, and
elevation, which in
turn influence
vegetation patterns.
Implementation of
water quality
improvements can be
independent of
habitat quality, but
judgment of the
improvement in
bblogical integrity
cannot.
potential cause of reduced biotic condition. If habitat structural differences
result from the natural landscape rather than human interference, then the
possibility that an inappropriate reference condition was used must be
considered.
The habitat assessment approach outlined here (Barbour and Stribling,
1991; Plafkin'et aL 1989) is applicable to wadable streams and rivers. Be-
cause fish and benthic macroinvertebrates are the focal points of these rec-
ommended bioassessment procedures, habitat structural parameters were
chosen that influence the development of these communities. Although
streams across the country exhibit a wide range of variability, some gener-
alizations can be made Gradient is perhaps the most influential factor for
segregating a lotic waterbody because it is related to topography and land-
form, geological formations, and elevation, which in turn influence vegeta-
tion patterns. Four generic stream categories related to gradient can be
identified: mountain, piedmont, valley plains, and coastal plains. Several
habitat attributes serve as a framework for assessing habitat quality:
* Substrate variety/in-stream cover
• Bottom substrate characterization/embeddedness
• Flow or velocity /depth
• Canopy cover (shading)
• Channel alteration
• Bottom scouring and deposition
• Pool to riffle and run to bend ratios, channel sinuosity
• Lower bank channel capacity
• Upper bank stability
• Bank vegetative stability (grazing or other disruptive pressure)
* Streamside cover
• Riparian vegetative zone width
While the investigator is on-site, the quality of each parameter can be
assessed. First, numeric value from a scale based on a gradient of condi-
tions is assigned to assess the quality of each parameter. Then, a composite
of information from each parameter is compared to a reference condition.
Such a quantified assessment of habitat structure provides a more mean-
ingful interpretation of biological condition. Habitat assessment incorpo-
rates information on stream segments or reaches. However, a linear
relationship between site-specific quality of habitat and community per-
formance may not exist to the point that habitat structural condition can
be used to "predict" biological performance with accuracy.
If habitat degradation has occurred, mitigation or improvement of the
habitat through stream restoration activities should be evaluated. Imple-
mentation of water quality improvements can be independent of habitat
quality, but judgment of the improvement in biological integrity cannot.
Flow Regime.
Fluctuating water levels are an integral part of the stream ecosystem, and
the biota are dependent on seasonal flow variation. High flow events are
especially important in maintaining the habitat complexity of pools, riffles,
-------
** . , .
Evaluating Environmental Effects.
clean substrates, and bars (Hill ct'al. 1991). Aquatic organisms have
evolved to compensate for changing now regimes, even periodic cata-
strophic flow conditions. High water periods are determined by the fre-
quency, occurrence, and type of precipitation event as well as antecedent
conditions such as soil moisture, time since last rain, and amount and type
of soil cover. Dewatering the channel lor major periods as a result of
human actions is dearly a degradation of the water resource, but more
subtle changes in the volume and periods of flow may have equally devas-
tating effects on the resident biota.
Jones and dark (1987) discuss the effects of urbanization on the funda-
mental hydrology of watersheds and the natural flow regime. Increases in
impervious surface area (e.g., roads, parking lofts) result in a substantial in-
crease in the proportion of rainfall that is rapidly discharged from the wa-
tershed as direct runoff and streamflow. Such runoff increases the volume
of flood flows and instances of channel instability. Leonard and Orth
(1986) developed a cultural pollution index to evaluate the health of the
fish community subject to. the effects of road density, population encroach-
ment, mining, and organic pollution. These effects have substantial influ-
ence on flow regime. Steedman (1988) also evaluated the condition of fish
communities in heavily urbanized areas of Ontario. He found that certain
attributes that are relatively sensitive to urbanization effects can serve as
pertinent response, signatures.
Ohio EPA found that the presence or absence c/channelization influ-
enced the relationship between the quality of habitat structure and the
condition of the fish community (Ohio Environ, Prot. Agency, 1990); In the
absence of channelization, for example, Twin Creek and Kokosing River
(Fig. 5-5) had high IBI values, even in the presence of sporadic degraded
habitat. In these instances, the relatively good habitat quality throughout
the watershed supported the fish community in short reaches of degraded,
habitat (Rankin, 1991). In channelized lotic systems, for example, Tiffin
River and Little Auglaize River (Fig. 5-5), the best habitats were degraded
and IBI scores remained essentially unchanged as the habitat was de-
graded further. The quality of habitat structure and the flow regime are in-
tricately associated. In areas of extensive channelization, communities may
consist only of generalists and opportunists able to withstand harsh flow
conditions directly, or the secondary effects of fthosf flow conditions (e.g.,
reduced abundance of food or presence of habitat refuges).
• Effects of Channelization. Unchannelized or otherwise unmodified
streams have normal, low-level, and mostly consistent rates of sediment
deposition on the bed and low, convex banks. The channel usually has
some degree of meandering, and the banks lose very little mass during ei-
ther low or high flows.
Efforts to control flooding and to drain wetlands often involve chan-
nelization of streams to provide more rapid removal of water. Unfortu-
nately, these activities create unstable channels with higher gradients and
without meanders. Hydrogeomorphic processes tend to restore the dy-
namic stability of these systems over time (Hupp and Simon, 1991). The
stream continuum hypothesis (Vannote et al. 1980) depicts the stream as
an upstream-downstream gradient of gradually -changing physical condi-
tions and associated adjustments in functional attributes of the biota.
Fluctuating water
levels are an integral
pan of the stream
ecosystem, and the
biota are dependent
on seasonal flow
variation.
-------
BIOLOGICAL Cfit JKHIA;
Technical Guidance for Streams and Small Rivers
m
60
50
40
30
20
10
• TWINCFL
A TIFFIN Ft.
A LAUGLMZEFL
O KOKQSINGFL
8
0 10 20 30 40 50 60 70 80 90 100
QHEI
Figure 54.—Relationship of the Indue of Blotlc Inttgrlty (IBB) to change* In the quality
of habitat structure through the Qualitative Habitat Evaluation Index (QHEI) In chan-
nelized (triangles) and unehannellzed (circle*) (Ohio Environ. Prot Agency, 1990).
Biological processes in downstream areas are linked to those in up-
stream areas by the flow of water, nutrients, and organic materials' Be-
cause channelization produces an increase in flow velocity or scour, active
bed degradation occurs, causing the movement of substrate particles
downstream. As bed degradation continues, degradation of lower
streambanks begins, eventually producing bank failure and concave up-
ward banks. During this period of severe instability, the channel is rapidly
(in a geologic sense) becoming wider and the water level shallower, some-
times producing a braided flow pattern. Channel widening causes persist-
ent bank failure in the downstream areas and results in losses of canopy
cover and detrital input. These degradation processes move upstream, re-
ducing the rate of channel widening and providing depositional sediment
in downstream areas. ».
Hydrological processes in channelized stream!* have direct effects on
the substrate (embeddedness, scour, and particle size distribution). Trans-
ported sediment causes aggradation to occur downstream with deposition
on the bed and at the bases of banks. Accretion occurs on the banks with
the beginning of the stabilization processes, and seed supplies from ripar-
ian vegetation or windblown from other areas settle on these deposits. As
vegetation, particularly woody species, becomes established on bank de-
positional surfaces, stability increases. During this phase of the channel re-
covery process, meandering features develop through deposition and
vegetative stabilization of point bars (inside bend). The return of disturbed
stream channels to a dynamically stable, meandering morphology results
primarily from the aggradation of banks and beds and the establishment
of riparian stands of woody vegetation (Hupp, 1992; Hupp and Simon,
1986,1991; Simon and Hupp, 1987). Hupp (1992) has estimated that an av-
erage of 65 years is* needed for this recovery process in nonbedrock con-
trolled, channelized streams in west Tennessee.
-------
Evaluating Environmental Effects
A complete concrete lining of natural waterways in western states has
long been Used to control wet weather flooding. Low flows of reclaimed
water are the only source of water for most of the year in these "streams *
Wet weather flows are commonly enormous and rapid. Though technically
listed as streams and rivers, these engineered channels do hot dearly fit def-
initions commonly understood for either "aquatic habitat" or "streams."
• Effects of Flow Regulation. Many streams are characterized by highly
variable and unpredictable flow regimes (Bain et al. 1988). Aquatic
macrophyte stands have been shown to be affected by current velocity, but
the degree and manner varies with the size of the channel (Chambers et aL
1991). In regulated streams, the importance of a bank-to-midstream habitat
orientation becomes magnified. Flow changes displace the shallow shore-
line zones, forcing fish restricted to these areas (small fish that use shallow,
slow microhabitats) to relocate to maintain their specific set of habitat con-
ditions (Bain et al. 1988). Therefore, if shallow-water habitats are unstable
and unable to sustain a well-balanced assemblage, then the functional
value of the assemblage is lost and a reduction in organismal population
density may follow. .
Gislason (1985) illustrates a similar pattern for aquatic insect distribu-
tion in fluctuating flows. Bain et al. (1983) also suggest that without the
functional availability of shallow, slow, shoreline areas, the stream envi-
ronment becomes one general type of unstable habitat, dominated by a
few habitat generalists and those species using mostly mid-stream habi-
tats. In these cases, the dominance of generalists confounds the assessment
of contiguous impact types such as nonpoint source runoff and point
source discharges. Comparison of historical and current flow conditions
can provide valuable information about the extent to which flow alteration
is responsible for degradation in biological integrity.
Energy Source
Stream organisms have evolved to accept and use the energy available to
them in natural watersheds. For most small or headwater streams in for-
ested areas of North America, a period of major leaf fall occurs in the au-
tumn. Leaves, in a form referred to as coarse particulate organic matter
(CPOM), reach the water and are quickly colonized by bacteria and fungi.
The organisms then provide food for invertebrates, which are in turn eaten
by fish and other vertebrates. The relative balance of production and respi-
ration varies as a function of stream size, according to the stream contin-
uum hypothesis (Vannote et al. 1980).
Human alteration of the source, type, and quantity of organic material
entering streams can affect biological integrity in many ways. Natural
shifts in the energy base occur along stream and river gradients, thus pro-
viding a major dimension of resource partitioning for the aquatic commu-
nity. The stream continuum concept (Vannote et al. 1980) outlines different
attributes of communities as the energy base shifts from heterotrophic (ex-
ternal) to autotrophic (internal) inputs. These shifts are generally related to
increases in drainage area catchments, but exceptions do.occur-that are re-
lated to localized conditions.
Along the stream/river gradient (Fig. 5-6), Cummins (1983) describes
the measurement of this shift as a photosynthesis/respiration (P/R) ratio.
Comparison of
historical and current
flow conditions can
provide valuable
information about the
extent to which flow
alteration is
responsible for
degradation in
biological integrity.
-------
BIOLOGICAL CRITERIA:
Technical Guidance for Streams and Small Rivers
Alterations to the
energy base are not
independent of
alterations to habitat
structure. In many.
instances,
assessment of habitat
quality is an
assessment of
impacts to the energy
base.
This P/R ratio is less than 1 in the headwater areas of streams and large
rivers. Therefore, these reaches are heterotrophic because in-stxeam photo-
synthesis is not a primary energy source. The P/R ratio is greater than 1 in
the mid-sized rivers where in-stream photosynthesis is a major contributor
to the energy base; the latter are autotrophic The removal of riparian veg-
etation for agriculture, channelization, or strip mining, or the shift from
natural riparian flora to introduced species for urbanization projects alters
the energy base of the aquatic system. Although the stream continuum is
thought to no longer hold true for the majority of watersheds, it does ex-
emplify the important considerations in energy base and aquatic ecosys-
tem interaction.
tr
UJ
o
oe
o
UJ
£E
I—
CO
3
-------
1 • ; . l^tlAr-' -n s.
Evaluating Environmental Effects
Alterations to the energy base are not independent of alterations to
habitat structure. In many instances, assessment of habitat quality is an as-
sessment of impacts to the energy base. However, the evaluation of
changes in the energy base can be strengthened by a systematic riparian
assessment based on a delineation of natural flora. Alterations in the spe-
cies of riparian plants influence the functional representation of the
aquatic trophic structure biota.
Wilhelm and Ladd (1988) developed a basic tool for conducting natu-
ral area assessments in the Chicago region. They presented a checklist of
vascular plants of the Chicago region and assigned each species a coeffi-
cient of conservatism. This measure expresses the value of the species rela-
tive to all other elements in the flora and its particular tie with ancestral
vegetation. Low scores are given to native species that are relatively ubiq-
uitous under a broad set of disturbance conditions; high scores are given
to species that are sensitive to disturbance; and ho scores are assigned to
non-native species. In this manner, vegetation can be assessed as repre-
senting natural or disturbance conditions.
Applying this method to riparian corridors would require a similar
classification of vegetation. However, much literature is available to aid in
classifying riparian flora. The U.S. Forest Service has compiled an exten-
sive database on riparian systems that has been published in several re-
ports (e.g., Platts et al. 1983). Hupp and Simon (1991) recognize early
successional species of woody vegetation in riparian zones of disturbed
and recovering stream channels in western Tennessee. Padgett et aL (1989)
provide a substantial list of references documenting vegetation classifica-
tion in many of the western states.
Biotic Interactions
Predation, competition, disease, and mutualistic interactions influence
where and when species occur within, streams. Larval stages of mussels,
for example, must attach to the gills of specific fish species to complete
their life cycles. Stream communities are often dominated by a few
"strongly interacting" species that may have disproportionate effects on
the other members of the community (Hart, 1992; Power, 1990). The addi-
tion of human influences may alter the integrity of these interactions in
ways that alter the abundances of local species and may even cause their
demise. Additional human influences are harvests for sport and commer-
cial purposes and the introduction of exotic species, sometimes intention-
ally but often inadvertently. The practice of stocking fish can be an
ecological or genetic disturbance, especially if naturally occurring popula-
tions are replaced or infiltrated by stocked individuals. However, the ac-
ceptance of this practice is an important societal decision; its advantages
and disadvantages must be carefully weighed.
Cumulative Impacts
Even when human actions have an influence on only one of these factors,
the effect may cascade through several others. For example, clearing land
for agriculture alters the erosion rate and thus the extent to which sedi-
mentation may alter the regional biota. Removal of natural vegetation re-
-------
BIOLOGICAL CRITERIA.
Techn!csl Guidance for Streams and Small Rivers
The diversity of
influences on the
quality of water
resources requires
the kind of multipfe
attribute approach
common to recent
biocriteria program
efforts. The use of a '
multiple attribute
approach enables the
development of
biological response
signatures to assess
probable "causes and
effects.'
duces shading, water infiltration, and groundwater recharge, thereby in-
creasing water temperatures, insolation, and the frequency of flood and
drought flows. The resultant agricultural activities may change the stream
through channelization/and thus further influence habitat structure. Alter-
ations in the land cover and the channel often have major impacts on
water quality (e.g., increased amounts of nitrogen and phosphorus in the
runoff from agricultural fields or pesticides in the water). Excess nutrients
in modified channels exposed to ample sunlight will enhance the growth
of nuisance algae, especially during summer's low flow periods..
Unfortunately, human influences on stream ecosystems cannot be eas-
ily categorized (Karr, 1991). The dose association between alteration of
habitat structure and other impact types complicates the determination of ,
'cause and effect" However, this dimension becomes paramount when
mitigative measures are crucial to the attainment of designated uses or
biocriteria. In many cases, deductive reasoning, thorough review of the bi-
ological data, and use of biological response signatures supported by other .
environmental data (Le., physical characterization, toxidty testing, and
chemical analyses) aid the assessment of impairment.
The_unplications of significantly altered systems, for example, chan-
nelized streams in urban areas or stream flows regulated by hydroelectric
dams, are that reference conditions different from the natural system may
have to be established to represent these systems and to evaluate other im-
pact types (Karr and Dionne, 1991). When major impacts (Le., significant
habitat alterations) are present; it is difficult to adequately evaluate
changes in community elements and processes that may be attributable to
other impacts.
The diversity of influences on the quality of water resources requires the
kind of multiple attribute approach common to recent biocriteria program ef-
forts. The use of a multiple attribute approach enables the development of bi-
ological response signatures to assess probable "causes and effects."
Using biological response signatures, the Ohio EPA (Yoder, 1991) was
able to assign each of their more severely degraded situations to one of six
groups:
• complex municipal and industrial wastes,
• conventional municipal and industrial wastes,
• combined sewer overflow and urbanization,
• channelization,
• agricultural nonpoint source, or
• other, often complex, impacts.
The Ohio EPA also found that various impact types may have one or
two biological response characteristics in common. In rare cases, they have
three in common. Therefore, only a multiple assemblage, multimetric ap-
proach enables a differentiation among impact types. In certain cases, the
severity of the impact is related to the type of impact. The IBI has been
used by Ohio EPA to characterize these impact types (Fig. 5-7).
-------
Evaluating Environmental Effects
60
IMP ACT TYPE
• •GRADIENT*
BIOLOGICAL RESPONSE
50 H
I 40 r
B
I
30f
20
10
UTlpactad.
STREAM/
IMPACTS
EXCEPTIONAL
Conations
Miner swinge and
, meat agneultural
NPS imoacei
nwntsiitaitenjew
DO.habiiat impacts
CSCVUf&an impacts.
UMUHC toacity
Complex tone
(acutt). acid mint.
tone 3»dimena
i I BIS OARSYCR. I
(Municipal Agr. 1
NPS) I
WALNUT CH.
(Industrial^
Conventional.
Municipal)
HOCKING R.
(MunicipiJ wPra-
tieanwm,CSO)
RUSHCR.
(AcidMn*
Oninag*)
RIVER MILE
Rgur« 5-7.—Biotoglead community response M portrayed by the Indtx of Blotte In.
tvgrlty 0BQ In four slmlivly tlzwl Ohio riwra with dlffwwit type* of point and non-
point source Impact* (Yoder, 1991). .
Suggested Readings
Atkinson, SJF. 1985. Habitat-based methods ibr biological impact assessment Environ.
Prof. 7:26532.
Bain, M.B., J.T. Him, and HE. Booke. 1988. Streamflow regulation and fish community
stmcture. Ecology 69(2)382-92.
Ball J. 1982. Stream classification guidelines tot Wisconsin. In 1983 Water Quality Standards
Handbook. Oft Water Reg. Standards, US. Environ. Prot Agency, Washington, DC
Barbour, M.T. and J.B. Stribling. 1991. Use of habitat assessment in evaluating the biological
integrity of stream communities. Pages 25-38 in Biological Criteria: Research and Regu-
lation. EPA 440/5^1-005. Off. Water, US. Environ. Prot Agency, Washington, DC
Karr, J JL et al. 1986. Assessing Biological Integrity in Running Waters: A Method and Its
Rationale. Spec. PubL 5. Illinois Nat History Surv., Urbana, IL.
Karr, JJL 1991. Biological integrity: a long-neglected aspect of water resource manage-
ment EcoLAppL 1:66-84. . , •
Leonard, P.M. and D.J. Orth. 1986. Application and testing of an index of biotic integrity
in small, coolwater streams. Trans. Am. Fish. Soc. 115:401-14.
Ohio Environmental Protection Agency. 1990. The Use of Biocriteria in the Ohio EPA
Surface Water Monitoring and Assessment Program. Columbus, OH
Platts, WJS., W1F. Megahan, and G.W. MirishalL 1983. Methods for Evaluating Stream,
Riparian, and Biotic Conditions. Gen. Tech. Rep. INT-138. Intermountain Res. Sta.,
Forest Serv., US. Dep. Agric., Ogden, UT.
Steedman, R.J. 1988. Modification and assessment of an index of biotic integrity to quan-
tify stream quality in southern Ontario. Can. J. Fish. Aquat. So. 45:492-501.
. Environmental Protection Agency. 1983. Technical Support Manual: Waterbody
Surveys and Assessments for Conducting Use Attainability Analyses. VoL 1-3. Off.
Water Reg. Stand., Washington, DC
1990. Biological Criteria: National Program Guidance for Surface Waters. EPA-
440/5-90-004. Off. Water, Washington; DC
A multiple
assemblage,
multimetric approach
enables a
differentiation among
impact types.
-------
\
-------
CHAPTERS.
Multimetric Approaches
forBiocriteria
Development
C' ' . ' - ~ 1
lassical approaches to the assessment of biological integrity have
usually selected a single biological attribute that refers to a narrow
range of perturbations or conditions (Kan et al. 1986). Likewise,
many ecological studies have focused on a limited number of parameters,
such as species distributions, abundance trends, standing crops, or pro-
duction estimates, which are interpreted separately, then used to provide a
summary statement about the system's overall health. These approaches
are limited because a single attribute may not reflect the overall ecological
health of the stream or region. An accurate assessment of biological integ-
rity requires a method that examines the pattern and processes of biotic re-
sponses from individual to ecosystem levels (Karr et al. 1986).
An alternative approach is to define an array of metrics, each of which
provides information on a biological assemblage and, when integrated,
functions as an overall indicator of the stream or river's biological condi-
tion. The strength of a multimetric assessment is its ability to integrate in-
formation from individual, population, community, and ecosystem levels
and evaluate this information, with reference to biogeography, as a single,
ecologically based index of water resource quality (Karr, 1991; Karr et al!
1986; Plafkin et aL 1989). Multimetric assessments provide detection capa-
bility over a broad range and nature of stressors. The Ohio EPA (1987) sug-
gests that the strengths of individual metrics taken in combination
minimize any weaknesses they may have individually.
Abel (1989), LaPoint and Fairchild (1989), and Karr (1991) do not rec-
ommend using a single metric For the broad range of human impacts, a
comprehensive, multiple metric approach is more appropriate. Similarly,
each of the assemblages discussed in Chapter 4 has a response range to
disturbing events and 'impairments (degraded conditions). Therefore,
biosurveys that target multiple assemblages provide the detection capabil-
ity that is needed to accomplish assessment objectives.
Karr (1991), Karr etal. (1986), Ohio EPA (1987), and Plafkin etal. (1989)
recommend use of a number of biological assemblages and metrics that
can, when combined and compared with expected conditions/give a more
complete picture of the relative biological condition of the study site.
Purpose:
To describe a
multimetric approach
for analyzing
biological data and to
provide guidance for
regional selection of
metrics.
The accurate
assessment of
biological integrity
requires a method
that examines the
patterns and
processes of biotic
responses from
individual to
ecosystem levels.
-------
BIOLOGICAL CRITERIA.
Technical Guidance for Streams and Small Rivers
A biological attribute
or metric is some
feature or
characteristic of the
blotio assemblage -.
that reflects ambient
condition, especially
the influence of
human actions.
Metric Evaluation and Calibration
Core metrics should represent diverse aspects of structure, composition/
individual health, or processes of the aquatic biota. Together they form the
foundation for a sound integrated analysis of the biotic condition and
judge of the system's biological integrity. Thus, metrics reflecting commu-
nity characteristics are appropriate in biocriteria programs if their rele-
vance can be demonstrated, their response range verified and
documented, and the potential for program application exists. Regional
variation in metric details are expected; nevertheless, the general princi-
ples used to define metrics seem consistent over wide geographic areas
(Miller etaL 1988).
Candidate metrics are determined from the biological data. Good met-
rics have low variability with respect to the expected range and response of
the metrics: it must be possible to discriminate between impaired and un-
impaired sites from the metric values. The use of percentiles is a useful tech-
nique to evaluate variability of metric performance within stream classes. In
operational bioassessment, metric values below the lower quartile of refer-
ence conditions are typically judged impaired to some degree (e.g., Ohio En-
viron. Frot Agency, 1990). The distance from the lower quartile can be
termed a "scope for detection" (Fig. 6-la). The larger this distance, com-
pared to the interquartile range, the easier it is to detect deviation from the
reference condition. Thus, we can define a "detection coefficient" as the
ratio of the interquartile range to the scope for detection (Gerritsen and
Bowman, 1994). This coefficient is analogous to the coefficient of variation
(CV), and the smaller the value, the easier it is to detect the impairment
Metrics with high variability, or scope for detection, compared to the
range of response should be used with caution. Many metrics (e.g., num-
ber of taxa) decrease in value with impairment and the detection coeffi-
cient for reference sites is thus a good measure of the metrics' potential
discrimination ability. Some metric values (e.g., HBI, percent omnivores,
Max
Min
maximum
75th percentOe
median
25th percsntile
minimum
T
T
interquartile
range
scope for
detecting
mpairrnent
Figure 6-to.—Metrics that decrease with Impairment
-------
Multimetric Approaches for Biocriteria Development
100%—
0%
T
scope for
detecting
impairment
interquartile
range
T
Flgura«.1b.—Metric* that IncrMM with ImpirirmMt
percent filterers) may increase under impaired conditions, and the scope
for detection would be from the 75th percentile to the maximum value
(Fig. 6-lb). The detection coefficient would be calculated the same way
and used to judge the discriminatory power of the metrics.
Certain metrics may exhibit a continuum of expectations dependent
on specific physical attributes of the reference streams. For example,
Fausch et al. (1984) determined that the total number of fish species
changes as a function of stream size estimated by stream order or water-
shed area (Fig. 6-2). They showed that when these data are plotted, the
points produce a distinct right triangle, the hypotenuse of which approxi-
mates the upper limit of species richness. Thus, a line with a slope fitted to
include about 95 percent of the sites is an appropriate approximation of a
maximum line of expectations for the metric in question and identifies the,
upper limit of the reference condition. The area on the graph beneath the
maximum line can then be trisected or quadrisected to assign scores to a
range of metric values as illustrated in Figure 6-2. The scores provide the
transformation of values to a consistent: measurement scale to group infor-
mation from several metrics for analysis. .
When different stream classes have different expectations in metric
values and a covariate that produces a monotonic response in a metric, a
plot of survey data for each stream class may be useful (Fig. 6-3). For each
metric, the sites are sorted by stream class (e.g., ecoregion, stream type)
and plotted to ascertain the spread in data and the ability to discriminate
among classes (Fig. 6-4). If such a representation of the data does not allow
discrimination of the classes, then it will not be necessary to develop a sep-
arate biocriterion for each class. That is, a single criterion will be applica-
ble to a set of sites that represent different physical classes. Conversely, if
differences in the biological attribute are apparent and appear to corre-
spond to the classification, then separate criteria are necessary. This tech-
nique is especially useful if the covariates are unknown or do not east, but
a difference in stream class is apparent (Fig. 6-4).
Core metrics should
represent diverse
aspects of structure,
composition,
individual health, or
processes of the
aquatic biota.
-------
•i ,!>
3.CLOGICAL CRITERIA
Technical Guidance for Streams and Small Rivers.
30—
20—
10—
Maximum Species
Richness Line'
T
2
T
3
T
4
T
5
T
" — - Stream Order
Figure 6-2.—Total number of fish species vsreus stream order for 72 sHes along the
Embarras River In Illinois (Fausch et al. 1984).
(e.g., Stream S!z»)
Figure 6-3.—Metrics plotted with a continuous covarlate (hypothetical example).
Pilot studies or small-scale research may be needed to define, evaluate,
and calibrate metrics. Past efforts to evaluate the use of individual metrics
illustrate procedural approaches to this task (Angermeier and Karr, 1986;
Harbour et al. 1992; Boyle et al. 1990; Davis and Lubin, 1991; Karr and
Kerans, 1992; Karr et al. 1986; Kerans et al. 1992; Lyons, 1992; Resh and
Jackson, 1993). Metrics can be calibrated by evaluating the response of
metric values to varying levels of stressors.
Sites must be carefully selected to cover the widest possible range of
suspected stressors. In general, impaired sites are selected that have im-
pacts from stressors singly and in combination. The selected impaired sites
-------
, .
Multimetric Approaches for Biocriteria Development
VMll
Stream Class
Figure 6-4.—Box and whisker plot* of metric valuu from hypothetical strum
classes. Shaded portions ars above the median for each class. The box represents a
pereentlle, the vertical line la 1.5 times the interquartile ranaa, and the horizontal line
la the median of each distribution.
' '" "
and the reference sites together are the basis for developing an empirical
model of metric response to stressors. Categories of land uses equated
with potential impairment are listed in Chapter 7. Candidate metrics that
do not respond to any of the stressors expected to occur in a region may be
eliminated.
As an example, the discriminatory power of macroinvertebrate metrics
was evaluated for Honda streams. The judgment criteria for discrimina-
tion were based on the degree of interquartile overlap between the least
impaired site category and the impaired site category for each metric A
metric was judged excellent if no overlap existed in the interquartile range
(Fig. 6-5a); poor if the overlap was considerable, and no distinction be-
tween the impairment categories could be made (Fig. 6-5b). An analysis of
a metric's performance among all of the site classes indicated the metric's
strength in discriminating between "good" and "bad" conditions.
Additional research is needed to demonstrate the responses of metrics
to different stressors in different ecoregions or stream systems. However,
once these factors have been considered and demonstrated, the metrics
can be incorporated into localized biocriteria programs. It is also impor-
tant that the metrics and necessary survey methods be appropriate to the
logistical and budgetary resources of the Investigating agency. Practical
application is the penultimate step in metric development. Continued
evaluation of metrics and indices is an essential feature of the use of
biocritena. ,
Biocriteria Based on a MuHtimetric Approach
The validity of an integrated assessment using multiple metrics is sup-
ported by the use of metrics firmly rooted in sound ecological principles
(Fausch et al. 1990; Karr et al. 1986; Lyons, 1992). For biocriteria, a biologi-
cal attribute or metric is some feature or characteristic of the biotic assem-
blage that changes in a predictable way with increased human influence.
It is also important
that the metrics and
necessary survey
methods be
appropriate to the
logistical and .
budgetary resources
of the investigating
agency.
-------
BIOLOGICAL
Technical Guidance for Streams and Small Rivers
20
SS75A
Rctarano* O«w knpHrad
73BCO
i^ Min-Max .
CD 25%-75%
o Median value
Figure «a.—SHe discrimination for the number of Ephomeroptera, Plecoptera, and
Trlchoptera (EPT Incta) In Florida atreama. (Referanet • leaat Impaired, ether •
unknown; Impaired • determined Impaired a priori.)
•8
*
28
24
20
16
12
8
Rttannoa
OS75A
7SBCO
_L_ Min-Max
CZD 25%-75%
° Median value
Rgure 6-5b.—Site discrimination for the number of Chlronomidae taxa In Florida
etreama. (Reference » leaat Impaired, oUwr « unknown, Impaired » determined
Impaired a priori.)
The status of the biota as indicated by a composite of appropriate attri-
butes (metrics) provides an accurate reflection of the biological condition
at a study site. A large number of attributes have been used (e.g., see
Fausch et al. 1990; Karr, 1991; Karr et aL 1986; Kay, 1990; Noss, 1990), and,
each is essentially a hypothesis about the relationship between in-stream
condition and human influence (Fausch et al. 1990). Gray (1989) states that
the three best-documented responses to environmental stressors are reduc-
tion in species richness, change in species composition to dominance by
opportunistic species, and reduction in mean size of organisms. But
-------
Multimetric Approaches for Biocriteria Development
Figure 6-6.—Tl«r*d metric development procees (edcptod from Holland, 1990).
because each feature responds to different stressors, the best approach to
assessment is the incorporation of many attributes into the assessment
process.
The development of appropriate metrics is dependent on the taxa to be
sampled, the biological characteristics at reference conditions, and to a cer-
tain extent, the anthropogenic influences being assessed. They must be
pertinent to the management objectives to which the biocriteria will be ap-
plied. In many situations, multiple stressors impact ecological resources,
and specific "cause and effect" assessment may be difficult. However,
change over sets of metrics in response to perturbation by certain stressors
(or sets thereof) may be used as response signatures.
A broad approach for program-directed development of metrics may be
modeled after Harbour et al. (1992), Fausch et al (1990), Holland (1990), or
Karr and Kerans (1992). Candidate metrics are selected based on knowl-
edge of aquatic systems, flora and fauna, literature reviews, and historical
data (Fig. 6-6). During the research process, these metrics are evaluated for
efficacy and validity. Only after careful evaluation should the metrics be in-
troduced into the biocriteria program. Less robust metrics or those not well-
founded in ecological principles are weeded out in this research process.
Metrics with little or ho relationship to stressors are rejected. The remain-
ing, or core, metrics are those that provide useful information in differenti-
ating among sites having good and poor quality biotic characteristics.
The use of multiple metrics to develop a framework for biocriteria is a
systematic process involving discrete steps. The process includes site classi-
fication (Chapter 3), conduct of a biosurvey and determination of metrics,
aggregation into indices, and the formulation of biocriteria. The conceptual
model for processing biological data into a biooiteria framework is adapted
from Paulsen et al. (1991) and illustrated in Figure 6-7. A description of the
process is summarized in Table 6-1 and described as follows:
• Step 1 — Classification. Sites are classified as described in Chapter 3 to
determine the stream class designation and to ascertain the best and most
representative sites for each stream class. The reference condition will be
7"he development of
appropriate metrics is
dependent on the
taxa to be sampled,
the biological
characteristics at .
reference conditions,
and to a certain
extent, the
anthropogenic
influences being
assessed.
-------
Te&hnical Guidance for Streams and Small Rivers
1. Classification
2. Survey of Biota and Habitat
3. Candidate Metric Evaluation
4. Core Metric Calibration
5. Index Development
6. Biocriteria Development
Indicators
Figure 6-7.—The conceptual process tar proceeding from measurements to Indica-
tors to assessment condition (modified from Pauhwn it si. 1991).
established from this step. Site classification is necessary to reduce and
partition variability in the biological data. Multistate collaboration is en-
couraged in the development of these calibration regions; a benefit is that
common methods and metrics can be established among states and cross-
state comparisons are enhanced.
• Step 2—Biosurvey. Surveys of the best sites and those known to be im-
paired are made for both biota and physical habitat to 'determine the dis-
criminatory power of the metrics using the impaired and best sites within
the stream class. The use of standardized methods (Chapter 4) provides a
better interpretation of the raw data than does a conglomeration of tech-
niques. The raw data from a collection of measurements must be evalu-
ated within the ecological context that defines what is expected for similar
waterbodies (by reference to waterbody type and size, season, geographic
location, and other elements).
• Step 3 — Candidate Metrics Evaluation and Calibration. Analysis of
the biological data emphasizes the evaluation of biological attributes that
represent the elements and processes of the community. All potential met-
rics having ecological relevance are identified in this step.
-------
. , - CHAPTcri 6.
Multimetric Approaches for Biocriteria Development
Table 6-1.—Sequential progression of the blocrittda process.
•KXRrTERIA PROCESS
Step 1. Classification to Determine Reference Conditions and Regional Ecological
Expectations
• stream class designation
• beet and representative sites (reference sites representative of class categories
and natural background physical integrity) ,
Step 2. Survey Best Sites (reference sites) . *
• biota and physical habitat
• database consists of raw data (taxonomic lists, abundance levels, and other
direct measures and observations)
Step 3. Candidate Metric Evaluation
• data analysis (data summaries) of biological attributes
• calculation of candidate metrics
Step 4. Core Metric Calibration
• testing and validation of metrics by stream class
• calibration of metrics to discriminate Impairment
Step 5. Index Development
• determination of biological endpoints
• aggregation of metrics
Step 6. Biocriteria Development
• adjustment by physiochemical covariates
• adjustment by designated aquatic life use
• Step 4 — Core Metric Calibration. From the data analysis, metrics are
evaluated for relevance to the biological community and validated by
stream classes. Calibration of the metrics must address the ability to differ-
entiate between impaired and nonimpaired sites. • •
• Step 5 — Index Development For aggregation purposes, transforma-
tion to scores from values of various scales of measurement relevant to in-
dividual metrics must be done. These scores are normally incorporated
into an index, such as the IBI, which, in turn, becomes part of the final as-
sessment process. The individual metrics may also be used as indicators of
biological condition in the overall assessment of those endpoints — to sup-
port the aggregated index or as individual endpoints.
• Step 6 — Biocriteria Development Biocriteria are formulated from the
indices (Chapter 7) for the stream cleisses and adjusted by physical and
chemical covariates and designated aquatic life uses. The biocriteria may
be based on a single aggregated index or established for several biological
endpoints. -
Potential Metrics for Fish and
Macroinvertebrates
A number of metrics have been developed and subsequently tested in field
surveys of benthic macroinvertebrate and fish assemblages (Karr, 1991).
Because metrics have been recommended for fish assemblages (Karr, 1981;
Karr et al. 1986) and for benthic maoroinvertebrates (Barbour et al. 1992;
-------
BIOLOGICAL CRITERIA:
Technical Guidance for Streams and Small Rivers
A number of
attributes can be
characterized by
metrics within five
general classes:
community structure,
taxa richness, variety,
dominance, and
relative abundance.
Kerans et al. 1992; Ohio Environ. Prot. Agency, 1987; Plafkin et al. 1989),
they will not be reviewed extensively here. A list of the fish assemblage
metrics used in the Index of Biotic Integrity (IBI) is presented in Table 6-2,
which represents variations in regional fauna. Karr (1991) separates these
metrics into three classes: (1) species richness and composition, (2) trophic
composition, and (3) abundance and condition. These classes of character-
istics generally agree with the areas of assemblage response described as
being technically supported (Gray, 1989): reduction in species richness,
shift to numerical dominance by a small number of opportunistic species/
and reduction in the mean body size of individuals.
Benthic metrics have undergone similar evolutionary developments
and are documented in the Invertebrate Community Index (ICI) (Ohio En-
viron. Prot. Agency, 1987), Rapid Bioassessment Protocols (RBPs) (Barbour
et al. 1992; Hayslip, 1992; Plafkin et aL 1989; Shackleford, 1988) and the
benthic IBI (Kerans and Karr, in press). Metrics used in these indices are
surrogate measures of elements and processes of the macroinvertebrate as-
semblage. Although several of these indices are regionally developed,
some are more broadly based; and individual metrics may be appropriate
in various regions of the country (Table 6-3).
Figure 2-2 (see chapter 2) illustrates a conceptual structure for attri-
butes of a biotic assemblage in an integrated assessment that reflects over-
all biological condition. A number of these attributes can be characterized
by metrics within five general classes: community structure, taxa richness,
variety, dominance, and relative abundance. Community structure can be
measured by variety and distribution of individuals among taxa. Taxa
richness, or the number of distinct taxa, reflects the diversity within a sam-
ple of an assemblage. Multimetric uses of taxa richness as a key metric in-
clude the Invertebrate Community Index (Ohio Environ. Prot. Agency,
1987), the Fish Index of Biotic Integrity (Karr et al. 1986), the Benthic Index
of Biotic Integrity (Kerans and Karr, in press), and Rapid Bioassessment
Protocols (Plafkin et al. 1989). Taxonomic richness is also recommended as
critical- information in assays of natural phytoplankton assemblages
(Schelske, 1984). Taxa richness is usually species level but can also be eval-
uated as designated groupings of taxa, often as higher taxonomic groups
(e.g., family and order, among others) in assessments of invertebrate as-
semblages.
Relative abundance of taxa refers to the number of individuals of one
taxon as compared to that of the whole community. Abundance estimates
are surrogate measures of standing crop and density that can relate to both
contaminant and enrichment problems. Dominance (e.g., "measured as
percent composition of dominant taxon"' [Barbour et al. 1992]) or domi-
nants-in-common (Shackleford, 1988) is an indicator of community bal-
ance or lack thereof. Dominance roughly equates to redundancy and is an
important indicator when the most significant taxa are eliminated from the
assemblage or if the food source is altered, thus allowing a few species
that are characterized as opportunists to become substantially more abun-
dant than the rest of the assemblage. As a general rule, dominance of one
or a few species increasing at a site indicates that the influence of human
activities has increased. Comparison to reference conditions provides an
important tool to evaluate the extent to which dominance may reflect
human activities.
-------
101 oiociutma
6-2.—fndtx of Btotte Integrity metrics used in various regions of North America.
ALTERNATIVE
IBI METRICS
1. Total number of species
# native fish species
# salmonid age classes*
2. Number of darter species
# sculpin spades
f benthidnsactivore species
* darter and sculpin species
# saimonid yearings (Individuals)'
% round-bodied suckers
# sculpins (Individuals)
3. Number of sunfish species
# cyprinid species
# water column species
# sunfish and trout species
f salmonid species
# headwater species
4. Number of sucker species
* adult trout species'
# minnow species
if sucker and catfish species
5. Number of intolerant species
# sensitive species
# amphibian species
Presence of brook trout
6. Percent green sunfish
% common carp
% white sucksr
% tolerant species
% creek chub
% dace species
7. Percent omnh/ores
% yearling salmonids*
8. Percent insectivorous cyprinids
% insectivores
% specialized insectivores
# juvenile trout
% insectivorous species
9. Percent top carnivores
% catchable salmonids
% catchable trout
% pioneering species
Density catchable trout
10. Number of individuals
Density of individuals
11. Percent hybrids
% introduced species
% simple lithophilis
# simple lithophilis species
% native species
% native wild individuals
12. Percent diseased individuals
I
X
X
X
X
X
X
•_x.
X
x
X
X
X
X
x
X
X
X
X
X
X
X
X
X
, a
£1
at IB
X
X
X
X
X
X
X
X
X
X
X
X
X
1
X
X
X
X
X
X
X
X
X
1
X
X
X
X
X
X
X
l!
X
X
X
X
X
X
X
X
X
x
- x
X
if
X
X
X
X
x
x
X
X
X
X
X
X
X
X
X
if
ii
X
X
x
X
X
X
X
X
x
X
X
X
X
at
X
X
X
X
X
X
X
X
X*
1
X
x
•Metric suggested by Moyle or Hughes as a provisional replacement metric in small western salmonid streams.
X « metric used in region. Many of these variables are applicable crisewhere.
•Excluding individuals of tolerant species. -
Taken from Kan- et al. (1986), Hughes and Gammon (1987), Miller et al. (1988), Ohio EPA (1987), Steedham (1988), Lyons (1992).
-------
3,CLOGiCAL CRITERIA:
Technical Guidance for Streams and Small Rivers
\
1
Table 6-3. — Examples of metric suites used for analysis
semblages.
ALTERNATIVE
SENTHIC
METRICS tBf RBP»
1. Total number taxa X X
% change in total taxa richness
2. Number EPT taxa X X
# mayfly taxa X
tfcaddisflytaxa • , X
# stonefly taxa
• Missing taxa (EPT)
3. Number dJptera taxa X
# chironomidae taxa
4. Number intolerant snail and mussel species
5. Ratio EPT/chirenomidae abundance
Indicator assemblage Index
SEPT taxa
% mayfly composition ' X
% caddisfly composition X
of macrolnvertebrate aa-
RBP-
RBP8 » OR WA WBI*
X X X XX
XXX
XX X
X
X
X
X
X X '
X
XXX
XXX
X
6. Percent Tribe Tanytarsini X
7. Percent other diptera and noninsect X
composition
8. Percent tolerant organisms X
% corbicula composition
% oligochaete composition
Ratio hydropsychidae/trtooptera X
9. Percent individual dominant taxa X
% individual two dominant taxa
Five dominant taxa in common X
Common taxa index
10. Indicator groups • •
11. Percent individual omnivoree and scavengers
12. Percent individual collector gatherers and flHeren
% Individual fitterers .
13. Percent individual grazers and scrapers
Ratio scrapers/filterer collectors
Ratio scrapers/(scrapers + filterer collectors) X
14. Percent individual strict predators
15. Ratio shredders/total ind. (+ % shredders) X
T6. Percent similarity functional feeding groups (QSI) X
17. Total abundance
18. Pinkham-Pearson Community Similarity Index X
Community Loss Index
Jaccard Similarity Index
. 19. Quantitative Similarity Index (taxa) X
20. Hilsenhoff Biotic Index X
Chandler Biotic Index
21. Shannon-Weiner Diversity Index
Equitability
Index of Community Integrity
' . X
X
x —
XXX
X
X X
X X
X X
X
X
X X
X . X
XXX
X
X X
X
X X
XX
X
X
XXX
X
X
X
X
•Onto EPA (1987)
"Barbour et al. (1992) revised from Plafkin et al. (1989)
cShackelford (1988)
"Hayslip (1 992): ID « Idaho. OR « Oregon. WA « Washington (Note: These metrics In ip, OR. and WA
are currently under evaluation.) . • .
*Kerans and Karr (in press)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^g^^^gjM^^^^^MH^^H^^^^^MM^H^H^MMHHMI^^^H^HH^HMM
-------
. .
Multimetric Approaches for Biocriteria Development
Taxonomic composition can be characterized by several classes of in-
formation, including identity and sensitivity. Identity is the knowledge of
individual taxa and associated ecological principles and environmental re-
quirements. Key taxa (Le., those that zire of special interest or ecologically
important) provide information important to the identity of the targeted
assemblages. The presence of exotics or nuisance species may be an impor-
tant aspect of biotic interactions that relates to both identity and sensitiv-
ity. Sensitivity refers to the numbers of pollutant tolerant and intolerant
species in the sample. The IGI and RBPs use a metric based on species tol-
erance values. A similar metric for fish assemblages is included in the IBI
(Table 6-2). Recognition of rare, endangered, or important taxa provides
additional legal support for remediation activities or recommendations.
Species status for response guilds of bird assemblages — for example,
whether they are threatened or endangered, their endemidty, or some
commercial or recreational value — also relates to the composition class of
metrics (Brooks et al. 1991).
Individual condition metrics characterize assemblage features that re-
sult from sublethal or avoidance response to contaminants. These metrics
focus on low-level chronic exposure to chemical contamination. The condi-
tion of individuals can be rated by-observation of their physical (anatomi-
cal) or behavioral characteristics. Physical characteristics that can be useful
for assessing habitat contaminations result from microbial or viral infec-
tion, teratogenic or carcinogenic effects arising during development of that
individual, or from a maternal effect. These characteristics are categorized
as diseases, anomalies, or metabolic processes (biomarkers).
The underlying concept of the biomarkers approach in biomoxutoring
is that contaminant effects occur at the lower levels of biological organiza-
tion (Le., at the genetic, cell, and tissue level) before more severe disturb-
ances are manifested at the population or ecosystem level (Adams et al
1990). Biomarkers may provide a valuable complement to ecological met-
rics if they are, pollutant specific and if the time and financial costs can be
reduced. Unusual behaviors regarding.motion, reproduction, or eating
habits are often an indication of physiological or biochemical stress. Often
behavior measures are difficult to assess in the field.
A metric of individual condition is used for fish in the IBI as "percent
diseased individuals" (Table 6-2). The potential for development of
biomarkers in biological monitoring exists. McCarthy (1990) briefly dis-
cussed several studies that have shown biomarker responses to correlate
with predicted levels of contamination and site rankings based on commu-
nity level measures of ecosystem integrity.
Assemblage processes can be divided into several categories as poten-
tial metrics. Trophic dynamics encompasses functional feeding groups,
and relates to the energy source for the system., the identity of the herbi-
vores and carnivores, the presence of .detritivores in the system, and the
relative representation of the functional groups. Inferences on biological
condition can often be drawn from a knowledge: of the capacity of the sys-
tem to support the survival and propagation of the top carnivore. This at-
tribute can be a surrogate measure for predation rate. Without relatively
stable food dynamics, populations of the top carnivore reflect stressed con-
ditions. Likewise, if production of a site is considered high based on or-
ganism abundance or biomass, and high production is natural for the
-------
BIOLOGICAL CRITERIA.
Technical Guidance for Streams and Small Rivers
'habitat type under study (as per reference conditions), biological condition
would be considered good.
Process metrics have been developed for a number of different assem-
blages. For example, Table 6-2 indicates at least seven IBI metrics dealing
with trophic status or feeding behavior in fish, focusing on insectivores,
omnivores, or herbivores. Also, number or density of individuate of fish in
a sample (or an estimate of standing crop) may be considered a measure of
production and, thus, in the process class of metrics. Additional informa-
tion is gained from density measures when considered relative to size or
age distribution. Three RBP metrics for benthic macroinvertebrates focus
on functional feeding groups (Table 6-3; Harbour |