v>EPA
United States
Environmental Protection
Agency
Environmental Monitoring
and Support Laboratory
P.O. Box 15027
Las Vegas NV 89114
EPA-600/4-78-040
July 1978
Research and Development
Environmental
Monitoring Series
Macroinvertebrate
Sampling Techniques
for Streams in
Semi-Arid Regions
Comparison of the Surber
Method and a Unit-Effort
Traveling Kick Method
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad categories
were established to facilitate further development and application of environmental
technology. Elimination of traditional grouping was consciously planned to foster
technology transfer and a maximum interface in related fields. The nine series are:
1. Environmental Health Effects Research .
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7. Interagency Energy-Environment Research and Development
8. "Special" Reports
9. Miscellaneous Reports
This report has been assigned to the ENVIRONMENTAL MONITORING series.This series
describes research conducted to develop new or improved methods and instrumentation
for the identification and quantification of environmental pollutants at the lowest
conceivably significant concentrations. It also includes studies to determine the ambient
concentrations of pollutants in the environment and/or the variance of pollutants as a
function of time or meteorological factors.
This document is available to the public through the National Technical Information
Service, Springfield, Virginia 22161
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EPA-600/4-78-040
July 1978
MACROINVERTEBRATE SAMPLING TECHNIQUES FOR
STREAMS IN SEMI-ARID REGIONS
Comparison of the Surber method and
a unit-effort traveling kick method
by
C. E. Hornig
Water and Land Quality Branch
Monitoring Operations Division
Environmental Monitoring and Support Laboratory
Las Vegas, Nevada 89114
and
J. E. Pollard
Biology Department
University of Nevada, Las Vegas
Las Vegas, Nevada 89154
ENVIRONMENTAL MONITORING AND SUPPORT LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
LAS VEGAS, NEVADA 89114
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DISCLAIMER
This report has been reviewed by the Environmental Monitoring and
Support Laboratory, U.S. Environmental Protection Agency, and approved for
publication. Mention of trade names or commercial products does not con-
stitute endorsement or recommendation for use.
ii
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FOREWORD
Protection of the environment requires effective regulatory actions which
are based on sound technical and scientific information. This information
must include the quantitative description and linking of pollutant sources,
transport mechanisms, interactions, and resulting effects on man and his
environment. Because of the complexities involved, assessment of specific
pollutants in the environment requires a total systems approach which tran-
scends the media of air, water, and land. The Environmental Monitoring and
Support Laboratory-Las Vegas contributes to the formation and enhancement of
a sound monitoring data base for exposure assessment through programs designed
to:
develop and optimize systems and strategies for monitoring
pollutants and their impact on the environment
demonstrate new monitoring systems and technologies by applying
them to fulfill special monitoring needs of the Agency's
operating programs
This report assesses the utility of two stream benthic macroinvertebrate
collection methods for the purposes of water quality monitoring. Results
presented herein can be used as a basis for developing water quality monitoring
programs for streams of semi-arid western regions. Potential users of the
information presented Include federal, state, and local environmental and
health agencies, as well as private organizations engaged in water quality
monitoring and assessment. Further information is available from the Water.
and Land Quality Branch, Monitoring Operations Division.
Georg/B/ Morg
Director
Environmental Monitoring and Support Laboratory
Las Vegas, Nevada 89114
iii
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ABSTRACT
Streams of the arid and semi-arid regions of the western United States
are characterized by irregular flow patterns resulting in highly unstable
macroinvertebrate habitats and a sparse macrobenthic fauna. The use of a
standard square-foot Surber stream-bottom sampler is of limited utility in
these regions due to the combined effects of faunal paucity and patchiness.
The efficiency of a unit-effort traveling kick method was compared with that
of a standard Surber sampler in uniform fauna-poor riffles on the White
River, Utah. Comparisons of 50 kick samples with 40 Surber samples revealed
that kick samples provided more highly reproducible data than Surber samples
in terms of counts of individuals and taxa, percentages of composition, and
diversity indices (H). Visual preselection of the richest sites, however,
improved the reliability of Surber sampler data. Some differences in organism
selectivity of the two sampling methods were noted. The Surber method attri-
buted greater relative importance to the more closely adherent and cryptic
forms such as the simuliids, and the kick method was relatively biased towards
easily dislodged organisms such as the baetid mayflies.
iv
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CONTENTS
Foreword *•**
Figures and Tables vi
1. Introduction • 1
2. Conclusions and Recommendations 3
3. Materials and Methods 4
Study Area . . • 4
Sampling Methods 4
Sampling Design 6
Sample Handling and Analysis 9
4. Comparison of Sampling Methods H
Total Counts H
Counts per Taxa . 13
Relative Abundances 13
Richness of Taxa 14
Diversity 15
5. General Discussion I7
References
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FIGURES
Number Page
1 Location of the White River Southam Canyon study area
near the Ua-Ub oil shale tracts in Utah 5
2 Location of sampling stations at the Southam Canyon
study area, White River, Utah 7
TABLES
1 Means (X) and 95% confidence intervals for current and
depth measurements associated with macrobenthic
samples 8
2 Means (X) and coefficients of variation (CV) in percent
for total number of individuals, number of taxa,
and diversity index for each sample set 12
3 Estimated number of samples required for each sampling
method to provide means of total counts within 20%
and 50% of the population mean at the 95% level of
confidence 12
4 Means (X) and coefficients of variation (CV) in percent
for counts of organisms of the nine most common taxa. ... 13
5 Means (X) and coefficients of variation (CV) in percent
for the percentage composition of the nine most common
taxa 14
6 Number of organisms per sample, total number of taxa,
and diversity for each sample set 16
vi
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SECTION 1
INTRODUCTION
Biological monitoring has long been recognized as an effective tool for
evaluating the stability and environmental quality of ecosystems. Biological
investigations are of particular significance in water quality monitoring
programs since they offer a rapid and efficient means for evaluating the
nature and extent of pollution related disturbances.
Biological monitoring should be an integral part of surface water quality
monitoring programs. It should not, however, be viewed as an alternative to
physical-chemical monitoring, but as a complementary tool for improving the
efficacy and broadening the scope of water quality monitoring programs.
Verification of cost-effective biological monitoring procedures is particularly
important for the regions of the western United States which are rich in
energy resources. These areas are expected to undergo considerable development
in the near future, and many hundreds of miles of streams will require baseline
and follow-up faunal surveys if biological monitoring is to be incorporated
into comprehensive monitoring programs.
The relatively stationary bottom-dwelling macroinvertebrate communities
are especially useful as natural monitors of water quality since they respond
in a measurable and predictable manner to most types of pollutants. The
recent history of water quality events can be detected through periodic
sampling of the macrobenthos as the communitie& affected by the disturbance
take weeks or months to recover. Periodic chemical sampling alone may "miss"
short-term water quality fluctuations. In a sense, macrobenthic analysis
provides a mechanism for integration of conditions between sampling periods.
Two attributes of macroinvertebrate communities which are particularly
relevant to water quality investigations are faunal composition (distribution
of the organisms among the species) and density. Accurate estimates of ab-
solute values of these attributes require thorough and time-consuming eco-
logical studies (Hynes 1970). However, estimates of these attributes taken
from a standardized collection, although they may not accurately describe the
entire benthic community, can be reliably compared with estimates of similar
collections. Such comparative studies are relatively easy to conduct and are
very effective for biological monitoring purposes because they can be used to
detect and evaluate spatial and temporal changes in water quality.
Faunal composition of two or more collections can be reliably compared,
provided the same sampling method is employed and the sample size is sufficient.
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Methods of determining how sample size relates to the accuracy of faunal
composition estimates are discussed in terms of species diversity by Pielou
(1966), Wilhm (1970), Hurtubia (1973), and Fraser (1976) and in terms of
number of taxa by Gaufln et al. (1956) and Stout and Vandermeer (1975).
The highly patchy or contagious distribution of macroinvertebrates
necessitates that either very large numbers of replicates (>50) be collected in
order to obtain precise standing-crop estimates (e.g., a 5 to 10 percent
error of the mean), or rougher estimates (e.g., a 20 to 100 percent error of
the mean) involving much fewer numbers of samples (<10) will have to be the
object (Chutter 1972). However, natural variation in density is often so high
that precise estimates have little meaning for purposes of water quality
monitoring. In these cases, only when abundances change considerably can a
man-made disturbance be suspected. This is particularly true in streams
subject to intermittent flooding, where a single spate could reduce the
density of organisms dramatically (Hynes 1970). Even through standing-crop
estimates are relatively imprecise, they are valuable, as large changes in
macroinvertebrate density will be detected.
Most stream macrobenthic samplers, such as the Surber (square-foot)
sampler, are primarily designed for estimating standing crop. They are
standardized by unit area and collect from relatively small areas of stream
bottom. However, for purposes of estimating faunal composition, very large
numbers of small-area replicates are often required to obtain reproducible
data. This sampling problem is especially critical for streams of the semi-
arid western regions where the bottom organisms may be relatively sparse due
to the effects of intermittent spates accompanied by large sediment loads.
There is a need to standardize and validate a sampling method for these
streams which provides greater areal coverage with minimum effort and which
provides more precise estimates of faunal composition than is generally
achieved with area-standardized samplers such as the Surber sampler.
This report compares a standardized, unit-effort traveling kick method
with the Surber method for obtaining macroinvertebrate data from fauna-poor
areas of western United States streams characterized by episodic flow patterns.
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SECTION 2
CONCLUSIONS AND RECOMMENDATIONS
Intensive macroinvertebrate sampling from a fauna-poor riffle area on the
White River, Utah, utilizing two standardized techniques, demonstrated that
the unit-effort traveling kick method was more efficient and cost-effective
than the Surber sampling method for the purposes of biological monitoring.
Replicate variability for the unit-effort traveling kick method was consid-
erably lower than that for the Surber sampling method for kinds of taxa
collected, percentage data of the more common taxa, and diversity index
values. Under test conditions fewer kick net than Surber net samples were
therefore required to obtain reproducible estimates of faunal composition.
For purposes of detecting relative changes in the macrobenthic density, the
kick net also provided reliable count data more efficiently (fewer replicates
required) than did the Surber sampler. This increased efficiency is estimated
to save as much as 75% sample collecting and sorting time to achieve a 50%
level of precision for abundance estimates.
The unit-effort traveling kick method is much more versatile than the
Surber sampling method. It can be used in riffles with water depths up to 1
meter, whereas the Surber sampler is of limited utility In waters over 30 cm
deep. The increased efficiency and versatility of the kick method overcomes
many of the sampling limitations associated with site suitability (particu-
larly during periods of high discharge) and minimizes the numbers of replicate
samples required. If Surber samples are to be collected from fauna-poor
streams, the sample site selection should be limited to the fauna-rich areas
of the riffle. Such site selection provides relatively large numbers of or-
ganisms per sample and low variability, thereby increasing water quality
monitoring utility.
Although the present study only compares sampler performance in one
riffle of one river, we are recommending intensive testing of the unit-effort
traveling kick method for routine biological monitoring in larger fauna-poor
western streams. A long fine-meshed (12 to 16 strands per cm) net is recom-
mended for use with this method. In addition, selection of riffle habitats
composed of medium-sized (approx. 10 cm) loose rocks with little or no vege-
tation and depths between 15 and 60 cm is recommended for the most effective
employment of the unit-effort traveling kick method.
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SECTION 3
MATERIALS AND METHODS
STUDY AREA
The White River in Colorado and Utah (Figure 1) is representative of many
rivers in the Colorado River Basin. Water quality in the upper reaches is
excellent, supporting good trout populations and a rich, diversified inverte-
brate fauna. The river becomes increasingly turbid, progressing downstream,
with chemical water quality undergoing a dramatic change characterized by an
increase in dissolved solids. The downstream reaches of the river support a
rather meager warm-water fishery and an unstable invertebrate fauna.
The study area was located at Southam Canyon, White River, Utah, near the
Ua-Ub federally leased oil shale tracts (Figure 1). The mean annual discharge
at Southam Canyon is 20 cubic meters per second and the stream's width is
about 30 meters during periods of normal flow. The stream at the study area
was bisected by a large stable island. Riffles with various water depths were
located on both sides of the island. This was the only extensive riffle area
within the mile stretch at Southam Canyon accessible by road. The substrate
of the riffles was quite uniform and consisted of easily dislodged, flat shale
stones (ranging in diameter from 5 to 20 cm) interspersed with fine and coarse
gravel and underlain with gravel and sand. Except for a thin layer of peri-
phyton (mainly diatoms), the substrate was quite free of attached vegetation,
although it contained a considerable amount of trapped debris.
During the study period, September 5-6, 1976, the stream flow was rela-
tively low and the water exceptionally clear in the lower White River due to
the lack of any recent rains in the watershed.
SAMPLING METHODS
Surber Method
A standard 0.093-m2 (1 square foot) Surber sampler was modified as
follows. The original net (68 cm long with 10 strands per cm), supplied by
Wildco Supply Co., was replaced by a 90-cm-long, conical-shaped, 12-strand-per-
cm (30 mesh) nylon net. It was assumed that the longer net would reduce
backwash from the sampler, while the finer-meshed netting would allow entrap-
ment of the smallest organisms defined as macroinvertebrates, i.e., those
invertebrates retained by 30-mesh netting (U.S. EPA 1973). Surber samples
were collected in accordance with prescribed methods (Needham and Needham
1962).
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: TO
;BONANZA
UTAH
WHITE RIVER
COLORADO
1 2 km
Figure 1. Location of the White River Southam Canyon study area near the Ua-Ub oil shale tracts
in Utah.
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Unit-Effort Traveling Kick Method
Unit-effort traveling kick samples were collected using a modified
Turtox triangular dip net with a mouth opening of 28 cm by 28 cm by 34 cm.
The 22-cm-long, 9-strand-per-cm net supplied with the sampler was replaced
with a pyramid-shaped 76-cm long nylon net with 16 strands per cm (40 mesh).
Kick samples were collected by holding the net in front of and downstream
from the investigator while traveling slowly downstream and vigorously kicking
the substrate. All kick sampling was standardized by holding the net in the
water for 30 seconds. An area approximately 3/4 by 4 meters (3 m ) was dis-
turbed for each sample.
SAMPLING DESIGN
Five distinct sets of samples were collected from the four stations at
the Southam Canyon study area (Figure 2). The 40-cm water depth of the
riffle on the south side of the larger island was too deep for practical
application of the Surber method. This location was designated Station 1 and
a 40-replicate set of 30-second traveling kick samples was collected here.
Stations 2, 3, and 4 (Figure 2) were located in the riffles on the
northwest side of the larger island and around the smaller island. Water
depths at these stations were well under 30 cm, and the substrate conditions
were very similar at all stations. The site selection for the individual
Surber samples differed at each station. Three methods of Surber sample site
selection were used: (a) Station 2 - selection of sites by current speed (20
samples); (b) Station 3 - random selection of sites (10 samples); and (c)
Station 4 - selection of rich sites (10 samples). Also, a set of ten 30-
second traveling kick samples was collected from Station 2. The individual
kick sample sites were selected in a systematic manner, beginning at the
downstream end of the station, and taking care not to overlap sampling sites.
Since the traveling kick method covered a large area of bottom and many
habitat conditions, it did not seem necessary to select individual sites in
the manners used for Surber site selection.
Each replicate of a kick or Surber set was collected alongside or up-
stream from the preceding replicate so that material stirred up by the sampling
activity did not disturb organisms at sites yet to be sampled. Current-speed
and water-depth measurements were taken at each Surber sample site (including
occasional replicate readings) and were taken at alternate kick replicate
sites (Table 1).
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KEY
STATION NUMBER AND TYPi OF SAMPLES
40 THIRTY-SECOND TRAVELING KICK SAMPLES
10 THIRTY-SECOND TRAVELING KICK SAMPLES
20 RANDOMIZED CURRENT SELECTED SURBERS
10 RANDOMLY SELECTED SURBERS
10 RICH AREA SELECTED SURBERS
SCALE
20 METERS
Figure 2. Location of sampling stations at the Southam Canyon study area, White River, Utah.
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TABLE 1. MEANS (X) AND 95% CONFIDENCE INTERVALS FOR CURRENT AND DEPTH
MEASUREMENTS ASSOCIATED WITH MACROBENTHIC SAMPLES
Station
Type of
Sample
Current speed (cm/s)
Depth (cm)
Number of
Measure-
ments X
95%
Confidence
Intervals
Number of
Measure-
ments X
95%
Confidence
Intervals
1
2
2
3
4
Kick
Kick
Surber
Surber
Surber
19
6
24
12
12
41.5
67.8
68.1
49.3
47.0
±1.6
±6.8
±1.1
±3.6
±3.7
14
6
20
10
10
40.0
17.0
12.1
9.3
8.0
±2.5
±5.0
±0.8
±0.8
±0.6
Selection of Sites by Current Speed
The rate of stream flow will vary from place to place over a shallow
riffle due to the influence on the flow caused by bottom rocks of various
sizes. In turn, current velocity affects the distribution of many benthic
species (Hynes 1970). Thus, to attempt to reduce sample variability, a set of
Surber replicates were collected from sites which were affected by the same
narrow range of current speeds.
The general area chosen for the Surber replicates (Station 2) was deter-
mined by the availability of a suitable uniform riffle area. A tape measure
was placed along the stream bank at the riffle, and 20 points along the tape
were selected by the use of a random numbers table. Final determination of
individual sites was accomplished by the investigator placing a Gurley-Teledyne
current meter in the riffle opposite one of the selected points and slowly
moving the meter perpendicular to the tape until a current speed estimated to
be between 60 and 75 centimeters per second was found. The current was then
measured for 60 seconds at a point six-tenths of the distance from surface to
the bottom. If the current was not between 60 and 75 centimeters per second,
the site was rejected and the current meter was again moved along the line
perpendicular to the tape until an appropriate site was located. This procedure
assured that any effects of current on sampling results would be minimized.
All sites were at least 60 cm apart so that sites in close proximity would not
be disturbed by adjacent sampling activities.
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Random Selection of Sites
Randomly selected Surber sampling sites (Station 3) were selected by the
establishment of a 3-meter-by-3-meter grid and the use of a two-digit random
numbers table. If sites were closer than 60 cm to each other, another random
number was chosen from the table.
Selection of Rich Sites
It was assumed that places in a riffle with piled-up rocks would provide
more depth to the substrate and more trapped debris, and hence a larger
surface area available for colonization. Portions of the bottom where rocks
were visibly piled the highest were designated as rich sites (Station 4).
Surber samplers were placed so that the pile of rocks chosen as a rich site
was surrounded by the sampler frame.
SAMPLE HANDLING AND ANALYSIS
Samples were initially transferred from the Surber and kick nets to a
bucket with a 12-strand-per-em (30 mesh) screen on the bottom to avoid any
accidental loss of organisms. Since 40-mesh and 30-mesh nets were used to
collect the kick and Surber samples respectively, use of a 30-mesh screen for
sample washing improved consistency between the methods in terms of minimum
size of organisms included in the data. Samples were placed in mason jars
and preserved with 100% Formalin solution in volumes approximately equivalent
to the amount of organic debris in the sample, resulting in at least a 5%
solution.
In the laboratory samples were washed clean of Formalin by placing them
in a jar covered with a 12-strand-per-cm screen, pouring off the Formalin,
and then rinsing the samples thoroughly with water.
Macroinvertebrates and debris were sorted from the gravel and sand by
placing the sample in a round-bottom container with water, agitating the
sample, and pouring off the debris and organisms. This process was repeated
until no organisms could be found in the gravel and sand remaining in the
container. Macroinvertebrates were then hand sorted from the debris in a
shallow white pan. All macroinvertebrates in the samples were identified to
species, when possible, and enumerated. (Chironomids and simuliids have been
identified only to family; generic determinations are currently underway.)
Dr. Richard Baumann of Brigham Young University, Provo, Utah, has confirmed
the majority of identifications.
Standard statistical techniques were used in analyzing the data. The
coefficient of variation (CV), i.e., the standard deviation divided by the
mean, was calculated and expressed in percent.
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The estimation of sample size required for a given level of precision
was calculated according to the methods given by Steele and Torrie (1960):
n
t2 CV2
P2
where n = estimated number of samples required
t = Student's t value for a given probability
level and degrees of freedom based on the
number of replicates
CV = coefficient of variation
p = acceptable percent error of the sample mean
from the population mean
The average diversity per individual for these samples was estimated
from the Shannon-Wiener formula (Shannon and Weaver 1963) :
S
H = -I P. Iog2 P.
where P = proportion of the 1th taxon in the sample, which
is calculated from n./N
n. = number of Individuals of the ith taxon
N = total number of individuals
S = total number of taxa
The value H will increase with an increase in the number of taxa collected
and/or with an increase in the evenness of the distribution of individuals
among the taxa. Thus, H is a measure which takes into account both the
number of species in a collection and their relative abundances.
10
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SECTION 4
COMPARISON OF SAMPLING METHODS
TOTAL COUNTS
The unit-effort traveling kick method collected higher counts of organisms
per sample and yielded statistically more reproducible data than did the
Surber method as expressed by lower coefficients of variation (Table 2)*. For
example, at Station 2 the Surber method collected 21 organisms per sample,
while the kick method collected more than 11 times as many organisms per
sample (236) and yielded a coefficient of variation only about one-third that
of the Surber method (29% vs. 83%). However, the Surber method collected many
more organisms per unit area of bottom than did the traveling kick method.
Each 30-second traveling kick sample was estimated to cover an approximate
3-m2 area. Therefore, the area sampled is approximately 30 times as large as
that covered by a Surber sample, and the number of organisms collected per
unit bottom area is only 37% of the number collected per area by the Surber
method. However, this lack of thoroughness in sampling by the kick method is
more than compensated for by the 30-fold increase in the area sampled. The
kick method results in a net increase of organisms collected and a net decrease
in replicate variability.
Required sample size was estimated for acceptable percent errors of the
sample mean from the population mean of 20% and 50%. Sampling efficiency as
measured in these terms ranged from 2.5 to 7.5 times higher for the kick
method than for the Surber method (Table 3).
The set of Surber replicates collected from the rich sites of a riffle
(Station 4) yielded the most organisms and produced the least variable data of
the three Surber collections (Table 2). The 48% coefficient of variation
obtained for total counts is consistent with the findings of Hassler and Tebo
(1958) who reported a CV of 50% with Surber samples taken from eastern streams.
In addition, the 29 samples estimated to be required to obtain a mean within
207, of the population mean (Table 3) was comparable to results obtained by
Chutter (1972) for randomized Surber sample data compiled by Needham and
Usinger (1956) from a relatively productive western mountain stream. Chutter
found 28 samples were required to obtain the same precision.
* 'Quantitative1 macroinvertebrate sampling techniques are often con-
sidered by benthic biologists as those which are standardized for unit area
(Elliot 1971). However, this should not imply that data collected in any
other standardized manner cannot be subjected to quantitative presentation,
such as in Table 2.
11
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TABLE 2. MEANS (X) AND COEFFICIENTS OF VARIATION (CV) IN PERCENT FOR TOTAL
NUMBER OF INDIVIDUALS, NUMBER OF TAXA, AND DIVERSITY INDEX FOR
EACH SAMPLE SET
Station
1
2
2
3
4
TABLE 3.
Station
1
2
2
3
4
Type of Number
Sample Samples
Kick 40
Kick 10
Surber 20
Surber 10
Surber 10
Total Number of Diversity
Counts Taxa Index
of
X CV X CV X CV
118 30.6 11 15.4 2.79 7.2
236 29.2 13 19.9 2.61 3.8
21 83.3 ' 6 34.3 2.02 19.8
16 67.5 6 52.5 2.02 44.6
69 48.0 9 20.2 2.47 12.2
ESTIMATED NUMBER OF SAMPLES REQUIRED FOR EACH SAMPLING METHOD TO
PROVIDE MEANS OF TOTAL COUNTS WITHIN 20% AND 50% OF THE POPULATION
MEAN AT THE 95% LEVEL OF CONFIDENCE
Type of
Sample
Kick
Kick
Surber
Surber
Surber
Number of Samples Required to Provide Sample
Mean Values Within:
20% 50%
10 2
11 2
76 12
58 9
29 5
12
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COUNTS PER TAXA
Analysis of count data for each of the nine most abundant taxa (repre-
senting at least 95% of all organisms collected) demonstrated that unit-effort
traveling kick samples provided higher counts per sample and better statistical
reproducibility than Surber samples for most of the common taxa (Table 4).
The mean of the coefficients of variation for counts of individuals for all
nine taxa were only 59% and 56% for the kick sets as compared to 138%, 120%,
and 94% for the Surber sets. The Station 2 kick samples showed lower varia-
tion (CV value) for each of the nine taxa than the directly comparable Station
2 Surber sample set. The Surber samples collected from rich sites (Station 4)
provided better reproducibility than did the other Surber sets.
TABLE 4. MEANS (X) AND COEFFICIENTS OF VARIATION (CV) IN PERCENT FOR COUNTS
OF ORGANISMS OF THE NINE MOST COMMON TAXA. (These taxa represent at
least 95% of all organisms collected for any given set of samples.)
Station: 1
Type of Sample: Kick
Number of Samples: 40
TAXON
Rithrogena undulata
Tvaverella albertana
Daatylobaetis oepheus
Pseudooleon sp.
Tvioorythodes minutus
Isogenoides colubrinue
Chironomidae
Simuliidae
Hexatoma sp.
Mean CV
X
10
7
38
11
2
7
19
14
7
CV
53
51
40
65
80
56
83
49
54
59
2
Kick
2
Surber
10
X
75
42
32
48
2
7
8
15
1
CV
31
34
50
49
101
47
48
53
90
56
X
2
6
1
2
1
1
1
8
1
20
CV
98
89
101
100
113
113
248
134
244
138
3
Surber
X
3
3
1
4
1
1
1
3
1
10
CV
62
89
115
64
170
194
129
98
161
120
4
Surber
X
7
12
1
11
1
1
5
27
1
10
CV
38
40
132
58
60
139
91
61
225
94
RELATIVE ABUNDANCES
Analysis of the percentage composition data for the nine most abundant
taxa again demonstrated that unit-effort traveling kick samples provided
better statistical reproducibility than Surber samples in most cases (Table
5). The mean of the coefficient of variation values for percentage data for
all nine taxa were 31% and 34% for the kick sets, as compared to 112%, 112%,
and 65% for the Surber sets. The kick sample set collected from Station 2
showed lower variation for each of the nine taxa than the directly comparable
Station 2 Surber sample set. However, the Surber sample set collected from
the rich sites at Station 4 provided better reproducibility for five of the
nine common taxa collected from the Station 1 kick sample set and for two of
the nine taxa collected from the Station 2 kick sample set.
13
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TABLE 5. MEANS (X) AND COEFFICIENTS OF VARIATION (CV) IN PERCENT* FOR THE
PERCENTAGE COMPOSITION OF THE NINE MOST COMMON TAXA. (These taxa
represent at least 95% of all organisms collected for any given
set of samples.)
Station: 1
Type of Sample: Kick
Number of Samples: 40
TAXON
Rithrogena undulata
Traverella albertana
Daatylobaetis cepheus
Pseudoaloen sp.
Triaorythodes minutus
Isogenoides oolubvinus
Chironomidae
Simuliidae
Hexatoma sp.
Mean CV
X
9
6
32
9
2
6
15
12
6
CV
36
25
12
32
54
31
36
27
28
31
2
Kick
2
Surber
10
X
32
18
13
20
1
3
4
7
1
CV
11
16
22
16
91
18
25
34
76
34
X
11
32
4
9
3
4
2
29
1
20
CV
75
33
86
69
120
106
208
56
256
112
3
Surber
X
18
21
4
26
2
2
2
20
2
10
CV
59
100
108
37
168
167
130
72
166
112
4
Surber
X
11
19
2
15
2
2
7
38
1
10
CV
23
19
112
16
42
89
46
14
220
65
*The arc-sine transformation (sin~V p , where p is the proportion of
the taxon) was used to normalize percentage data before the CV was calculated.
Some relative differences in the selectivity of the two sampling tech-
niques were evident in the data. For example, the unit-effort traveling kick
method placed greater relative importance on the swimming baetid mayfly,
Daotylobaetis oepheus, while Surber sampling attributed greater relative im-
portance to the more closely adherent Tvavevel'La albevtana and Simuliidae
(Table 5). These differences in the relative representation of the organisms
were primarily because the closely attached forms were more easily missed by
the kick technique. In fact, the underrepresentation of these forms in the
kick net collections was chiefly responsible for the lower total number of
organisms collected per unit area by the kick method. As mentioned previously,
when the counts of the Station 2 kick and Surber sets were corrected for unit
area,^ the total count per area for the kick method was 37% of that for the
Surber sampler. The great majority of this difference in total count (89%)
could be accounted for by the differences in counts of the two common closely
adherent taxa, Simuliidae and Traverella albevtana. The other common forms
collected from Station 2 showed very similar actual counts per area for both
methods.
RICHNESS OF TAXA
Relative performance of the two methods with respect to number of taxa
collected was particularly evident in the data from the directly comparable
14
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kick and Surber sample sets taken at Station 2. The combined total of the 10
kick replicates and the 20 Surber replicates collected from the Station 2
riffle yielded 23 taxa. Nine of these taxa were found only in the set of 10
kick samples, while only a single taxon was found exclusively in the set of 20
Surber samples (Table 6). The difference between the taxa lists for these
sample sets will likely increase when the highly diverse chironomids are
identified. Only eight chironomids were found in the set of 20 Surber samplers
while 81 were found in the set of 10 kick samples. (The 42 chironomids exam-
ined thus far from the Station 2 kick sample set have been tentatively sepa-
rated into 16 different species.)
The unit-effort traveling kick method yielded a greater mean number of
taxa per sample (11 and 13) than the Surber method (6 to 9) (Table 2). It
also provided lower between-replicate variability (15%-20% CV vs. 20%-52% CV)
for the number of taxa collected per sample (Table 2).
The Surber samples collected from rich sites (Station 4) gave the best
results of the Surber sets (Tables 2 and 6). This sample set yielded the
highest number of total taxa (16), the highest average number of taxa per
sample (9), and the least variability for number of taxa (20% CV) of the
Surber sample sets.
DIVERSITY
Diversity indices, in themselves, are often difficult to interpret as
indicators of water quality (Pinkham and Pearson 1976). The Shannon-Wiener
diversity index (H), however, is a good measure of the representativeness of a
particular collection of organisms, taking both species richness and distri-
bution of individuals among the species into account (U.S. EPA 1973). The
variability of diversity indices among replicates can thus be used as an
overall measure of the reproducibility of the collection and, therefore, the
reliability of the sampling methodology employed (Grossman and Cairns 1974).
This fact is independent of the question of the applicability of the index to
water quality determinations.
The mean diversity index values (H) calculated for each unit-effort
traveling kick sample set was statistically more reproducible (4%-7% CV) than
the diversity values for the Surber sample sets (12%-45% CV) (Table 2). The
highest reproducibility for diversity values (12% CV) among the Surber sets
was provided by the sample set collected from the rich sites at Station 4.
15
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TABLE 6. NUMBER OF ORGANISMS PER SAMPLE, TOTAL NUMBER OF
TAXA, AND DIVERSITY FOR EACH SAMPLE SET
TAXON
Station:
Type of Sample:
Number of Samples:
1
Kick
~40~
2
Kick
10
2
Surber
20
3
Surber
10
4
Surber
10
EPHEMEROPTERA
Rithrogena undulata
Heptagenia elegantula
Ephemerella inermie
Traverella albertana
Choroterpee albiannulata
Centroptilum ap.
Baetia ap.
Dactylobaetia oepheue
Paeudocloen ap.
Callibaetie ep.
Tricorythodee app.
Lachlonia eaakatoheuanenaie
PLECOPTERA
laogenoidea oolubrinua
Acroneuria abnomria
ODONATA
Ophiogomphua aeverua
Hetaerina amerioana
TRICHOPTERA
Hydropayahe ap. A
Bydropayohe ap. B
Broohyaentrua ap.
Bydroptila ep.
Agraylea ealteoea'(?)
Heotriahia ep.
DIPTERA
Chironomidae
Simuliidae
Empididae
Hexatcma ap.
Tipula ap.
Atherix voriegata
COLEOPTERA
Miorocylloepue ap.
Stenelmie ap.
ACARI
Sperohon ap.
TOTAL
Mean Numbet of Organisms per Sample
10
38
11
19
14
118
75
1
1
42
1
32
48
8
15
1
1
236
21
16
Number of Taxa per Sample Set
29 22 14 13
7
1
12
1
11
5
27
69
16
Peeled Diversity (H)* per Sample Set
2.98 2.71 2.58 2.86 2.64
*A11 organisms collected in a set of samples were pooled in order to
estimate H.
16
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SECTION 5
GENERAL DISCUSSION
Eggllshaw (1964), Frost et al. (1971), and Grossman and Cairns (1974)
investigated a kick method which disturbed small areas of substrate while the
investigator remained relatively stationary. Data from these studies indi-
cated they were performed in relatively rich habitats where small-area samples
collected substantial numbers of organisms. The average coefficient of
variation (41%) derived from Egglishaw's total count data was similar to that
obtained in the present study using a unit-effort traveling kick method (30%).
In addition, Egglishaw found that data resulting from differences between
investigators' kicking techniques were "not large." Frost et al. (1971)
evaluated the stationary kick method as an alternative to the Surber sampler,
which they described as "cumbersome in rapid streams deeper than 30 cm." They
found that although a large proportion of benthic organisms either bypassed
the kick net or remained attached to the substrate, the reproducibillty between
samples was high enough to allow them to apply statistical tests for comparisons
between sets of samples. Grossman and Cairns (1974) found the reproducibility
of kick samples to be better than or comparable to that of artificial substrate
samples in terms of community diversity. Results of the present study similarly
indicate that unit-effort traveling kick samples provide reliable data for
benthic investigations.
The unit-effort traveling kick method cannot be as precisely standardized
as the more common methods which are standardized in terms of unit area. The
kick method also is less thorough and misses a large proportion of the or-
ganisms living in the area being sampled. However, these disadvantages are
outweighed in fauna-poor areas by the advantages of sampling an area approx-
imately 30 times larger per replicate with no more time or effort expended.
The larger the area sampled the more information (organisms) the sample con-
tains. In addition, the relatively large sample variability resulting from
the contagious faunal distribution found in stream benthos is minimized when
a greater area is sampled.
The unit-effort traveling kick method yielded less variable data between
replicates than the more conventional Surber sampler method for all parameters
investigated, indicating that fewer replicates are required to provide a basis
for comparative studies. For example, 12 Surber replicates, as opposed to 2
kick replicates, were required from Station 2 to reach a 50% level of precision
for total count data (Table 3). Sample collection and handling takes approx-
imately 15 minutes per kick or 30 minutes per Surber replicate. An additional
5-1/2 hours of field effort, then, were required to reach a 50% level of
precision when the Surber method was employed rather than the kick method. In
addition, the sorting and counting of organisms is a very time-consuming
17
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procedure. In processing the Southam Canyon samples, it took approximately 8
hours to sort and count 2 kick replicates, while about 24 hours were required
to sort and count 12 Surber replicates. All together, a minimum of 21-1/2
additional hours of effort (30 hours vs. 8-1/2 hours) were required to obtain
even roughly reproducible total count data from a single fauna-poor station
with Surber sampling. The difference in time expenditure would be even greater
if a higher level of precision is required.
The unit-effort traveling kick method also showed lower replicate vari-
ability than the Surber method for the community composition parameters of
richness of taxa, relative abundance, and community diversity. These results
are particularly relevant to water quality determinations. A major objective
of such studies is to make comparisons of the faunal composition (kinds of
organisms and their relative abundances) of collections taken at different
locations and times.
Ease of operation and flexibility of a sampling method should also be
taken into account. The proper use of the Surber method requires manipulation
by hand of substrate materials enclosed by the sampler frame. The required
dexterity is very difficult to achieve in cold waters with either numb fingers
or heavy gloves. (Thin gloves quickly tear against the rocky substrate.) The
kick net is effective in water depths up to 1 meter, as compared to a 30-cm
maximum depth for the practical use of the Surber sampler. This increased
versatility of the kick net provides much additional sampling capability in
areas and during seasons in which Surber sampling is impossible.
It is not surprising that the two methods demonstrated relative differ-
ences in their selectivity for some of the taxa. Hynes (1970) points out that
all sampling methods tend to be selective. However, as stated in the intro-
duction, a primary intent of biological water quality investigations is to
make comparisons over time and space. It is only important, here, that infer-
ences involving changes in the biota come from reproducible collections that
are furnished by the same sampling methodology. If a more complete description
of macroinvertebrate fauna is desired, kick net collections can be supple-
mented with collections and observations of the more securely attached forms
through stone lifting.
In addition to comparing the unit-effort traveling kick method with the
Surber method, this study compares methods of Surber site selection at a
fauna-poor area. Selection of the "richest" sites (Station 4) of a riffle
produced the least variable of the Surber method data for all parameters
investigated. However, sample site selection is often a problem in streams
such as.the lower White River which are frequently too turbid for visual
selection.
The Station 2 set of Surber samples collected from sites selected from a
narrow range of current speed conditions showed little overall improvement in
variability when compared to samples selected in a simple random manner
(Station 3 sample set). However, the current speeds of the Station 3 sites
were also quite similar to each other. Thus, little can be concluded from
these data concerning the influence of current speed variability on sampling
efficiency.
18
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More detailed statistical analyses of these results and analyses of
results from additional study areas (including variation caused by mesh size,
sampling investigator and length of collection time) along with comparisons of
artificial substrate samplers are in progress and will be included in sub-
sequent reports.
19
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REFERENCES
Chutter, R. M. 1972. A reappraisal of Needham and Usinger's data on the
variability of a stream fauna when sampled with a Surber sampler. Limnol.
Oceanogr. 17: 139-141.
Grossman, J. S., and J. Cairns. 1974. A comparative study between two dif-
ferent artificial substrate samplers and regular sampling techniques.
Hydrobiologia 44: 517-522.
Egglishaw, H. J. 1964. The distributional relationship between bottom fauna
and plant detritus in streams. J. Anim. Ecol. 33: 463-476.
Elliot, J. M. 1971. Some methods for the statistical analysis of samples of
benthic invertebrates. Freshwater Biological Association. Scientific
Publication. 25: 1-144.
Fraser, D. F. 1976. Empirical evaluation of the hypothesis of food compe-
tition in salamanders of the genus Plethodon. Ecology 57: 459-471.
Frost, S., A. Huni, and W. E. Kershaw. 1971. Evaluation of a kicking tech-
nique for sampling stream bottom fauna. Can. J. Zool. 49: 167-173.
Gaufin, A. R., E. K. Harris, and H. J. Water. 1956. A statistical evaluation
of stream bottom sampling data obtained from three standard samplers.
Ecology 37: 643-648.
Hassler, W. W., and L. B. Tebo, Jr. 1958. Fish management investigations
on trout streams. Fed. Aid Proj. F4-R Comp. Report. Fish Div., N. C.
Wildl. Resour. Cotnm., Raleigh, N. C.
Hurtubia, J. 1973. Trophic diversity measurement in sympatric predatory
species. Ecology 54: 885-890.
Hynes, H. B. N. 1970. The ecology of running waters. University of Toronto
Press, Toronto. 555 pp.
Needham, J. G., and P. R. Needham. 1962. A guide to the study of freshwater
biology. Holden-Day, Inc., San Francisco. 108 pp.
Needham, P. R., and R. L. Usinger. 1956. Variability in the macrofauna of
a single riffle in Prosser Creek, California, as Indicated by the Surber
sampler. Hilgardia 24: 383-409.
20
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Pielou, E. C. 1966. The measurement of diversity in different types of
biological collections. J. Theor. Biol. 13: 131-144.
Pinkham, C. F., and J. G. Pearson. 1976. Applications of a new coefficient
of similarity of pollution surveys. J. Water Pollut. Contr. Fed.
48: 717-723.
Shannon, C. E., and W. Weaver. 1963. The mathematical theory of communi-
cation. University of Illinois Press, Urbana. 117 pp.
Steele, R. G. 0., and J. H. Torrie. 1960. Principles and procedures of
statistics with special reference to the biological sciences. McGraw-
Hill, New York. 481 pp.
Stout, J., and J. Vandermeer. 1975. Comparison of species richness for
stream-inhabiting insects in tropical and mid-latitude streams. The
Amer. Natur. 109: 263-280.
U.S. Environmental Protection Agency. 1973. Biological field and laboratory
methods for measuring the quality of surface waters and effluents. Environ-
mental Monitoring Series. EPA-670/4-73-001. U.S. Environmental Protection
Agency. Cincinnati, Ohio. 176 pp.
Wilhm, J. L. 1970. Effect of sample size on Shannon's Formula. Southwest.
Natur. 14: 441-445.
21
GOVERNMENT PRINTING OFFICE: 1978 - 786-064/1244 Region No. 9-1
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
REPORT NO.
EPA-600/4-78-040
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
MACROINVERTEBRATE SAMPLING TECHNIQUES FOR STREAMS
IN SEMI-ARID REGIONS: Comparison of the Surber
method and a unit-effort traveling kick method
5. REPORT DATE
July 1978
6. PERFORMING ORGANIZATION CODE
AUTHOR(S)
C. E. Hornig and J. E. Pollard
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Environmental Monitoring and Support Laboratory
U.S. Environmental Protection Agency, and
Biology Department, University of Nevada
Las Vegas, Nevada
10. PROGRAM ELEMENT NO.
1HD620
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
U.S. Environmental Protection Agency-Las Vegasr NV
Office of Research and Development
Environmental Monitoring and Support Laboratory
Las Vegas, Nevada 89114
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
EPA/600/07
15. SUPPLEMENTARY NOTES
16. ABSTRACT
Streams of the arid and semi-arid regions of the western United States are character-
ized by irregular flow patterns resulting in highly unstable macroinvertebrate
habitats and a sparse macrobenthic fauna. The use of a standard square-foot Surber
stream-bottom sampler is of limited utility in these regions due to the combined
effects of faunal paucity and patchiness. The efficiency of a unit-effort traveling
kick method was compared with that of a standard Surber sampler in uniform fauna-poor
riffles on the White River, Utah. Comparisons of 50 kick samples with 40 Surber
samples revealed that kick samples provided more highly reproducible data than Surber
samples in terms of counts of individuals and taxa, percentages of composition, and
diversity indices. Visual preselection of the richest sites, however, improved the
reliability of Surber sampler data. Some differences in organism selectivity of the
two sampling methods were noted. The Surber method attributed greater relative
importance to the more closely adherent and cryptic forms such as the simuliids, and
the kick method was relatively biased towards easily dislodged organisms such as
the baetid mayflies.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c. COS AT I Field/Group
Benthos - Aquatic biology
Limnology •*•• Streams
Sampling - Collecting methods
Samplers - Sampling
Semiriarid regions
Macroinvertebrates
Kick net sampler.
Surber net sampler
White River, Utah
Southam Canyon, Utah
08-H
14-A, 14-D
18. DISTRIBUTION STATEMENT
RELEASE TO PUBLIC
19. SECURITY CLASS (This Report I
UNCLASSIFIED
31. NO. OF PAGES
28
20. SECURITY CLASS (TMspage)
UNCLASSIFIED
22. PRICE
CPA Form 2220-1 (R*v. 4-77) PREVIOUS EDITION is OBSOLETE
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