xvEPA

           United States
           Environmental Protection
           Agency


           Research and Development
            Environmental Research
            Laboratory
            Duluth MN 55804
1 78
Environmental
Effects of Western
Coal Combustion

Part II
The Aquatic
Macroinvertebrates of
Rosebud Creek,
Montana

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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 cate-
gories were established to facilitate further development and application of en-
vironmental  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 ECOLOGICAL RESEARCH series. This series
describes research on the effects of pollution on humans, plant and animal spe-
cies, and materials. Problems are assessed for their long- and short-term influ-
ences. Investigations include formation, transport, and pathway studies to deter-
mine the fate of pollutants and their effects. This work provides the technical basis
for setting standards to minimize undesirable changes in living organisms in the
aquatic, terrestrial, and atmospheric environments.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.

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                                                        EPA-600/3-78-099
                                                        November 1978
         ENVIRONMENTAL EFFECTS  OF WESTERN  COAL  COMBUSTION
Part II - The Aquatic Macroinvertebrates of Rosebud Creek,  Montana
                                 by

                          Steven F. Baril
                       Department of Biology
                     Montana State University
                      Bozeman,  Montana 59717

                         Robert J. Luedtke
                   Fisheries Bioassay Laboratory
                     Montana State University
                      Bozeman,  Montana 59717

                        George  R. Roemhild
                       Department of Biology
                     Montana State University
                      Bozeman,  Montana 59717
                         Grant No. R803950
                          Project Officer

                          Donald I. Mount
                Environmental  Research Laboratory
                      Duluth,  Minnesota 55804
                 ENVIRONMENTAL RESEARCH LABORATORY
                OFFICE OF RESEARCH AND DEVELOPMENT
               U.S. ENVIRONMENTAL PROTECTION AGENCY
                      DULUTH, MINNESOTA 55804

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                                 DISCLAIMER

     This report has been reviewed  by the  Environmental  Research Laboratory,
U.S. Environmental  Protection Agency, and  approved for publication.   Approval
does not signify that the contents  necessarily reflect the views and policies
of the U.S. Environmental Protection Agency, nor does mention of trade names
or commercial  products constitute endorsement or recommendation for  use.
                                      ii

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                                   FOREWORD

     The following report describes the impact of a mine mouth coal-fired
power plant on the macroinvertebrates of Rosebud Creek, Montana.   The study
was limited to a short period of operation after start-up and before all  units
were operating.  Factors such as turbidity and temperature among  others
appeared to cause more change than impact from the power plant.   Other surveys
over time are needed to be sure of the true impacts.


                                       Donald I. Mount, Ph.D.
                                       Director
                                       Environmental Research Laboratory-Duluth

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                                  ABSTRACT

     The aquatic macroinvertebrates of Rosebud Creek, Montana, were sampled
between February 1976 and March 1977 to provide data on their abundance,
distribution, and diversity.  The sampling program was initiated during the
first year of operation of the coal-fired power plants located at Col strip,
Montana.  The purpose of the study was to determine if any immediate impacts
of the power plant operation on the macroinvertebrate communities of Rosebud
Creek could be detected and to provide data for comparisons with future
studies.

     Rosebud Creek supported a diverse bottom fauna with high population
numbers composed of species adapted to the turbid, silty conditions which are
common in the prairie streams of eastern Montana.  Intact riparian vegetation
appeared to be important in maintaining stream bank stability and provided an
essential food source.

     It was concluded that faunal variation among sampling stations during
the study period was attributable to physical  factors including turbidity,
water temperature, current velocity, and substrate, and not to potential
impacts from coal mining and combustion.
                                      IV

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                                  CONTENTS

Foreword	   ill
Abstract	    iv
Figures	    vi
Tables	   vii
Acknowledgments 	    ix

   I  Introduction  	     1

  II  Conclusions 	     3

 III  Recommendations 	     4

  IV  Description of Study Area 	     5

   V  Description of Sampling Stations  	     9

  VI  Materials and Methods	    15

 VII  Results	    17

      Macroinvertebrate Numbers 	    17
      Macroinvertebrate Wet Weights 	    28
      Macroinvertebrate Distribution  	    31
      Diversity and Redundancy  	    57

VIII  Discussion	    64

      Water Chemistry:  Metals  	    64
      Physical Conditions 	    64
      Macroinvertebrate Abundance and Composition 	    67
      Sampling Considerations 	    68

References	    70

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                                   FIGURES
Number                                                                   Page

  1  Benthic invertebrate sampling stations, Rosebud Creek,
     Montana  	     6

  2  Monthly mean discharges for Rosebud Creek at the mouth
     and near Col strip for USGS water years 1975 and 1976	     7
  3  Mean numbers and ranges of aquatic macroinvertebrates
     per sample, March 1976 to March 1977	    21

  4  Mean wet weights and ranges of aquatic macroinvertebrates
     per sample, March 1976 to March 1977	    22

  5  Mean numbers and ranges of aquatic macroinvertebrate
     taxa per sample, March 1976 to March 1977	    23

  6  Significantly different means for total  macroinvertebrates,
     taxa, and wet weights per sample 	    24

  7  Average numbers of aquatic macroinvertebrates per introduced
     substrate sample, May 1976 to March 1977	    26

  8  Average macroinvertebrate wet weights per introduced
     substrate sample, May 1976 to March 1977	    33

  9  Average numbers of selected taxa per introduced substrate
     sample, May 1976 to March 1977	    55

 10  Seasonal variations in mean total  numbers of Hydropsyahe sp.
     B per introduced substrate sample at Stations 1, 5, and 7,
     May 1976 to November 1976	    58

 11  Seasonal variations in mean total  numbers of Dubivaphia minima
     per introduced substrate sample at Stations 1, 5, and 7,
     May 1976 to November 1976	    59

 12  Seasonal variations in mean total  numbers of Choroterpes
     albiannulata per introduced substrate sample at Stations
     1, 5, and 6, May 1976 to November 1976	    60

 13  Total taxa per station and taxa collected by each of three
     sampling methods, March 1976 to March 1977 	    61
                                     VI

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                                   TABLES
Number                                                                   Page

  1  Descriptions and locations of sampling stations,
     Rosebud Creek, Montana 	 	    10

  2  Physical characteristics of sampling locations in 1976 	    11

  3  Physical characteristics of riffle sites in 1976 	    12

  4  Water quality data, means and ranges, March 1976 to
     March 1977	    13

  5  Total numbers of samples from each station by three
     sampling methods, March 1976 to March 1977 	    18

  6  Mean current velocities 7.5 cm from the substrate and
     15 cm upstream of introduced substrate samplers, May 1976
     to March 1977	    19

  7  Average total numbers, wet weights, and numbers of taxa
     of benthic macroinvertebrates, March 1976 to March 1977  	    20

  8  Macroinvertebrate mean total numbers per taxon and mean
     percentages of the sample (introduced substrate), May
     1976 to March 1977	    25

  9  Adult aquatic insects collected along Rosebud Creek
     during 1976	    27

 10  Mean total numbers of aquatic macroinvertebrates per m2
     and average percentages of the sample, March 1976 to
     March 1977	    29

 11  Mean wet weights for macroinvertebrate taxa and average
     percentages of the sample (introduced substrate), May
     1976 to March 1977	    32

 12  Mean wet weights per m2 and average percentages of the
     sample for aquatic macroinvertebrates, March 1976 to
     March 1977	    34

 13  Checklist and distribution of aquatic macroinvertebrates,
     March 1976 to March 1977	    36
                                     vn

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Number                                                                   Page

 14  Number of occurrences and average numbers per occurrence
     for aquatic macroinvertebrates collected in introduced
     substrate samplers, May 1976 to March 1977	    40

 15  Number of occurrences and average numbers per occurrence
     for aquatic macroinvertebrates collected in Ekman dredge
     samples, March 1976 to October 1976  . . . .	    46

 16  Number of occurrences and average numbers per occurrence
     for aquatic macroinvertebrates collected in modified Hess
     samples, March 1976 to March 1977	    50

 17  Mean macroinvertebrate diversities and redundancy per
     sample, March 1976 to March 1977	    62
                                    vi ii

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                               ACKNOWLEDGMENTS

     The writers wish to acknowledge C. J. D. Brown, Rodney K. Skogerboe,
James V. Ward, and Robert V. Thurston for reviewing the manuscript.  We are
grateful to the following experts who checked specimen identifications:
Harley P. Brown (Elmidae), D. G. Denning (Trichoptera), C. Dennis Hynes
(Tipulidae), Dennis M. Lehmkuhl (Ephemeroptera), George Roemhild (Hemiptera
and Zygoptera), John Rumely (grasses), and the USDA Agricultural Research
Service, Beltsville, Maryland (Diptera and Coleoptera).  Access to Rosebud
Creek sampling stations was kindly granted by area residents Don Polich,
Patti Kluver, Wallace McRae, and John Bailey.

     This research was supported by funds provided to the Natural Resource
Ecology Laboratory, Colorado State University, and the Fisheries Bioassay
Laboratory, Montana State University, by the Environmental Research Labora-
tory-Duluth, Environmental Protection Agency, Research Grant No. R803950.
                                      IX

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                                  SECTION I

                                INTRODUCTION

     Expansion of coal mines and construction of coal combustion facilities
for the generating of electricity is underway in eastern Montana.   Two 350-
megawatt electricity generators adjacent to the strip mines at Col strip
became operational in 1975 and 1976; two 750-megawatt power plants  are now
being planned for this same location.  These facilities, and others being
considered for eastern Montana, have the potential to impact the limited
water resources of this region.  Consequently, the need to document the water
quality of the lotic and lentic environments of eastern Montana is  important.
Information obtained can be useful for site planning and construction design
or for modification of existing and proposed power generators bath  in eastern
Montana and elsewhere in the northern Great Plains.

     The benthic macroinvertebrates, an important component of the  aquatic
biota, are primary and secondary consumers in the aquatic ecosystem and are a
food source for fishes and other aquatic animals.  Knowledge of their species
composition, distribution, and relative abundance provides a tool  for mea-
suring water quality.  The present study was undertaken to examine  the
benthic macroinvertebrate community in Rosebud Creek, an eastern Montana
prairie stream which flows within 13 km of Colstrip, and in so doing, flows
into and out of possible environmental impact areas near the Colstrip coal
mine and power plant.  Groundwater from the eastern portion of the  strip mine
fields at Colstrip flows eastward toward Rosebud Creek (Montana State Depart-
ment of Natural Resources, 1974).  The prevailing wind direction is south-
easterly which may result in the deposition of smokestack emissions in the
Rosebud Creek drainage including the north and south forks of Cow Creek, a
small intermittent stream which flows into Rosebud Creek (Skogerboe et al..
1978).  It is not known to what extent the water quality of Rosebud Creek may
be affected by inorganic salts and organic compounds and complexes  resulting
from the coal mining and combustion operation at Colstrip.

     There is little published information on the physical and biological
characteristics of north-central United States prairie streams.  Tradition-
ally, streams of the midcontinent (Kansas, Nebraska, South Dakota)  have been
considered typical of the prairie.  Jewell (1927) described the aquatic
biology of the prairie and presented a description of a typical prairie
stream.  McCoy and Hales (1974) surveyed the physical, chemical, and biologi-
cal characteristics of eight eastern South Dakota streams.  Limnology of
major lakes and drainages was summarized for the midcontinent states by
Carlander et al. (1963) and for Minnesota and the Dakotas by Eddy (1963).
Limnology of these regions may be similar in many respects to that  of eastern
Montana due to similar topographies and climates.


                                      1

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     In the more immediate vicinity of Rosebud Creek, Clancy (1978) has sur-
veyed the benthic fauna of Sarpy Creek, a small ephemeral stream which flows
northward into the Yellowstone River, northwest of Col strip.  East of the
Rosebud drainage, Gore (1975) studied the composition and abundance of the
benthic invertebrates in the Tongue River, and Rehwinkel et al. (1976)
studied the invertebrates of the Powder River.  Both of these rivers also
flow northward into the Yellowstone.  Information has also been provided on
the composition and abundance of benthic macroinvertebrates of the Yellowstone
River by Newell (1976).

     The primary objective of the present study was to obtain information on
the species composition, distribution, and abundance of the benthic macro-
invertebrates of Rosebud Creek during the early operational stages of the
Col strip power plants.  A variety of macroinvertebrate sampling techniques
was used to determine which might be most efficient to sample Rosebud Creek.
The study was conducted between July 1976 and March 1977.  Data obtained will
provide a basis for comparisons with results of future studies of Rosebud
Creek after the present and possible additional power plants at Colstrip have
been operational for some time, and will also add to the current limited
body of knowledge about benthic macroinvertebrate communities in eastern
Montana prairie streams and rivers.

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                                 SECTION II

                                 CONCLUSIONS

1.    Present longitudinal variations in abundance,  distribution,  and  compo-
     sition of the benthic invertebrate fauna in Rosebud Creek  are  attributed
     to the intrinsic physical-chemical characteristics of the  stream:
     i.e., temperature, turbidity, substrate, and current velocity.   There
     was no evidence that these variations were attributable to influences
     from coal mining and combustion.

2.    Rosebud Creek supports an abundant benthic invertebrate fauna  which  is
     adapted to the conditions (i.e.,  high turbidity, slow current  velocity,
     warm summer water temperature, and silted substratum) of a transition
     prairie stream; however, increased severity of these conditions  cor-
     responds with decreased numbers and diversity of less tolerant species
     at downstream stations.

3.    Intact riparian vegetation, particularly grasses, stabilizes the banks
     of Rosebud Creek and prevents serious erosion, sedimentation,  and the
     consequential unproductive shifting substrate common in many prairie
     streams.

4.    Introduced substrate samplers were efficient in collecting taxa  from
     long, slow stretches common in Rosebud Creek and provided a reliable
     method for comparing invertebrate populations among sampling stations.
     A modified Hess sampler was inadequate for this type of stream due to
     insufficient riffle habitat for sampling.  The Ekman dredge, effective
     only for sampling areas of fine substrate, provided less information
     than did introduced artificial substrates.

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                                 SECTION III

                               RECOMMENDATIONS

1.   Because of the projected increase in coal mining and combustion opera-
     tions in and near the Rosebud Creek drainage, and the resultant poten-
     tial  for disturbance of the aquatic fauna, monitoring of the aquatic
     macroinvertebrate fauna in Rosebud Creek should continue.   Future
     studies should be conducted on a year-round basis and should include
     comprehensive monitoring of water chemistry.

2.   Future coal mining, agriculture, and other activities in the vicinity of
     Rosebud Creek and tributary streams should ensure maintenance of a
     buffer zone of riparian vegetation and grasses to minimize erosion.

3.   It is recommended for future surveys that the uppermost (control)
     sampling station of this study be located downstream where ecological
     conditions are more comparable to the other stations, and that the
     lowermost sampling station be moved farther upstream for the same
     reason.  Physical and biological characteristics of the lowest station
     in the present study showed influence of the Yellowstone River.

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                                 SECTION IV

                          DESCRIPTION OF STUDY AREA

     Rosebud Creek originates on the east slope of the Wolf Mountains in
Bighorn County, Montana, in the Crow Indian Reservation.  It then flows
northeast through the Northern Cheyenne Indian Reservation and privately
owned lands for approximately 370 stream kilometers before joining the
Yellowstone River near Rosebud, Montana (Figure 1).  The total area drained
is approximately 3,372 km2 (U.S. Geological Survey, 1976).  An alluvial plain
about 0.8 km wide supports a sparsely populated, agriculturally oriented
economy.  Alfalfa, wild hay, and cereal grains are cultivated, and the stream
provides water for irrigation and livestock.

     The headwaters of Rosebud Creek are erosional in nature; there is a
steep gradient (4.8 m/km) with a riffle-pool system that is similar to many
mountain streams.  After leaving the mountains near the town of Busby and
flowing onto the plains, the gradient decreases (2.5 m/km) and the stream
becomes depositional in nature.  Long, slow reaches with sand or gravel
bottoms predominate, and silted areas are,common.  Suspended and dissolved
solids also increase progressively downstream.

     The shallow valley of Rosebud Creek is cut in sedimentary layers of the
Tertiary period.  Relief is composed mainly of strata from the Paleocene
epoch, specifically sandstones, shales, and coal of the Fort Union formation
which erode at moderate rates.  Coal outcrops have burned in the middle and
upper Rosebud drainage and have metamorphosed adjacent layers producing beds
of highly fractured clinker, red to lavender in color, often incorrectly
called scoria (Renick, 1929).  This material is highly resistant to weathering
and forms much of the substratum of Rosebud Creek.

     Alluvial soils of the floodplain and adjacent low terraces generally
consist of Havre and 61 endive loams, Harlem silty clay loams, and aerie
fluvaquents.  These form deep, calcareous soils of good water-holding capacity
subject to moderate erosion.  Areas of moderately saline soil are present
along the floodplain (L. Daniels, U.S. Soil Conservation Service, Forsyth,
Montana, personal communication).

     Mean monthly flows for Rosebud Creek from October 1974 to September 1976
are shown in Figure 2.  Normal peak flows occur during the spring resulting
from snowmelt runoff.  Rapid fluctuations in discharge can occur during
spring and summer because of rainfall.  The historical mean annual flow is
35.8 cfs (1.01 m3 per sec); mean flow for March, the month of maximum flow,
is 84.3 cfs (2.39 m3 per sec); and the mean flow for September, the month of
minimum flow, is 6.4 cfs (0.18 m3 per sec).  Records show approximately

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                          Ytllowtton*   livtr
                                        ,/*%
                                        ot«b
                            l-7»Somplt  Slt««
                                   10
20    30
                                  Kilomtt«rs
Figure 1.   Benthic invertebrate sampling stations,
              Rosebud Creek, Montana.

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O  300
UJ
CO
UJ
Q.


UJ  200
Ul
u.

o
CD
O

UJ
o
    100
          1974
                                                      1976
                                                        NEAR MOUTH

                                                        NEAR COLSTRIP
          ONDJ  FMAMJJASONDJ  FMAMJJ  AS

                                    MONTH
Figure 2.  Monthly mean discharges for Rosebud Creek at the mouth and near
Colstrip for USGS water years 1975 and 1976  (U.S. Geological Survey,  1976,
1977)

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3000 cfs (84.9 m3 per sec) in March and periods of "no flow" in dry years
(U.S. Geological Survey, 1976, 1977).

     Water temperature records in July and August range from 21°C to a maxi-
mum on record of 26.7°C; minimum temperatures are at freezing for many days
during winter months (Aagaard, 1969) and the stream is usually frozen over
from December to mid-February.

     Riparian vegetation includes mixed grass, boxelder (Aaev rusgundo L.),
green ash (Fvaxinus pennsylvaniaa Marsh), chokecherry (Prunus sp.), rose
(Rosa spp.), willow (Salix spp.), and buffaloberry (Shepherdia sp.).  Common
grasses are reed canarygrass  (Phalaris arundinacea L.), prairie cordgrass
(Spc&tina peatinata Link.), smooth brome (Bvomus inevmis Leys.), and American
bulrush (Seivpus amsriaanus Pers.), all rhizomatous in character and especi-
ally important in streambank  stability.  Streamside vegetation is generally
intact which provides good wildlife habitat and aids in soil stabilization.

     Rosebud Creek is characterized by heavily vegetated banks, extensive
organic deposits in the substrate and a moderately diverse benthic fauna with
high population numbers.  These features are atypical of traditional prairie
streams, which have been described as being nearly devoid of benthic life and
having substrates practically free of organic deposits (Carlander et a!.,
1963).  However, Rosebud Creek does have relatively high turbidity, areas of
shifting substrate, and rapid fluctuations in discharge; these character-
istics are descriptive of traditional prairie streams.  Because its headwaters
originate in and flow through mountainous terrain and the lower reaches flow
through a prairie environment, Rosebud Creek can be termed a transition
prairie stream.
                                      8

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                                  SECTION V

                      DESCRIPTION OF SAMPLING STATIONS

     Seven benthic invertebrate sampling stations were established in Febru-
ary 1976 and numbered consecutively upstream (Table 1, Figure 1).   Selection
was made on the basis of concurrent chemical sampling locations (Skogerboe
et al., 1978), physical similarity, access, and potential for evaluating
impacts from coal development.  An attempt was made to include three habitat
types (riffles, hard-bottom slow stretches, and pools) at each station.

     Station 1 was downstream from the theoretical plume emission fallout
area from the Col strip stack.  Stations 2 through 5 were within the primary
theoretical plume fallout area.  In addition, Stations 3 and 4 bracketed Cow
Creek to evaluate potential effluents from that source.  As a control, Sta-
tion 6 was established upstream from the theoretical plume fallout area.
Rosebud Creek at Station 7 was similar in nature to a mountain stream and
provided information concerning longitudinal changes in the invertebrate
community of the Rosebud Creek system.

     In addition to other physical parameters a subjective evaluation of the
predominant substrate type at each station was made utilizing the classifi-
cation of Cummins (1962) (Table 2).  Station 1 is unique in having a sub-
strate of washed rubble and boulder from Yellowstone alluvium and a riffle-
pool habitat caused by an increase in gradient as Rosebud Creek enters the
Yellowstone Valley.  Typical substrate at Station 2 consists of flocculent
clay or silt with gravel common only in meanders at the valley edge.  Stations
3, 4, and 5 have long meandering stretches with slow current velocity and a
substratum of gravel, sand, and silt.  Station 6, in addition to long, slow
stretches, has sections of clean, rubble-bottom riffles alternating with
sand-bottom pools.  The substrate at Station 7 consists mainly of gravel and
rubble in riffles and sand in pools.

     Shallow riffles for bottom sampling were not common at Stations 2
through 5; however, riffle sampling sites were established at Stations 1, 3,
5, 6, and 7; physical parameters are given in Table 3.  The riffle at Station
3, due to depth, was sampled only during periods of low flow.

     As shown in Table 4, Rosebud Creek waters are alkaline with a very basic
pH and a high concentration of electrolytes.  The water is a carbonate-
sulfate-magnesium type and unusual due to the higher concentration of mag-
nesium than calcium.  Dissolved oxygen is near saturation throughout the
year.

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       TABLE 1.   DESCRIPTIONS AND LOCATIONS OF SAMPLING STATIONS,
                         ROSEBUD CREEK,  MONTANA

Station
1
2
3
4
5
6
Elevation
(m)
756
814
869
869
896
960
Kilometers from
Yellowstone River
0.7
15.4
29.7
30.0
36.8
51.4
Legal description
NE1/4 Sec 21 R42E T6N
SW1/4 Sec 30 R43E T4N
NE1/4 Sec 5 R43E TIN
SE1/4 Sec 5 R43E TIN
NW1/4 Sec 34 R42E TIN
SW1/4 Sec 8 R41E T2S
Description
U.S.G.S gauging station near
1-90
Pollen ranch
Kluver ranch, 480 m down-
stream of Cow Creek
Kluver ranch, 680 m upstream
of Cow Creek
W. McRae ranch
Bailey ranch, border of
                                                         Northern Cheyenne  Reservation
1195
85.8
NW1/4 Sec 29 R39E T6S
Near Kirby at Highway 314
culvert

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                                      TABLE 2.   PHYSICAL CHARACTERISTICS OF SAMPLING LOCATIONS IN 1976

Mean width (m)
Mean depth (m)
Valley gradient
(m/km to next site)
Stream gradient
(m/km to next site)
Mean turbidity
(nephelometric units)
Temperature (°C)
Mean August maximum
Mean August minimum
Mean October maximum
Mean October minimum
Substrate^
Vegetation-2/

1 2
7.5 5.0
0.4 0.7
2.46 2.38
1.32 1.09
11.4 9.5
23.4
19.3
4.1
2.1
40,60,0,0,0 0,40,10,10,40
0,1,99 73,5,22
Station
3456 7
4.2 3.6 5.5 6.1 2.5
0.6 0.7 0.8 0.6 0.4
2.39 2.39 2.74 4.80
0.99 0.99 1.01 1.60
4.9 4.7 4.5 4.9 5.5
22'; 0 19.5 20.0
20.4 17.4 15.9
3.7 5.2
2.8 3.5
10,60,10,20,0 0,70,0,20,10 10,50,20,20,0 30,30,30,10,0 10,40,30,20,0
18,5,77 6,4,90 18,20,62 13,41,46 28,33,39
-'Composition (%) in the following sequence:   rubble, gravel,  sand,  silt,  clay.
-Composition (%) in the following sequence:   trees,  shrubs,  grass.

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TABLE 3.  PHYSICAL CHARACTERISTICS OF RIFFLE SITES
                      IN 1976


Mean current
velocity (m/sec)
Mean depth (m)
Substrate

1
0.52
0.18
rubble,
boul der
Station
3 5
0.35 0.39
0.31 0.16
rubble gravel

6 7
0.51 0.46
0.17 0.09
rubble rubble
                        12

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                               TABLE 4.  WATER QUALITY  DATA,-''  MEANS  AND  RANGES  (IN  PARENTHESES),  MARCH 1976 TO MARCH 1977
u>

pH
Specific conductivity
(umhos)
Alkalinity
(rng/1 CaC03)
Suspended solids
(mg/1)
Dissolved solids
(mg/l)
Dissolved oxygen
(mg/D
Da2* (mg/1)
NO; (mg/1)
P03-M (mg/1)
SO" (mg/1)
Cl~ (mg/1)
As Ug/1)
Cu (mg/1)
Dissolved Fe
(mg/D
~ ~ ' "*" " ~ ~ 	 '"
1
8.45
(8.12-8.80)
1364.0
(558-1798)
409.6
(313-492)
534.0
(7.9-4308.0)
965.0
(431-1367)
9.8
(7.4-12.1)
84.3
(45-150)
0.18
(0.14-0.21)
0.53
(0.02-5.00)
404.0
(160-605)
a. 2
(2.1-28.0)
2.7
(1.1-9.5)
0.007
(0.005-0.010)
0.04
(0.01-0.11)
— — 	 . 	
2
8.49
(8.17-8.81)
1282.0
(539-1531)
396.0
(298-498)
267.0
(10.1-1494.0)
878.0
(697-1335)
9.8
(6.9-12.3)
82.8
(37-140)
0.13
(0.12-0.13)
0.25
(0.02-1.70)
358.0
(160-515)
5.8
(2.7-10.0)
2.64
(1.0-8.4)
0.015
(0.003-0.074)
0.04
(0.01-0.13)

3
8.49
(8.09-8.70)
1281.0
(856-1496)
398.0
(294-480)
99.0
(9.8-459.0)
845.0
(610-980)
9.6
(6.7-11.6)
88.4"
(56-140)
0.09
(0.08-0.09)
0.14
(0.02-0.40)
336.0
(250-405)
5.2
(2.8-8.0)
1.77
(1.0-3.6)
0.012
(0.003-0.046)
0.06
(0.01-0.16)
Station
4
8.51
(8.08-8.76)
1274.0
(967-1437)
404.0
(341-488)
100.0
(10.8-463.0)
816.0
(591-1000)
9.8
(7.0-12.3)
90.4
(56-140)
0.08
(0.06-0.10)
0.12
(0.02-0.30)
325.0
(180-375)
5.1
(3.0-8.0)
1.64
(0.9-3.2)
0.010
(0.003-0.059)
0.06
(0.01-0.18)

5
8.52
(8.17-8.91)
1241.0
(954-1435)
402.0
(323-486)
154.0
(7.7-629.0)
814.0
(586-1080)
9.6
(7.1-12.4)
89.3
(56-140)
0.05
(0.05-0.05)
0.13
(0.02-0.30)
336.0
(204-540)
5.0
(3.0-8.5)
1.92
(0.4-4.4)
0.008
(0.003-0.027)
0.05
(0.01-0.13)

6
8.47
(8.12-8.85)
1164.0
(978-1325)
412.0
(348-490)
129.0
(5.4-573.0)
744.0
(598-960)
9.7
(7.3-12.9)
87.4
(55-130)
0.05
(0.05-0.05)
0.16
(0.02-0.75)
270.0
(155-400)
5.0
(3.0-11.0)
1.95
(0.6-5.2)
0.008
(0.003-0.043)
0.03
(0.01-0.10)

7
8.47
(8.15-8.81)
911.0
(846-979)
383.0
(325-425)
26.0
(6.3-68.0)
572.0
(500-780)
11.2
(9.2-12.2)
100.3
(75-110)
—
0.09
(0.04-0.15)
151.0
(110-260)
3.4
(1.5-7.0)
1.3
(0.9-2.4)
0.005
(0.003-0.006)
0.04
(0.02-0.05)

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               TABLE 4 (continued).  WATER QUALITY DATA,5/ MEANS AND RANGES (IN PARENTHESES), MARCH 1976 TO MARCH 1977


Undissolved Fe
(mg/1)
Hg (ug/D
K (mg/1)
Mg (mg/1)
Mr) (mg/1)
Na (mg/1)
Ni (mg/1)
Se (ug/1)
Zn (mg/1)

1
6.88
(0.25-44.0)
1.68
(0.07-10.3)
13.3
(7.4-23.0)
115.0
(30-190)
0.014
(0.001-0.05)
166.0
(60-740)
0.004
(0.003-0.005)
0.48
(0.3-0.8)
0.012
(0.001-0.032)

2
2.97
(0.24-17.0)
1.75
(0.12-9.4)
13.2
(8.5-23.0)
110.0
(30-190)
0.036
(0.001-0.32)
80.0
(45-100)
0.005
(0.003-0.011)
0.49
(0.3-0.7)
0.012
(0.001-0.050)

3
1.34
(0.16-4.3)
3.08
(0.05-16.0)
13.0
(7.8-22.0)
117.0
(69-170)
0.014
(0.001-0.05)
72.0
(45-90)
0.007
(0.005-0.030)
0.43
(0.3-0.6)
0.045
(0.001-0.380)
Station
4
1.26
(0.20-3.7)
2.40
(0.05^-18.3)
12.9
(7.7-22.0)
116.0
(79-170)
0.012
(0.001-0.05)
71.0
(43-87)
0.008
(0.003-0.040)
0.49
(0.3-0.6)
0.011
(0.001-0.048)

5
1.88
(0.18-7.6)
1.65
(0.10-15.0)
12.7
(7.6-21.0)
112.0
(86-180)
0.016
(0.001-0.05)
66.0
(58-85)
0.005
(0.002-0.010)
0.43
(0.03-0.7)
0.014
(0.001-0.090)

6
1.94
(0.20-7.6)
1.07
(0.05-9.0)
11.9
(7.3-19.0)
108.0
(78-160)
0.020
(0.001-0.056)
53.0
(44-66)
0.006
(0.002-0.020)
0.51
(0.4-0.7)
0.007
(0.001-0.017)

7
0.52
(0.23-1.1)
0.36
(0.05-0.29)
7.0
(5.0-9.2)
67.0
(61-74)
0.028
(0.003-0.05)
22.0
(17-25)
0.005
(0.005-0.005)
0.44
(0.3-0.5)
0.011
(0.001-0.034)
^/Collected and determined by the Fisheries Bloassay Laboratory, Montana State University, Bozeman, Montana, and the Natural
  Resource Ecology Laboratory, Colorado State University, Fort Collins, Colorado.

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                                 SECTION VI

                            MATERIALS AND METHODS

     Sampling was initiated in March 1976 using a modified Hess sampler
(Waters and Knapp, 1961) to sample riffles.  An Ekman dredge fastened to a
steel handle and with a manual closing release was used to sample pools.
Substrate in baskets was introduced in hard-bottom slow stretches, a common
habitat of Rosebud Creek, for colonization by macroinvertebrates.

     Baskets, constructed from 1.27 cm hardware cloth, had dimensions of 15 x
15 x 30 cm and were filled with 40 pieces of hand-sorted clinker measuring 5
to 8 cm along the longest axis.  At each station two samplers were anchored
on the bottom at similar depth and current velocity.  The samplers were
allowed to be colonized for 6 weeks, and samples were then collected monthly.
The sampling procedure involved placing a nylon dip net (1 mm mesh) immedi-
ately downstream to catch organisms dislodged as the sampler was lifted.
Debris on the anchoring stake or basket handle was discarded, but debris
clinging to the sampler was collected.  Substrate was removed and scrubbed
with a brush.  For each sample, current .velocity was determined using a
Gurley (Model 625-F) current meter 15 cm in front of the basket; depth was
also measured.  A subjective evaluation was made concerning the amount of
sediment and debris in the sampler.  Baskets were sampled monthly from May to
November 1976, and in March 1977.  Because of continuous ice cover the
samplers were removed from December 1976 to February 1977.

     Two 0.023 m2 Ekman dredge samples were taken at each station during
March, June, August, and October 1976.  Two 0.093 m2 Hess samples were taken
at Stations 1, 5, 6, and 7 in March, June, August, and November 1976, and in
February and March 1977.  Samples were collected at Station 3 in August and
November 1976 and March 1977, using a modified Hess sampler.  Qualitative
samples were collected at various locations at each station using a dip net.
All samples were preserved initially in 10% formalin.

     Samples were later screened through a No. 30 U.S.A. Standard sieve (11.0
meshes/cm, 0.589 mm opening) and organisms were hand-sorted and stored in 7Q%
ethanol.  Invertebrates were identified to genus or species where feasible
and possible, using keys by Brown (1972), Edmunds et al. (1976), Gaufin
et al. (1972), Jensen (1966), Johannsen (1934, 1935), Needham and Westfall
TT95T), Pennak (1953), Roemhild (1975, 1976), Ross (1944), and Usinger (1971).
Specimens were sent to recognized taxonomic experts for confirmation of
identifications.  To aid in identifications, emerging adult insects were
collected and some naiads were reared to adults in an artificial stream at
Montana State University.  Wet weight of the collections was determined with
a Mettler Type B5 analytical balance following the procedure of Slack et al.
(1973).

                                     15

-------
     Species diversity was calculated using the Simpson Index (Simpson,
1949), the Margalef Index (Margalef, 1957), and the Shannon Index (Patten,
1962) as modified by Hamilton (1975).  Calculations were performed using the
Montana State University Sigma 7 computer.

     In August 1976, stream width and thalweg depth at each station were
recorded at 10 locations 50 m apart.  In addition, a subjective evaluation
was made concerning substrate and riparian vegetation compositon at each
location.  At the riffle sites, water depth and current velocity 5 cm from
the substrate were measured at 30 cm intervals along transects spaced 2 m
apart.

     Water samples were collected for turbidity analyses in October and
November 1976 and February 1977.  Determinations were made using a nephelom-
eter (HF Instruments, Model DRT 200), following the procedure given by the
American Public Health Association  (1976).

     Continuous recording thermographs (Ryan Model D-15) were utilized at
Stations 1, 3, 5, and 7 during 10-25 August and 16-31 October 1976.
                                     16

-------
                                 SECTION VII

                                   RESULTS

     The total number of samples collected at each station by each sampling
method is given in Table 5.  Mean current velocities immediately upstream
from the introduced substrate samplers are given in Table 6.  Aquatic macro-
invertebrate abundance in terms of average total numbers of individuals,  wet
weight, and number of taxa is shown in Table 7 and Figures 3, 4, and 5.
Analysis of variance of these parameters based on the method of unweighted
means (Snedecor and Cochran, 1967) showed that station means were signifi-
cantly different (a = 0.01) for total numbers of individuals, wet weight, and
number of taxa.  Means were grouped according to the Newman-Keuls sequential
comparison test (Snedecor and Cochran, 1967) (Figure 6).  Results from
modified Hess samples for Station 3 were not analyzed statistically due to
the small number of samples.

     Pool habitats in Rosebud Creek supported a smaller standing crop than
riffles.  Average wet weight per m2 was 10.8 g in riffles and 2.9 g in pools.
The mean number of individuals per m2 was 6007 in riffles and 4993 in pools;
these nearly corresponding numbers were due to the abundance of low-mass
individuals (e.g., Chironomidae and Oligochaeta) in pools.

MACROINVERTEBRATE NUMBERS

     Invertebrate numbers were generally greater at Stations 5, 6, and 7
relative to Stations 2, 3, and 4.  Station 1 normally had higher numbers  than
Stations 2, 3, and 4.

Introduced Substrate Samplers

     Analysis of introduced substrate samples gave results (Table 7) consis-
tent with the trends mentioned above.  Average number of macroinvertebrates
per sample was greatest at Stations 5 and 6 and lowest at Station 2.  Numeri-
cal abundance was similar at Stations 1 and 7.  Likewise, Stations 3 and  4
were similar and supported low numbers of individuals.

     Average total numbers per taxon and relative average percent of the
total sample is presented in Table 8 and Figure 7.  Trichoptera, comprised
mainly of Hydropsychidae, were the most common invertebrates at most stations,
constituting from 22% of the total sample at Station 3 to 55% at Station  5.
Cheumatopsyehe spp. were abundant at all stations; Cheianatopsyche lasia
(Ross) may be a dominant species, as adults (Table 9) were commonly collected
at all stations.  A Hydropsyche spp. complex of at least four species was
abundant at most stations.  Lower numbers of Trichoptera were present at


                                      17

-------
      TABLE 5.  TOTAL NUMBER OF SAMPLES FROM EACH STATION
      BY THREE SAMPLING METHODS, MARCH 1976 TO MARCH 1977
                                         Station
                          1
Introduced substrates    13    15    15    15    15    15    15
Ekman dredge              8888888
Modified Hess            12     0     6     0    12    12    12
                                18

-------
          TABLE 6.  MEAN CURRENT VELOCITIES 7.5 CM FROM THE
        SUBSTRATE AND 15 CM UPSTREAM OF INTRODUCED SUBSTRATE
                  SAMPLERS, MAY 1976 TO MARCH 1977
                                         Station

                    123        4567


Current velocity   0.36    0.42   0.46     0.38    0.50    0.38    0.41
(m/sec)
                                   19

-------
   TABLE 7.   AVERAGE TOTAL NUMBERS, WET WEIGHTS,  AND NUMBERS OF
          TAXA OF BENTHIC MACROINVERTEBRATES,  MARCH 1976
                           TO MARCH 1977



Average total
numbers





Average wet weight
(g)





Average total taxa









Station
1
2
3
4
5
6
7
1
2
3
4
5
6
7
1
2
3
4
5
6
7


Introduced
substrates^
1090
830
994
953
1633
1317
1029
1.92
3.25
1.72
1.84
2.75
2.29
3.17
20.9
16.3
19.0
18.9
22.5
24.0
22.9


Ekman
dredge-'
4402
2077
4774
4876
7664
3073
8076
2.20
1.98
0.95
3.23
2.07
1.03
8.74
6.5
7.1
5.6
8.8
10.5
5.8
5.4


Modified
Hess*/
6852

5278

2081
8690
7134
12.49

6.24

2.15
9.15
24.11
15.4

13.5

10.7
18.6
19.1

^Average total numbers and wet weights .per sample.

-'Average total numbers and wet weights per m2.
                                  20

-------
      2000
   UJ
   QL

   Q   1000


   <

   LJ
   _l
   0.
   cc
   Ul
   CL
   CO
   UJ
   a:
   m
   UJ
   H
   o:
   ut
       400
200
   CE
   UJ
   m
      2OOO
      1000
                                        3783
                                        3498
            INTRODUCED  SUBSTRATES
            EKMAN  DREDGE
            MODIFIED HESS
                            345

                         SAMPLING STATIONS
Figure 3.   Mean  numbers  (horizontal line) and ranges  (vertical bar)
        of aquatic macroinvertebrates per sample,  March  1976
                         to March 1977.
                                21

-------
      6.0
      4.0
      2.0
CO
5
tr


e>
z
(T

i  o-
<
LJ
Q.
   CO

   cc
   UJ
   Q.

   CO
   CO
   o
   m
      0.2
      4.0
      2.0
          INTRODUCED  SUBSTRATE
                  8.81
                                             6.68
                                                       8.02
          EKMAN DREDGE
                                            -B-
                                                       6.47
          MODIFIED HESS
                                        •S-
                          345

                       SAMPLING STATIONS
Figure 4.  Mean wet weights  (horizontal  line)  and ranges (vertical
         bar) of aquatic macroinvertebrates  per sample,
                    March 1976 to March  1977.
                                22

-------
   30
   20
    10
UJ
o
CC

O
z
UJ

0.
2
<
OT

oc
UJ
a.
u.
o

cc
UJ
CD
5  20
    10
2O
    10
       INTRODUCED SUBSTRATE
    EKMAN DREDGE
            ...    n
       MODIFIED HESS
                       345

                      SAMPLING  STATIONS
Figure 5.  Mean numbers  (horizontal line) and ranges (vertical
      bar) of aquatic  macroinvertebrate taxa per sample,
                   March 1976 to March 1977.
                             23

-------
         INTRODUCED SUBSTRATE:

               1       2
w
T
MW


TW
T
TW
MT
W
u

TW
T
MTW


TW
T
MTW

M
M

U

         7

         6

         5

         4

         3

         2
EKMA
7
6
5
4
3
2
N DREDGE:
1 234 56
MW

T



MW

MT



MW

T
T

MW



TW MW
MT

         MODIFIED HESS:

               1      5

         7             TW

         6             MT

         5      MT
Figure 6.  Significantly  different means^-1^ for total
 macroinvertebrates, taxa,  and wet weights per sample.
-'M, T, and W indicate  a  significant difference (0.05) for
  mean total macroinvertebrates, taxa, and wet weight,
  respectively.  Where  symbols are absent, no real difference
  existed.

— Compare stations  in the left vertical column with those in
  the horizontal row.
                              24

-------
cn
           TABLE 8.  MACROINVERTEBRATE^  MEAN  TOTAL  NUMBERS  PER  TAXON  AND  MEAN  PERCENTAGES^/  OF  THE
                              SAMPLE  (INTRODUCED  SUBSTRATE),  MAY  1976 TO  MARCH  1977
Station Ephem.
1 85
(7.8)
2 65
(7.8)
3 192
(19.3)
4 162
(17.0)
5 203
(12.5)
6 185
(14.1)
7 83
(8.1)
Odon./
Zygop.
3
(0.3)

-------
       800
       700
   UJ


   (T   60O
   m
   O   500
   UJ
   o
   o
   o
   cr
   UJ
   a.


   a:
   UJ
   m
       400
3OO
       200
       100
                   • Trichoptera
                    Dipt era
         -— Ephemeroptera

          	Coleoptera
902
                                34         5

                             SAMPLING STATIONS
Figure 7.  Average  numbers of aquatic macroinvertebrates per introduced
               substrate sample, May 1976 to March  1977.
                                     26

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       TABLE 9.  ADULT AQUATIC INSECTS COLLECTED ALONG ROSEBUD CREEK
                                DURING 1976
Ephemeroptera
  Baetidae
    Bast-is (near pvopinquus)
  Leptophlebiidae
    Chovoterpes afbiannulata McDunn.

Odonata
  Gomphidae
    GompTms externus Hagen
  Libellulidae
    Sympetrwn oocidentdle Wai ker

Zygoptera
  Coenagrionidae
    Argia fumipennis-violaaea  (Hagen)
    Isohnura perparva  (Selys)
  Calopterygidae
    Hetaeri-na americana  (Fabricius)

Hemi ptera
  Gerridae
    Gerris remiges Say
  Veliidae
    Rhagovelia distineta Champion
Trichoptera
  Hydropsychidae
    Bydpopsyohe "bvonta Ross
    Hydrops-yahe separata Banks
    Avatopsyehe sp.
    Cheumatopsyche las-la Ross
    Cheumatopsycke anal-Ls (Banks)
    Cheumatopsydhe campy la ROSS
  Psychomyiidae
    Polyeentropus cineveus Hagen
  Leptoceridae
    Oeeet-is avara (Banks)
    Leptcoella albida
    Leptocella (near Candida]
  Brachycentridae
    Brachyeentrus oeeidentalis Banks

PIecoptera
  Nemourldae
    Braetyptera foskett-i Ricker
  Perlodidae
    Isopevla patvieia Prison

Diptera
  Tabanidae
    Chryaops proalivis Osten Sacken
  Tipulidae
    Tipula v-icina Dietz
                                       27

-------
most stations.  Lower numbers of Trichoptera were present at Stations 2,  3,
and 4.  Diptera, particularly Chironomidae, were the next most abundant
taxon.  Highest numbers were collected at Stations 3 and 6; fewer individuals
were present at Stations 1, 2, and 4.  Ephemeroptera were most common at
Stations 3 and 4 where Choroterpes albiannulata was the major species.
Coleoptera appeared to increase in numbers from Station 2 through 6, then
declined at Station 7.  Plecoptera were uncommon in basket samples and were
numerous only at Station 7, the most upstream location.  Molluscs were most
abundant at Stations 2, 6, and 7, and Hemiptera were most common in the mid-
Rosebud (Stations 2 through 6).  Oligochaeta appeared to increase in abundance
progressively upstream.

Ekman Dredge Samples

     Mean numbers of aquatic macroinvertebrates collected with an Ekman
dredge from pools are given in Table 7.  Macroinvertebrate populations per m2
were most dense at Stations 5 and 7 while Stations 2 and 6 supported the
lowest numbers.  Stations 1, 3, and 4 supported similar total population
numbers.

     Average total numbers per taxon is presented in Table 10.  Diptera were
the most common macroinvertebrates collected, and ranged from 51 to 84% of
the total sample at each station; numbers were highest at Stations 5 and  7
and lowest at Station 2.  Oligochaetes, the next most common group in Ekman
samples, were found in high numbers at Stations 1 and 7; Stations 2 and 3
supported the lowest populations.  Molluscs were collected in significant
numbers only at Stations 2, 3, and 4.  Coleoptera, particularly Dubivaphia
minima, comprised a large portion of the benthic population in pools and  were
common at Stations 1 through 5.  Trichoptera were found in highest numbers at
Station 5.  Other taxa were uncommon and Plecoptera were absent from Ekman
dredge samples.

Modified Hess Samples

     Macroinvertebrates were most abundant at Station 6 and least abundant at
Station 5 (Table 7).  Stations 1 and 7 were similar in population densities.
Average total numbers per taxon and relative percent of the total sample  are
presented in Table 10.  Diptera were numerically the most abundant taxon
collected by this method and highest numbers were present at Station 6.
Trichoptera, the next most numerous taxon, were most common at Station 7  and
least at Stations 3 and 5.  Taxa were often collected in low numbers at
Station 5.

MACROINVERTEBRATE WET WEIGHTS

     Wet weight usually reflected numbers of individuals; however, certain
species of large body size contributed disproportionately to the sample
weight.  For example, at Station 2 numerous Mollusca, Anbrysus mormon, and
Hydropsychidae resulted in high average wet weight per introduced substrate
sample even though total numbers of macroinvertebrates were low.  Although
general trends for distribution of wet weight among stations were not evi-
dent, Station 7 consistently supported high biomass.

                                      28

-------
PO
UD
               TABLE 10.  MEAN TOTAL NUMBERS OF AQUATIC MACROINVERTEBRATES^/ PER M2 AND AVERAGE

                             PERCENTAGES OF THE SAMPLED MARCH 1976 TO MARCH 1977

Station Ephem.

1 5
2 22
(1.0)
3 59
(1.2)
4 183
(3.7)
5 204
(2.7)
6 38
(1.2)
7 31
(0.4)
Odon./
Zygop.

11
(0.2)
16
(0.8)
5
(0.1)
32
(0.7)
11
(0.1)
32
(1.1)
6
(0.1)
Plecop.

0
0
0
0
0
0
0
Trich.
Skman
70
(1.6)
86
(4.1)
32
(0.7)
129
(2.6)
603
(7.9)
151
(4.9)
117
(1.4)
Coleop.
dredge
963
(21.9)
425
(20.5)
651
(13.6)
850
(17.4)
672
(8.8)
124
(4.0)
283
(3.5)
Dipt.

2179
(49.5)
1130
(54.4)
3190
(66.8)
2905
(59.6)
5902
(77.0)
2577
(83.9)
5896
(73.0)
Oligo.

1124
(25.6)
344
(16.6)
780
(16.3)
699
(14.3)
248
(3.2)
145
(4.7)
1722
(21.3)
Moll us.

11
(0.2)
54
(2.6)
48
(1.0)
48
(0.9)
0
0
12
(0.2)
Henri p.

38
(0.9)
0
5
(0.1)
5
(0.1)
0
0
0
Modified Hess
I 615
(9.0)
3 2505
(47.5)
2
2
2
(<0.1)
4
(0.1)
2909
(42.5)
362
(6.9)
760
(11.1)
77
(1.5)
2185
(31.9)
2249
(42.6)
349
(5.1)
40
(0.7)
5
(0.1)
18
(0.3)
2
(0.1)

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   TABLE 10 (continued).   MEAN TOTAL NUMBERS OF AQUATIC MACROINVERTEBRATES^  PER M2 AND AVERAGE

                       PERCENTAGES OF THE SAMPLED MARCH 1976 TO MARCH 1977

Station
5
6
7
Ephem.
294
(14.1)
1246
(14.3)
582
(8.2)
Odon./
Zygop.
0
98
(0.1)
109
(0.1)
Plecop.
0
14
(0.2)
32
(0.5)
Trich.
351
(16.9)
2309
(26.6)
4617
(64.7)
Coleop.
126
(6.0)
627
(7.2)
275
(3.9)
Dipt.
1163
(55.9)
4321
(49.7)
1313
(18.4)
Oligo.
128
(6.2)
118
(1.4)
278
(3.9)
Moll us.
0
1
19
(0.3)
Hemip.
(0.3)
9
(0.1)
0

      = Ephemeroptera, Odon = Odonata, Zygop = Zygoptera, Plecop = Plecoptera,  Trich = Trichoptera,
Coleop = Coleoptera, Dipt = Diptera, Oligo = Oligochaeta, Moll us = Mollusca,  Hemip = Henri ptera.

In parentheses.

-------
Introduced Substrate Samples

     Mean wet weight (Table 7) was greatest at Station 2 and lowest at
Station 3.  Average wet weight per sample was also high at Stations 5 and 7.

     Average wet weight and percent of the total sample for certain taxa are
presented in Table 11 and Figure 8.  Trichoptera was the most common taxon in
most samples; however, in contrast to numbers, weight was low at Station 6
and high at Station 2, indicating differences in average larval size, state
of development, or species composition.  Wet weight per sample for Odonata
and Zygoptera appeared to increase progressively upstream to Station 6.
Ephemeroptera biomass was low at Station 2 and high at Stations 3 through 6
due mainly to large numbers of Chovoterpes alb-lannulata and Ba&t-is spp.  Wet
weights for Diptera were relatively high at all stations, especially 3 and 6.
Coleoptera biomass was higher at Stations 5 and 6 and Plecoptera comprised a
considerable portion of the wet weight only at Stations 6 and 7.

Ekman Dredge Samples

     Macroinvertebrate wet weight per m2 was greatest at Station 7 where high
numbers of Chironomidae were collected (Table 7).  All other stations were
not significantly different.  Average wet weight and relative percent of the
total sample for certain taxa is given in Table 12.  Diptera and Oligochaeta
constituted a large portion of the total wet weight; Diptera biomass was high
at Stations 5 and 7 and Oligochaeta at Stations 1 and 7.

Modified Hess Samples

     Macroinvertebrate wet weight per m2 for modified Hess samples was
highest at Station 7 followed by Station 1 (Table 7); the lowest average wet
weight was found at Station 5.  Average wet weight and percent of the total
sample for certain taxa is presented in Table 12.  The largest portion of
most samples was comprised of Trichoptera with the exception of Stations 3
and 5 where total numbers were also low.  Wet weights for many taxa were low
at Station 5.

MACROINVERTEBRATE DISTRIBUTION

     A checklist of total taxa collected from Rosebud Creek and their respec-
tive distributions with regard to sampling stations is given in Table 13.
The number of occurrences and average number per occurrence for individual
taxa is listed for each sampling method in Tables 14, 15, and  16.  Average
numerical abundance per introduced substrate sampler for common macroinver-
tebrates is shown in Figure 9.  Average numbers and occurrences often tended
to be lowest at Station 2, then increased progressively upstream, often
declining at Station 7.  Numbers were usually greater at Station 1 relative
to Station 2.  Organisms with this pattern of distribution included
Leptophlebia gravastella, Tricorythodes minutus^ Baetis sp. B, Hydroptila
spp., Stenelmis oregonensi-s, Heliahus stviatus, and Heptagen-La elegantula..
Other macroinvertebrates (e.g., Choroterp&s albiannulataf Bvachyptera sp.,
Ambrysits mormon., S-Lmuliwn spp., and Sphaeriwn spp.} appeared to be most
abundant in the mid-Rosebud and did not increase in numbers progressively

                                       31

-------
CO
INJ
            TABLE  11.  MEAN WET WEIGHTS5/  FOR MACROINVERTEBRATE TAXA^/ AND AVERAGE PERCENTAGES5/ OF
                           THE SAMPLE .{INTRODUCED SUBSTRATE), MAY  1976 TO MARCH  1977

Station
1
2
3
4
5
6
7
Ephem.
0.15
(7.6)
0.07
(2.1)
0.23
(13.6)
0.27
(14.6)
0.26
(9.5)
0.37
(16.0)
0.11
(3.6)
Odon./
Zygop.
0.04
(1.8)
0.05
(1.7)
0.06
(3.6)
0.11
(5.9)
0.22
(8.0)
0.35
(15.4)
0.23
(7.4)
Plecop.
0.00
<0.01
(0.1)
<0.01
<0.01
(0.1)
<0.01
(0.1)
0.01
(0.5)
0.08
(2.4)
THch.
1.26
(65.4)
1.95
(60.0)
0.50
(29.3)
0.65
(35.3)
1.51
(54.9)
0.58
(25.3)
2.26
(71.2)
Coleop.
0.05
(2.4)
0.03
(0.8)
0.03
(1.5)
0.04
(2.2)
0.14
(4.9)
0.14
(5.9)
0.04
(1.3)
Dipt.
0.40
(21.1)
0.54
(16.8)
0.74
(43.3)
0.46
(24.7)
0.43
(15.5)
0.67
(29.4)
0.37
(11.5)
Oligo.
<0.01
(0.2)
<0.01
<0.01
<0.01
(0.1)
<0.01
<0.01
(0.1)
0.01
(0.2)
Moll us.
0.03
(1.5)
0.28
(8.7)
0.03
(2.0)
0.25
(13.5)
0.01
(0.3)
0.03
(1.3)
0.05
(1.7)
Henri p.
<0.01
0.32
(9.7)
0.12
(6.7)
0.06
(3.3)
0.18
(6.5)
0.12
(5.4)
0.01
(0.4)

            grams  per  sample.
               =  Ephemeroptera ,  Odon  =  Odonata,  Zygop  =  Zygoptera,  Plecop  =  Plecoptera,  Trich  =
         Trichoptera,  Coleop  = Coleoptera,  Dipt  =  Diptera,  Oligo  »  OUgochaeta,  Mollus = Mollusca,
         Hemip  =  Henri ptera.

       y In parentheses.

-------
UJ

5
(T

w>
03
r>
CO
  UJ
  o
      2.00
      1.80
§  '-60

cc
\-

-  1.40




    1.20
  a:
  UJ
to


£
o
      1.00
  X  0.80
  UJ
  I-
  UJ
  UJ
  o
  <
      0.60
      0.40
     0.20
     0.00
                    Trichoptera
                    Dipt era
                    Ephemeroptera
                    Coleoplera
                                 345

                              SAMPLING  STATIONS
Figure 8.   Average macroinvertebrate wet weights (grams) per  introduced
                substrate  sample, May 1976 to  March 1977.
                                      33

-------
TABLE 12.  MEAN WET WEIGHTS^  PER M2  AND  AVERAGE  PERCENTAGES OF THE SAMPLED FOR AQUATIC
                     MACROINVERTEBRATES,5/  MARCH  1976  TO MARCH 1977

Station Ephem.

1 0.0
2 0.02
(0.8)
3 0.03
(2.8)
4 0.28
(8.7)
5 0.05
(2.6)
6 0.05
(4.8)
7 0.01
(0.1)
Odon./
Zygop.

0.06
(2.9)
0.55
(28.1)
0.02
(2.2)
0.52
(16.1)
0.19
(9.1)
0.51
(49.7)
0.01
(<0.1)
Plecop.

0.0
0.0
0.0
0.0
0.0
0.0
0.0
Trich.
Ekmm
0.18
(8.4)
0.17
(8.7)
0.0
0.69
(21.6)
0.43
(20.6)
0.16
(15.9)
0.74
(8.4)
Coleop.
dredge
0.28
(12.8)
0.12
(6.3)
0.13
(13.4)
0.22
(6.9)
0.18
(8.9)
0.05
(5.3)
0.05
(0.6)
Dipt.

0.53
(24.3)
0.45
(22.6)
0.33
(34.1)
0.23
(7.2)
1.12
(54.2)
0.18
(18.0)
5.94
(67.9)
Oligo.

1.10
(50.1)
0.28
(14.2)
0.35
(36.3)
0.35
(10.9)
0.09
(4.4)
0.06
(6.3)
1.56
(17.9)
Moll us.

0.01
£<0.1)
0.38
(19.1)
0.09
(9.5)
0.87
(27.0)
0.0
0.0
0.34
(3.9)
Hemip.

0.03
(1.2)
0.0
0.01
(l.D
0.01
(0.3)
0.0
0.0
0.0
Modified Eesa
1 0.88
(7.0)
3 1.64
(26.1)
0.24
(1.9)
0.07
(1.1)
0.03
(0.2)
0.06
(1-0)
9.03
(72.3)
0.65
(10,3)
0.33
(2.6)
0.03
(0.4)
1.13
(9.0)
2.03
(32.4)
0.33
(2.7)
0.01
(0.2)
0.22
(1.7)
1.64
(26.1)
0.07
(0.6)
0.13
(2.1)

-------
         TABLE 12 (continued).  MEAN WET WEIGHTS5/ PER M2 AND AVERAGE PERCENTAGES OF THE SAMPLE-/ FOR

                            AQUATIC MACROINVERTEBRATES,-/ MARCH  1976 TO MARCH 1977
co
en

Station
5
6
7
Ephem.
0.34
(16.1)
0.99
(10.8)
0.56
(2.3)
Odon./
Zygop.
0.0
0.92
(10.1)
1.40
(5.8)
Plecop.
0.0
0.07
(0.8)
0.07
(0.3)
Inch.
0.60
(27.9)
3.89
(42.7)
16.85
(69.8)
Coleop.
0.04
(1.8)
0.23
(2.5)
0.16
(0.7)
Dipt.
1.05
(49.2)
2.77
(30.4)
4.47
(18.5)
Oli go.
0.05
(2.4)
0.04
(0.4)
0.14
(0.6)
Moll us.
0.0
0.0
0.28
(1.2)
Hemip.
0.04
(1.7)
0.16
(0.7)
0.0

      -In grams.

      -'In parentheses.

      ^Ephem = Ephemeroptera, Odon = Odonata, Zygop = Zygoptera, Plecop = Plecoptera, Trich =
        Trichoptera, Coleop = Coleoptera, Dipt = Diptera, Oligo = Oligochaeta, Mollus = Mollusca,
        Hemip = Hemiptera.

-------
          TABLE 13.  CHECKLIST AND DISTRIBUTION OF AQUATIC
            MACROINVERTEBRATES, MARCH 1976 TO MARCH 1977
Ephemeroptera
  Ephemerldae
    Ephovon album (Say)                            X         X
  Heptageniidae
    Heptagenia elegantuta (Eaton)        X    X    X    X    X    X    X
    Heptagenia sp. A                     X
    Stenonema termination (Walsh)         X                   X
    Rhithrogena sp.                                X              X
  Baetidae
    Baetis sp.A                         XXXXXXX
    Baetis sp. B                         XXXXXXX
    Centvoptilum sp.                     X    X    X    X    X    X
    Pseudocloeon sp.                     XXXXXXX
    Cdllibaetis sp.                      X
    Isonyahia siaca (Walsh)              X
  Leptophlebiidae
    Choroterpes albiannulata McDunn.     XXXXXXX
    Leptophlebia gravastella (Eaton)     XXXXXXX
    Traverella albertana (McDunnough)    X
  Ephemerallidae
    Ephemerelta inermis Eaton                      X         XX
  Caenidae
    Caenis sp.                           X                             X
  Tricorythidae
    Triaorythodee minutus Traver         XXXXXXX

Odonata
  Gomphidae
    Gamphus sp. A                        XXXXXXX
    Gomphus sp. B                                                 X
    Ophiogomphus sp.  (near sevevus)      X         X    X    X    X    X
  Libellulidae
    Sympetinm sp.                        X

Zygoptera
  Calopterygidae
    Retaerina amerioana (Fabricius)      X         X    X    X    X
  Coenagrionidae
    Amphagvion abbreviation (Selys)       X                        XX
    Argia fumipennis-violaaea  (Hagen)    XX         XXX
    Enallagma sp.                        X    X    X    X         XX
                                    36

-------
    TABLE 13 (continued).  CHECKLIST AND DISTRIBUTION OF AQUATIC
            MACRO-INVERTEBRATES, MARCH 1976 TO MARCH 1977
                                                        4
Plecoptera
  Nemouridae
    Brachyptera sp. (prob. fosketti)
    Nemoura sp.
    Capn-ia sp.
  Perlodidae
    Isoperla patricia Prison

Hemi ptera
  Corixidae
    Palmaaorixa gilleti Abbott
    Triahoeoviaca sp.
  Naucoridae
    Ambrysits mormon Montandon

Megaloptera
  Sialidae
    S-Lalis sp.

Trichoptera
  Psychomyiidae
    Polycentropus oinereus 1
  Hydropsychidae
    Hydropsyche bronta Ross
    Hydropsyche sp. A
    Hydropsyche sp. B
    Hydropsyahe sp. C
    Chetanatopsyohe spp.
  Hydroptilidae
    Hydroptila sp. A
    Hydroptila sp. B
    Mayatri-chia sp.
    Ithytriahia sp.
  Phryganeidae
    Ptilostomis sp.
  Limnephilidae
    Limnephilus sp.
    Onoaosmoecus sp.
    Anabolia  sp.
  Leptoceridae
    Oecetis avara  (Banks)
    Triaenodes sp.  (near  tarda)
    Neotopsyche sp. (Leptooella)
  Brachycentridae
    Broobyoentrus  sp.
X
X
X

X
X
X
X
X
X
X
                              X
                              X
X
X
X
X
X
X
X
X
X
X
X
X

X
X
X
X
X
X
X

X
X

X
X

X


X

X
X
X
X
X

X
X

X
X

X


X

X
X
X
X
X

X
X
X
X
X
X

X

X

X
X
X
X
X

X
X
X
X
X
X
X
X

X

X
X
X
X
X

X
X
X
X
X

X
X
X
X
X
X
X
X
X
X

X
X
X


X
X
X
X
X

X
X
                                    37

-------
    TABLE 13 (continued).  CHECKLIST AND DISTRIBUTION OF AQUATIC
            MACROINVERTEBRATES, MARCH 1976 TO MARCH 1977
Lepidoptera
  Pyralidae
    Cataolysta sp.

Coleoptera
  Dytiscidae
    Liodessus affinis (Say)
  Hydrophilidae
    Helophorus sp.
  Dryopidae
    Helichus striatue LeConte
    Heliehus suttu>alis LeConte
  Elmidae
    Stenelmie oregonensis
    Dubiraphia minima
    Microcylloepus pusillus (LeConte)
    Optioservus divergens (LeConte)

Diptera
  Tipulidae
    Tipula spp.
    Holorusia sp.
    Ormosia spp.
    Dicvanota spp.
    Lirmophila (Eloeophila) sp.
    Hexatoma (Erioeera) sp.
  Psychodidae
    Periaoma sp. A
    Perieoma sp. B
    Psychoda sp.
  Culicidae
    Chaoboms sp.
  Sltnullldae
    Simtlium spp.
  Chironomidae
  Heleidae
    Palpomyia spp.
    Dasyhelea spp.
  Stratiomyidae
  Tabanidae
    Chrysops spp.
    Tdbamis sp.
  Dolichopodldae
    Hydrophorus sp.
X
X
X
X
X
X
X
X
X
X
X
X
X
X
          X
          X
X
X
X
X
X
X
X
X
X
X
X
X
                    X
                    X
X
X

X
X
X
X
X

X
X
X
X
X
X
X
X
X
X
                    X
                    X
                    X
                    X
                    X
                              X
                              X
X
X

X
X
X

X
X
                                    38

-------
    TABLE 13 (continued).   CHECKLIST AND DISTRIBUTION OF AQUATIC
            MACROINVERTEBRATES, MARCH 1976 TO MARCH 1977
Diptera (continued)
  Empididae
    sp. A
    sp. B

Turbellaria

Nematomorpha

Oligochaeta

Hirudinea
  Glossiphoniidae

Amphipoda
  Talitridae
    Hyalella azteea (Saussure)

Acari

Basommatophora
  Physidae
    Physa spp.
  Lymnaeidae
    Lymnaea sp.
  Ancylidae
    Ferrissia sp.
  Planorbidae
    Gyraulus sp.

Heterodonta
  Sphaeriidae
    Sphaeriwn sp.
    Pisidium sp.

Eulamellibranchia
  Unionidae
 X     X     X    X    X    X    X
      X     X    X    X    X    X

           X    X    X    X

 X              X

 X     X     X    X    X    X    X
 X

 X
X    X    X    X    X

X         XXX
 X    X    XXX     X    X

      X              XX

                              X
 X    X    X    X    X    X     X
      XXX              X
Total taxa
60   42   50   50   60   59    60
                                    39

-------
           TABLE 14.  NUMBER OF OCCURRENCES^ AND AVERAGE NUMBERS PER OCCURRENCE^/ FOR AQUATIC
          MACROINVERTEBRATES COLLECTED IN INTRODUCED SUBSTRATE SAMPLES, MAY 1976 TO MARCH 1977


                                                              Sampling stations
Ephemeroptera
  Heptageniidae
    Heptagen'ia elegantula (Eaton)
    Eeptageni-a sp. A
    Stenonema terminatum (Walsh)
    Rhithrogena sp.
  Baetidae
    Baetie sp. A
    BaeHe sp. B
    Centroptilum sp.
    Pseudocloeon sp.
    Cal'l'ibaet'is sp.
    Isonyohia eiaaa (Walsh)
  Leptophlebiidae
    Choroterpee alb^annulata McDunn.
    Leptophlebia gvavastella (Eaton)
  Ephemerellidae
    JSphemevella inermia Eaton
  Caenldae
    Caenie sp.
  Tricorythidae
    Tricorythodea mlnutua Traver

Odonata
  Gomphldae
    Gomphus sp. A
    Gomphus sp. B
    Ophiogomphua sp. (near aeverus)
  Libellulidae
    Sympetrim sp.
 6 24
 7(11)
 1(4
 1(1)
 KD
 KD

13(46)
 3(12)
 2(1)

12(17)



 KD

 1(1)

 KD
           7(2)     13(5)     13(7)     15(15)    12(13)    13(6)
 5(19)
 9(6)

 3(2)
15(54)
 KD
 6(2)
 3(1)
                     KD
8
10
3
3
32)
4)
1)
17)
15(138)
 6(3)

 KD
 KD

 3(1)
             36)
             7)
           8(29)
          11(18)
           24)
           5(23)
15(114)
 5(4)
                                         KD
 7(1)

 2(1)
7(2)

4(2)
                                         1(3)
                              10
                               2
            24
             12)
15(118)   15(84)
 3(13)     9(9)
                                         1(2)
13(28)    12(27)    11(43)    12(45)
                                        10
                   15(31)

                    1(5)
                    6(3)
                    7(9)
                    10(5)

                    15(38)



                     KD

                     9(1)

-------
     TABLE  14 (continued).   NUMBER OF OCCURRENCES^/  AND AVERAGE NUMBERS PER OCCURRENCE^/ FOR AQUATIC
         MACROINVERTEBRATES COLLECTED IN INTRODUCED SUBSTRATE SAMPLES, MAY 1976 TO MARCH 1977

Sampling stations

Zygoptera
Calopterygidae
Hetaerina amerieana (Fabricius)
Coenagrionidae
Amphagrion abbreviatum (Selys)
1


5(3)

1(3)
Apgia fumipennis-violaeea (Hagen) 6(2)
Enallagma sp. 4(3)
Plecoptera
Nemouridae
Braehyp-teva sp. (prob. fosketti]
Perlodidae
Isoperla patricia Prison
Hemi ptera
Corixidae
Palmaoorixa gilleti Abbott
Tri.ahoaor-i.sxx, sp.
Naucoridae
Ambry sus mormon Montandon


—

—


__
2(1)

—
2


—

—
2(2)
KD


3(2)

—


__
—

10(12)
3


1(2)

—
1(1)


3(2)

2(1)


--
—

9(7)
4


KD

—
KD
2(2)


4(2)

—


KD


6(10)
5


2(1)

—
KD


KD

KD


2(4)
KD

9(9)
6


7(7)

4(1)
3(1)
4(5)


4(3)

4(2)


—
KD

7(9)
7


—

KD
5(2)


—

10(21)


--
—

7(1)
Megaloptera
  Sialidae
    SiaUa sp.                         —        —        --        —        -       1(1)       5(1)

-------
         TABLE 14 (continued).  NUMBER OF OCCURRENCES^/ AND AVERAGE NUMBERS PER OCCURRENCE^ FOR AQUATIC
              MACROINVERTEBRATES COLLECTED IN INTRODUCED SUBSTRATE SAMPLES, MAY 1976 TO MARCH 1977
PO

Trichoptera
Psychomyiidae
Polyaentropue oinereua ?
Hydropsychidae
Hydropsyche bronta Ross
Hydropeyche sp. A
Hy dropsy ahe sp. B
Hydropsyahe sp. C
Ch&imatopsyche spp.
Hydroptilidae
Hydroptila sp. A
HydropHla sp. B
Maya.trioh'ia sp.
Ithytriokia sp.
Phryganeidae
Ptilostomis sp.
Limnephilidae
Limnephilus sp.
Onoooemoeaus sp.
Anaboli-a sp.
Leptocerldae
Oecet-is avara (Banks)
Triaenodee sp. (near tavda)
Neatopeyche sp. (LeptoGella)
Brachycentridae
Braehyaentrue sp.

1


--

13 136)
9 20)
11 155)
7 11)
13 234)

4(24)
4(5)
KD
7(13)

1(3)

M1!
1(1)


9(14)
1(2)
8(8)

11(28)

2


—

11(5)
10 9)
14(123)
--
15(196)

3(7)
—
KD
3(4)

Sampling
stations
345


—

9(10) 11 ^
10(3) 13 :
12(52) 13 '
..


.

n 15(14)
18) 13(26)
13) 15(125)
.
15(62) 15(177) 15(609)


7(3) 4(6) 5(5)
1(
3(2) 1(
6(3) 6(^

1 KD
L
1 5(4)


6


KD

7 7)
9 3)
15 37)
—
15(390)

10 17)
5 18)
2 1)
3 5)

2(1) 1(1)

2(2)

1(4) -•

2(6)
1U) 315)
—

8(4)

1(1)

12(24)
—

.

10(5) 8(5) 9(6)
— _.
.
2(2) 2(2) 7(1)


6(211) 6(237) 6(130)

3(3
2(2
2(2

13 7)
14)
9 12)

6(29)

7


3(1)

13(5)
1(1)
15(197)
—
15(193)

14(58)
—
—
—

2(1)

3 2)
6 6
2 1)

9(1)
—
2(2)

14(22)

-------
         TABLE 14 (continued).  NUMBER OF OCCURRENCES^ AND AVERAGE NUMBERS  PER  OCCURRENCE^  FOR AQUATIC
              MACROINVERTEBRATES COLLECTED IN INTRODUCED SUBSTRATE SAMPLES,  MAY  1976  TO  MARCH 1977
CO

Sampling stations

Coleoptera
Dytiscidae
L-Lodessus affords (Say)
Hydrophilidae
Helophorus sp.
Dryopidae
Heli-chus stria.tus LeConte
Heliohus suturalis LeConte
Elmidae
Stenelmis oregonensis
Dubi'Vaphia minima
Mieroaylloepus pusillus
(LeConte)
Optioservus dtvergens (LeConte)
Diptera
Tipulidae
Tipula (Yamatotipula) spp.
Holorusia sp.
Ormos-La spp.
Diepanota spp.
L-imnophila. (Eloeophila) sp.
Hexatoma (Evioeera) sp .
Psychodidae
Perieoma sp. A
Periaoma sp. B
Simuliidae
Si-multum Spp.
Chironomidae
1


—

KD

2(2)
--

8(29)
11(11)

13(39)
—


--
—
__
KD
—
—

—
—

10(217)
13(165)
2


—

KD

5(4)
__

9(10)
8(3)

12(17)



--
—
_.
2(4)
--
KD

__
--

14(304)
15(63)
3


--

—

4(3)
--

11(10)
10(6)

13(27)
—


--
--
--
4(2)
--
--

—
--

15(390)
15(147)
4


—

--

4(3)
—

10(17)
12(22)

13(25)
--


--
—
--
3(5)
—
--

—
--

14(238)
15(104)
5


KD

—

7(15)
—

14(31)
13(11)

15(32)
KD


KD
—
--
8(11)
—
KD

—
—

15(246)
15(173)
6


—

—

7(14)
KD

13(50)
13(17)

11(21)



3(1)
—
—
3(2)
—
—

—
—

14(281)
15(228)
7


2(1)

—

7(6)
—

7(1)
11(8)

10(4)
10(5)


5(1)
2(1)
--
8(3)
KD
—

M1!
id)

9(9)
15(363)

-------
TABLE 14 (continued).  NUMBER OF OCCURRENCES^/ AND AVERAGE NUMBERS PER OCCURRENCE^/ FOR AQUATIC
     MACROINVERTEBRATES COLLECTED IN INTRODUCED SUBSTRATE SAMPLES, MAY 1976 TO MARCH 1977

Sampling stations

Diptera (continued)
Heleidae
Palpamyia spp.
Dasyhelea spp.
Strati omyidae
Tabanidae
Chryeops spp.
Dolichopodidae
Hydpaphorue sp.
Empididae
sp. A
sp. B
Turbellaria
Nematomorpha
Oligochaeta
Hirudinea
Glossiphoniidae
Malacostraca
Amphipoda
Talitridae
Hyalella azteca (Saussure)
Acari
1


1(2)
—
—

__

._

KD

--
KD
10(17)

—



5(2)
•»_
2


2(3)
—
—

—

--

6(2)
1(6)
—
—
8(5)

KD



	
««
3


3(2)
—
—

KD

—

8(5)
2(1)
2(4)
—
11(6)

—



3(4)
KD
4


3(1)
—
—

—

.-

5(3)
KD
5(4)
KD
12(8)

—



2(3)
__
5


6(2)
— / — s
1(1)
KD

-.

KD

7(7)
2(8)
6(19)
--
11(4)

--



3(1)
1(2)
6


11(5)
—
—

—

--

6(3)
3(2)
3(6)
—
14(20)

--



3(4)
2(1)
7


5(4)
1(44)
KD

—

—

8(4)
4(1)
—
—
13(31)

--



3(1)
2(1)

-------
        TABLE  14  (continued).   NUMBER  OF  OCCURRENCES^/  AND  AVERAGE  NUMBERS  PER OCCURRENCE^/  FOR AQUATIC
             MACROINVERTEBRATES COLLECTED IN  INTRODUCED SUBSTRATE SAMPLES,  MAY 1976 TO MARCH 1977

-------
TABLE 15.  NUMBER OF OCCURRENCES^ AND AVERAGE NUMBERS PER OCCURRENCE^/  FOR AQUATIC
 MACROINVERTEBRATES COLLECTED IN EKMAN DREDGE SAMPLES, MARCH 1976  TO  OCTOBER  1976


Ephemeroptera
Heptageniidae
Heptagenia eleganbula (Eaton)
Baetidae
Baetie sp. B
Centroptilum sp.
Leptophlebiidae
Chovotevpes albiannulata McDunn.
Caenidae
Caenie sp.
Tricorythidae
Tricorythodes minutus Traver
Odonata
Gomphidae
Gomphue sp. A
Ophiogomphus sp. (near sevevua]
Zygoptera
Coenagrionidae
Argia fumipennie-violacea (Hagen)
Endtlagma. sp.
Hemiptera
Corixidae
Palmaaorixa gilleti Abbott
Triahoaorixa sp.

1


--

— -
—

—

--

KD


KD
KD


—
--


KD
2(3)
Sampling stations
2345


1(1) - 1(2)

1(1) - KD
1(1) 	

2(6) 3(2) 2(2)

—

1(1) -- 3(8) 6(6)


2(1) 1(1) 3(1) 1(2)
—


KD 	
__ — __ —


-_
KD KD

6 7


—

__ —
—

1(3) 1(1)

2(2)

2(2)


4(1)
KD


—
KD


.
—

-------
         TABLE 15 (continued).  NUMBER OF OCCURRENCES^/ AND AVERAGE NUMBERS PER OCCURRENCE^/  FOR
        AQUATIC MACROINVERTEBRATES COLLECTED IN EKMAN DREDGE SAMPLES, MARCH 1976 TO OCTOBER  1976


                                                                 Sampling stations
Megaloptera
  Sialidae
    Sialis sp.

Trichoptera
  Psychomyiidae
    Polyoentropus ei-nereus 1               1(1)
  Hydropsychldae
    Hydropsyche bronta ROSS                1(1)
    Hydropsyahe sp. A
    Hydropsyahe sp. B                      2(1)     3(1)
    Cheumatopsyohe spp.                    2(3)     5(2)
  Hydroptilldae
    Hydroptila sp. A                       1(2)
  Limnephilidae
    Limnephilus sp.
  Leptoceridae
    Oeeetia avara (Banks)                  1(1)     1(1)
    Neetopsyohe sp. (Leptooella)
  Brachycentridae
    BYaahycentrue sp.

Coleoptera
  Elmidae
    Stenelmis ovegonensi-s                  1(1)     2(2)
    Dubiraphia minima                      8(21)    6(12)
    Mierooylleopus pus-Lllus  (LeConte)      4(2)     3(1)
         11
         3(2)
         4(2)
2(3)     3(3)
KD
8(15)
2(2)
3(3)
7(21)
3(1)
         KD
         2(1)
         52
         7(10)
         1(4)

         2(1)
         3(4)

         4(2)
5(3)
8(13)
3(2)
          KD
          2(12)

          KD

          KD
3(1)
7(2)
1(3)
                                     KD
         2(5)
         2(2)
                                     2(1)
          KD     K3)
7(7)

-------
         TABLE 15 (continued).   NUMBER OF OCCURRENCES^/ AND AVERAGE NUMBERS PER OCCURRENCE^/ FOR
        AQUATIC MACROINVERTEBRATES COLLECTED IN EKMAN DREDGE SAMPLES,  MARCH 1976 TO OCTOBER 1976

Sampling stations

Diptera
Tipulidae
Ormoeia spp.
Dievanota spp.
Psychodidae
Peyahoda sp.
Simuliidae
SirmHum spp.
Chironomidae
Heleidae
Palpomyia spp.
Tabanidae
Chvyaope spp.
Empididae
sp. B
Turbellaria
Oligochaeta
Hirudinea
Glossiphoniidae
1


__
—

—

2(4)
8(48)

5(3)

—

--
—
8(26)

— •
2


__
3(3)

—

3(2)
8(24)

4(2)

—

--
—
7(9)

--
3


__
—

1(1)

1(7)
8(61)

5(19)

KD

~
—
8(18)

--
4


1(D
1(3)

—

1(3)
8(42)

4(40)

—

KD
—
8(16)

KD
5


--
4(3)

--

4(2)
8(132)

6(4)

KD

— —
2(2)
8(6)

--
6


__
1(2)

—

KD
8(48)

3(31)

—

--
KD
7(4)

—
7


__
—

—

1(11)
7(134)

2(4)

—

--
—
7(40)

—
Malacostraca
  Amphipoda
    Talitridae
      Hyalella azteea (Saussure)
2(2)

-------
         TABLE 15 (continued).   NUMBER OF OCCURRENCES^/ AND AVERAGE NUMBERS PER OCCURRENCE-/ FOR
        AQUATIC MACROINVERTEBRATES COLLECTED IN EKMAN DREDGE SAMPLES, MARCH 1976 TO OCTOBER 1976


                                                                 Sampling stations
Basommatophora
  Physidae
    Physa spp.                             1(1)      ~       --      2(2)

Heterodonta
  Sphaeriidae
Sphaevi-wn sp.
P-isidium sp.
Eulamellibranchia
Unionidae
__
—

KD
2(2)
3(2)

--
1(2)
3(2)

--
2(1)
2(2)

__ --
1(1)
KD

— — — —

       indicates absence from samples.
  i
  In parentheses.

-------
tn
o
                  TABLE 16.  NUMBER OF OCCURRENCES^ AND AVERAGE NUMBERS PER OCCURRENCE^ FOR
            AQUATIC MACROINVERTEBRATES COLLECTED IN MODIFIED HESS SAMPLES,  MARCH 1976 TO MARCH 1977
Sampling stations

Ephemeroptera
Ephemeridae
Ephoron album (Say)
Heptageniidae
Eeptagenia elegantula (Eaton)
Baetidae
Baetis sp. A
Baetis sp. B
Peeudoaloeon sp.
Leptophlebiidae
ChoroterpeB dLb-icmnulata McDunn .
Leptophlebia gvavaetella (Eaton)
Traverella albertana (McDunnough)
Caenidae
Caenis sp.
Tricorythldae
Trieorythodes minutus Traver
1


—

1(4)

2(42)
9(8)
3(8)

11(42)
1(2)
KD

—

7(6)
3


2(2)

KD

2(5)
2(1)
2(2)

5(270)
KD

—

3(9)
5


KD

--

2 3)
5 7)
3 1)

11(25)

__

4(3)
6


__

3(1)

2(11)
12(39)
4(13)

12(45)
2(4)

__

11(28)
7


_ _

3(3)

• Ml
12(35)
KD

—

1(3)
™ \ ^ *
10(21)
       Odonata
         Gomphidae
          Ophiogomphus sp.
(near severus)
2(1)
KD
       Zygoptera
        Calopterygidae
          Hetaevi.no. americana  (Fabricius)
        Coenagrionidae
          Enallagma sp.
7(1)
                                                           KD
5(2)
                                                                       1(2)

-------
     TABLE 16 (continued).  NUMBER OF OCCURRENCES^/ AND AVERAGE NUMBERS PER OCCURRENCE^/ FOR
     AQUATIC MACROINVERTEBRATES COLLECTED IN MODIFIED HESS SAMPLES, MARCH 1976 TO MARCH 1977


                                                              Sampling stations
Plecoptera
  Nemouridae
    Nemoura sp.
    Braohyptera sp. (prob. fosketti)
    Capnia sp.
  Perlodidae
    Isoperla patx>iaia Prison

Hemi ptera
  Corixidae
    Palmaoorixa gilleti Abbott
  Naucoridae
    Ambryeus mormon Montandon

Megaloptera
  Sialidae
    S-ialis sp.

Trichoptera
  Hydropsychidae
    Hydropsyche bronta Ross
    Hydropsyche sp. A
    Hydropsyohe sp. B
    Hydropsyohe sp. C
    Cheimatopsyehe spp.
  Hydroptilidae
    Hydroptila sp. A
    Hydroptila sp. B
    Mayatriahia sp.
 1(2)
 2(1)
12(71)
 3(10)
11(105)
 2(6)
12(84)

 6(4)
 2(8)
 2(1)
2(1)
2(2)
43
2(2)
3(8)

6(25)

3(2)
2(4)
            4(4)
            2(1)
            7(4)

           10(34)
            1(1
            1(1
            KD
3(3)


5(1)



KD

3(3)
            6(5)
            3(2)
           12(36)

           12(149)

            9(24)
            3(1)
            1(15)
                        KD

                        1(1)

                        8(4)
            1(3)



           10(3)

           12(162)

           12(231)

           11(32)
            1(11)

-------
            TABLE 16 (continued).  NUMBER OF OCCURRENCES^ AND AVERAGE NUMBERS PER OCCURRENCE^/ FOR
            AQUATIC MACROINVERTEBRATES COLLECTED IN MODIFIED HESS SAMPLES, MARCH 1976 TO MARCH 1977
                                                                     Sampling stations
en
tva
       Trichoptera (continued)
         Limnephilidae
           Limneplvilus sp.
           Onooosmoeoua sp.
         Leptocerldae
           Oeoetie avora (Banks)
           Neetopeyche sp.  (Leptoeella)
         Brachycentridae
                         sp.
Lepidoptera
  Pyralidae
    Cataelysta sp.

Coleoptera
  Dryopidae
    Helichue striatus LeConte
  Elmldae
    Stenelmis ovegonensis
    Dubtraphia minima
    Miaroaylloepus pusillus (LeConte)
    Optioeervus divevgens (LeConte)

Diptera
  Tipulidae
    Tipula (Yamatotipula) spp.
    Holorueia sp.
    Ormos-ia spp.
    Di-Qvanota spp.
    Limnophila (Eloeophila) sp.
                                            5(2)
                                            4(30)
                                                   5(4)
                                                   1(2)

                                                   8(15)
                                                   8(3)
                                                  11(64)
                                                   1(1)
                                                   5(4)
2(1
1(1
5(5)
2(3)
3(5)
4(4)
2(4)


4(7)
              9)
              4\
              13)
1(2)

7(7)
                                                                                 Kl)
4(6
1(1

3(8)
           12(33)
           10(4)
            8(31)
            4(3)
KD


7(6)
                                    1(2)

                                    1(2)


                                    7(4)
            KD

            8(2)
           10(4)
           12(8)
           12(14)
                                    4(4)

                                    3(3
                                   11(4
                                    2(2

-------
     TABLE 16 (continued).   NUMBER OF OCCURRENCES5/ AND AVERAGE NUMBERS PER OCCURRENCE^/ FOR
     AQUATIC  MACROINVERTEBRATES COLLECTED IN MODIFIED HESS SAMPLES, MARCH 1976 TO MARCH 1977

Sampling stations

Diptera (continued)
Culicidae
Chaoborus sp.
Simuliidae
Sixmlivm spp.
Chironomidae
Heleidae
Palpomyia spp.
Tabanidae
Chryaops spp.
Tdbonus sp.
Empididae
sp. A
sp. B
Turbellaria
Nematomorpha
Ollgochaeta
Amphipoda
Talitridae
Hyalella azteea (Saussure)
Acari
1


--

12(51)
12(150)

4(2)

—
—

3(1)

—
KD
11(35)


—
KD
3


KD

4(225)
5(66)

KD

KD
—

3(2)
--
2(4)
—
4(6)


—
—
5


—

11(63)
12(44)

7(2)

—
--

2(4)
1(4)
3(4)
__
9(16)


—
--
6


—

12(132)
12(253)

8(13)

—
--

5(9)
2(2)
6(6)
—
10(13)


KD
2(2)
7


—

8(6)
12(108)

6(4)

5(1)
i \
KD

7(2)
3(2)
—
—
12(26)


2(1)
2(1)
Basommatophora
  Physidae
    Physa spp.
2(1)

-------
            TABLE 16 (continued).  NUMBER OF OCCURRENCES5/ AND AVERAGE NUMBERS PER OCCURRENCE^/ FOR
            AQUATIC MACROINVERTEBRATES COLLECTED IN MODIFIED HESS SAMPLES, MARCH 1976 TO MARCH 1977


                                                                     Sampling stations
en
Basommatophora (continued)
  Ancylidae
    Ferriesia sp.

Heterodonta
  Sphaeriidae
    Sphaerium sp.
    Pieidium sp.
                                                   3(2)
1(10)
KD
                                    1(2)
4(3)
1(5)
       a/
         Dash indicates absence from samples.
        t
         In parentheses.

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    30



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    40




    30



    20



     10
   200
    100
          — Sttn»/mis oregonensis

        	Dubiraphia minima
          — BatI'is sp. B

          -- Boetis sp. A
        	Hydropsychg sp. B

        	Choroterpes sp.
                                              — Microcylloepus pusillus

                                            	Htlichus  striatus
                                               • Tricorythodes mint/fas

                                                Heptagenia  eltgantolo
                                                • Brachycentrus sp.

                                                • Hydropsyche  bronta
                               567123

                                 SAMPLING  STATIONS
 Figure  9.  Average  numbers of  selected taxa per introduced substrate
                        sample, May 1976  to March  1977.
                                        55

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    20
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     10
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    400
    200
          -Isoperlo patricia
         - - Otcatis avara
              V-**'
          -Pstudocloeon  sp.
        	Leptophlebia gravas tafia
           -Cheumatopsyche spp
                                              •Hydropsyche sp. A

                                              -Hydroptilo sp. A
54
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                                             —Ambrysus mormon

                                             — Nectopsycha spp.
                                              •Simulium spp.
                               567    123


                                SAMPLING  STATIONS
 Figure  9 (continued).   Average numbers of  selected  taxa  per introduced
                  substrate sample, May 1976  to March  1977.
                                        56

-------
upstream.  Hydropsyehe sp. A, Cheumatopsyahe spp., and Pseudooloeon sp. were
most abundant in introduced substrate samples at Station 5.

     Restricted distribution patterns were evident for certain taxa (Table
13).  Optioservus divergens was common only at Station 7 and absent from
Stations 1 through 4.  Ephoron album was collected rarely and only at Stations
3 and 5.  Caen-is spp. was common at Station 7, rare at Station 1, and absent
from intervening stations.  Traverella albertana was collected only once at
Station 1 although it was found to be abundant in the Yellowstone River in
this vicinity (Newell, 1976).  Sialis sp., collected in silted substrata at
Stations 6 and 7, was absent from Stations 1 through 5.  Certain Tipulidae
(e.g., Tipula spp., Holorusia sp., and Limnophila sp.) were collected only at
Stations 5, 6, and 7.  Perieoma spp. were collected only at Station 7.
Plecoptera were rare; however, nymphs of a winter stonefly, Brachyptera spp.,
were present at Stations 1 through 6 and possibly correspond to adult
Braohyptera fosketti collected in March 1976.  Isoperla patricia was present
in greatest numbers at Station 7 and was absent from Stations 1, 2, and 4.
Certain taxa (e.g., Isonyahia siaaa, Hydropsyahe sp. C, Cataelysta sp., and
Sympetrum sp.) were collected only from the unique habitat present at Station
1.

     A temporal pattern of emergence appeared to be present for certain taxa.
Population cycles for Hydropsyehe sp. B and Dttbiraphia minima reached numeri-
cal peaks during different months depending on the station (altitude) (Figures
10 and 11). In contrast, numbers of Choroterpes albiannulata appeared to peak
bimodally and simultaneously at all stations (Figure 12).

     Results from modified Hess samples (Table 16) showed that individual
taxa were often numerically least abundant at Station 5, a distinct contrast
with data from introduced substrate samples.  Total numbers for individual
taxa were generally highest at Stations 1,6, and 7.  The mid-Rosebud
(Stations 2, 3, 4, and 5) could not be sampled adequately enough to give
species distribution for these stations.

DIVERSITY AND REDUNDANCY

     A total of 92 taxa were collected in Rosebud Creek.  Stations 1, 5, 6,
and 7 had similar numbers of species although the composition varied.  Fewer
taxa were found at Stations 2, 3, and 4 (Figure 13).  Average species
diversity and redundancy per sample is presented in Table 17.

Introduced Substrate Samples

     The average number of taxa per sample (Table 7) is highest at Stations
5, 6, and 7 corresponding with trends for average numbers and biomass.

Ekman Dredge Samples

     The average number of taxa in pools was highest at Stations 4 and 5 and
lowest at Stations 6 and 7, a condition contrasting with results from intro-
duced substrate and modified Hess samples.  Station 3 was also low for
average number of taxa per sample.


                                      57

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   400
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             — STATION  I
             — STATION 5
             - STATION 7
       \
         \
           *

           \
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              *

               \
                                                                \
           M
      Figure  10.   Seasonal variations in mean total numbers of
       Hydropsyche sp. B per introduced substrate sample at
          Stations 1, 5, and 7, May 1976 to November 1976.
                                  58

-------
                                       	 STATION I
                                       	STATIONS
                                       	 STATION 7
Figure 11.  Seasonal variations in mean total numbers of
  Dubiraphia minima per introduced substrate sample at
    Stations 1, 5, and 7, May 1976 to November 1976.
                             59

-------
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                                   STATION 5
                                   STATION 6
                    \
        \


 ,/A  \
' I      *   •
                       A

                   MONTH
                                        I X
                                        ( \
    Figure 12.  Seasonal  variations in mean total  numbers of
   Choroterpes albicmnulata  per introduced substrate-sample at
        Stations 1, 5,  and 6, May 1976 to November 1976.
                                60

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<  60

X
  UJ
     30
00
^ cc
  o
     15
                                                                   TOTAL



                                                                   INTRODUCED

                                                                   SUBSTRATE
                                                                   MODIFIED

                                                                   HESS
                             345


                          SAMPLING  STATIONS
                                                                 EKMAN  DREDGE
   Figure 13.  Total taxa per  station  and taxa collected by each  of three

                 sampling methods,  March 1976 to March 1977.
                                      61

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    TABLE 17.   MEAN MACROINVERTEBRATE  DIVERSITIES AND REDUNDANCY
                PER SAMPLE,  MARCH  1976 TO MARCH 1977
              Shannon's        Margalef       Simpson
Station        Index           Index           Index        Redundancy

                       Introduced substrates

   1            2.89            2.95            0.21           0.36
   2            2.20            2.37            0.36           0.48
   3            2.30            2.70            0.32           0.47
   4            2.42            2.72            0.31           0.46
   5            2.40            2.95            0.33           0.49
   6            2.61            3.40            0.30           0.46
   7            2.55            3.22            0.25           0.46
                           Efonan  dredge

   I            1.66             1.28           0.42            0.47
   2            1.81             1.64           0.38            0.55
   3            1.73             1.11           0.37            0.36
   4            2.11             1.85           0.31            0.42
   5            1.92             2.05           0.41            0.49
   6            1.30             1.25           0.53            0.66
   7            1.11             0.87           0.58            0.58
                           Modified Hess

   1            2.48            2.36           0.28           0.41
   3            1.90            2.26           0.38           0.57
   5            1.99            1.91           0.39           0.48
   6            2.82            2.79           0.21           0.35
   7            2.43            2.84           0.26           0.44
                                  62

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Modified Hess Samples

     Average number of taxa per sample was  highest at Stations  1,  6,  and  7
(Table 7).  Lowest numbers of taxa were found at Station  5;  Station 3 was
also low in comparison to Stations 6 and 7.
                                      63

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                                SECTION VIII

                                 DISCUSSION

     Basic information concerning the composition of the macroinvertebrate
community of Rosebud Creek in terms of distribution, diversity, and abundance
was gathered during this study.   Variation of these parameters among sampling
stations was considered with respect to potential chemical effluents from
coal mining and combustion and with respect to the physical-chemical nature
of the Rosebud Creek system.

WATER CHEMISTRY:  METALS

     Concentrations of selected metals in Rosebud Creek (Table 4) are gener-
ally below criterion levels recommended by the U.S. Environmental Protection
Agency (1976).  Average copper and zinc concentrations are highest at Sta-
tions 3 and 4 but probably do not present a threat to the benthic fauna.
Present levels are far less than the TL50 values (14 day) presented by Nehring
(1976) for Pteronarcys caHfomioa or Ephemerella gvandis or the 48-hr TLm
determined for copper on Ephemerella eubvaria (Warnick and Bell, 1969).

     Average total mercury exceeded the criterion concentrations of 0.05 yg/1
total mercury recommended for freshwater aquatic life and wildlife by the
Environmental Protection Agency (1976).  Aquatic insects vary widely in their
sensitivities to mercury but present concentrations in Rosebud Creek (Table
4) are less than the 2.0 mg/1 and 33.5 mg/1 toxic concentrations (96-hr
TLm) of mercury (HgCl2) for Ephemerella subvaria and Aovaneuria lyaoyiae
given by Vlarnick and Bell (1969).  In this study it was not possible to
attribute low average numbers, standing crop, and taxa (introduced substrates)
at Stations 2, 3, and 4 to the reported mercury concentrations.  Follow up
chemical and biological studies are warranted.

PHYSICAL CONDITIONS

     Physical conditions of Rosebud Creek are typical of eastern Montana
transition prairie streams.  Notable conditions include extreme turbidity,
high suspended load, and warm water temperatures all of which increase pro-
gressively downstream.  These factors, and indirect effects from low stream
gradient, influence the abundance and distribution of the benthic
macroinvertebrate fauna.

Turbidity

     Rosebud Creek is extremely turbid even during low flows, particularly at
Stations 1 and 2  (Tables 2 and 4).  This condition results in a decrease


                                      64

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in euphotic zone depth due to light extinction and a consequential  reduction
in primary production (Bartsch, 1959).   Most temperate streams are  hetero-
trophic, that is, production from photosynthesis is exceeded by community
respiration and allochthonous material  is an important source of energy
(Boling et al., 1975).  The turbid state of Rosebud Creek results in alloch-
thonous detritus becoming more significant as an energy source and  the
benthic community is composed of many organisms utilizing primarily detrital
food sources.  For example, Hydropsychidae and Simuliidae, both common in
Rosebud Creek, are omnivorous collectors filtering fine particles from the
water column (Ross, 1944).  Leptophlebiidae, the dominant mayfly family
encountered, are also omnivores and detritivores (Berner, 1959) and the
larvae and adults of Elmidae ingest decaying wood and encrusting algae
(Brown, 1972).

Temperature

     Extreme summer water temperatures occur in Rosebud Creek and influence
the distribution of aquatic macroinvertebrates.  Dodds and Hisaw (1925) con-
cluded temperature to be the main climatic cause for altitudinal zonation of
aquatic organisms.  Altitudinal distribution of Plecoptera is due to the
maximum water temperature the nymphs can tolerate (Knight and Gaufin, 1966).
Of four taxa of Plecoptera collected from Rosebud Creek, two were collected
only at the uppermost location (Station 7) and Isoperla patriaia was common
only at Stations 6 and 7.  This distribution is probably due to cooler summer
water temperatures near the headwaters.  Braohyptera sp., a stonefly col-
lected at Stations 1 through 6, undergoes rapid development during fall and
winter and emerges during late winter or early spring.  Naiads of Brachyptera
undergo summer diapause to escape warm water temperatures at that time
(Harper and Hynes, 1970).  In addition, water temperature is a factor in
timing the emergence of aquatic insects (Nebeker, 1971).  The apparent
temporal patterns of emergence in Hydropsyche sp. B and Dubiraphia minima
(Figures 10 and 11) may be due to cooler water temperatures at upstream
stations.

Substrate, Current Velocity, and Gradient

     A complex interaction among stream gradient, discharge, suspended load,
and current velocity exists which influences the quality of the benthic
habitat.  The longitudinal profile or gradient of most streams is typically
concave, decreasing downstream (Mackin, 1948) and is usually accompanied by a
downstream reduction in substrate size  (Leopold and Maddock, 1953).  Head-
waters typically have boulder or gravel substrates and steep slopes; down-
stream the size of bed material is smaller and sand may be common.  Near the
mouth silt or clay may predominate.  This generalized description of stream
substrate applies to conditions found in Rosebud Creek.  Near the headwaters
gravel and cobble substrates are common; sand and gravel bed material are
more abundant downstream as the slope decreases.  At Station 2, long, deep
reaches with flocculent clay or silt bottoms are prevalent.  At Station 1 the
slope increases as Rosebud Creek approaches the Yellowstone River and there
is a corresponding increase in pool-riffle periodicity with rubble and boulder
substratum in the riffles.  Riffles are uncommon at Stations 2, 3, and 4 due
to the low stream gradient.

                                      65

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     Substrate conditions (I.e.,  size and degree of sedimentation)  have been
termed the most important single  factor influencing macroinvertebrate habitat
quality (Pennak, 1971).  Large substrates such as rubble and cobble support
larger invertebrate populations than sand and gravel (Pennak and Van Gerpen,
1947).  Riffles composed of stable substrates are the most productive type of
bottom in streams (Patrick, 1949).  Consequently, a longitudinal decrease in
substrate size and frequency of riffles as occurs in Rosebud Creek  will
result in lower macroinvertebrate production and standing crop downstream.

     Two consequences of reduced  gradient include diminished overall current
velocity (Reid, 1961), and lowered sediment carrying capacity which results
in deposition of part of the suspended load (Morisawa, 1968).  The  ultimate
factor influencing sediment transport relates to the supplied load; i.e.,
input from erosion.  If supplied  load exceeds carrying capacity then deposi-
tion and/or change in stream morphology will occur.  In Rosebud Creek the
combined effect of the increasing sediment load and decreasing gradient in a
downstream direction results in deposition of sediments on the substratum
(Stations 2 through 5).

     Deposition of inorganic sediment can turn otherwise suitable substrate
into poor macroinvertebrate habitat (Cordone and Kelley, 1961).  Stable
substrates are covered and, more  importantly, interstitial spaces in the
substrate, where much of the secondary production occurs, are filled.  Many
aquatic organisms seek refuge from swift current and the abrasive effect of
bed load by inhabiting spaces between or under rocks.  Further, much of the
secondary production in streams occurs deep within the substratum.   Coleman
and Hynes (1970) found that 83% of the benthic community lived below 5 cm in
the substrate.  Poole and Stewart (1976) reported that 33.6% of the total
number of organisms were deeper than 10 cm in the bed of a Texas river.  It
is evident that occlusion of interstitial spaces with inorganic sediment will
eliminate habitat and decrease diversity and secondary production.

     Conversely, deposition of organic sediments at slow current velocities
may increase benthic production (Ruttner, 1952).  At slow current speeds
gravel and sand substrates become more stable; this, in combination with
enrichment from organic sediments, creates an environment suitable  for many
invertebrates.  In Rosebud Creek, the common long reaches with slow current
velocities of 0.6 m/sec and less, support productive bottom faunas, e.g.,
Oligochaeta and Chironomidae, dependent on allochthonous detritus.

     Sedimentation and a decrease in overall substrate size probably con-
tributed to the lower benthic diversity and population numbers at Stations 2,
3, and 4 due to occlusion of interstitial spaces and decrease in habitat
variety.  Lower diversities, in comparison to other sampling sites, were
found at Stations 2, 3, and 4 with introduced substrate samplers, at Stations
3 and 5 with modified Water's round samplers, and at Station 3 using an Ekman
dredge.  Also, introduced substrates showed low numbers at Stations 2, 3, and
4 which may be due to low populations of benthic macroinvertebrates for
sampler colonization in these sections of Rosebud Creek.

     Substrate conditions at the point of sampling influenced results from
modified Hess and Ekman dredge samplers.  The infrequence of riffles in

                                      66

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Rosebud Creek at many stations limited the choice of sampling location.   For
example, the existing riffle at Station 5 consisted of unstable gravel which
resulted in low standing crop, numbers, and diversity from modified Hess
samples taken at this station.  Conversely, introduced substrates showed
Station 5 to have a high population and diversity relative to other sampling
sites.

     Low numbers, standing crop, and diversity encountered in Ekman dredge
samples at Station 6 can likewise be attributed to the sand substratum common
in pools.  Sand supports notoriously small populations of benthic inverte-
brates due to its unstable, grinding nature and lack of available food.

Current Velocity

     Many stream-dwelling aquatic organisms are morphologically or behavior-
ally adapted to select habitats on the basis of current velocity.  In streams,
rapid flowing portions generally support higher numbers of benthic inverte-
brates than lentic stretches with the same substrate.  Long, slow stretches
that are common in Rosebud Creek had reduced numbers and fewer species.
Hydropychidae, which depend on rapid current for proper functioning of their
nets (Ross, 1944), were encountered in lower numbers at Stations 2, 3, and 4
where current velocity is generally slow.  Elmidae, known to inhabit rapidly
flowing portions of streams (Brown, 1972), were found in lower numbers at
Stations 2, 3, and 4..  Choroterpes alb-umnulata and Ambrysus mormon, both
abundant at Stations 2, 3, and 4, are tolerant of slow flowing situations
(Edmunds et a!., 1976; Roemhild, 1976).  Current velocity may have directly
influenced the distribution of these and other taxa (Figure 9) but probably
had a more profound effect by influencing substrate composition.

     The tendency for various taxa to be low in abundance at Stations 2,  3,
and 4 (introduced substrates) was influenced by any one or a combination  of
the physical conditions imposed by extreme turbidity, sediment deposition,
small substrate size, slow current velocity, and high temperature in Rosebud
Creek.  Certain of these conditions were most extreme at Station 2 (low
gradient, silted substratum, and slow current velocity) and imposed unfavor-
able conditions for many macroinvertebrates.  Conversely, upstream sections,
because of increased gradient, and decreased turbidity and temperature
supported more productive macroinvertebrate populations.

MACROINVERTEBRATE ABUNDANCE AND COMPOSITION

     The benthic fauna of Rosebud Creek is similar in composition to that
found in Sarpy Creek, approximately 40 km west (Clancy, 1977).  The lower
Yellowstone River and the Powder River support faunas similar to Rosebud
Creek and also decrease in diversity downstream (Newell, 1976; Rehwinkel
et al.. 1976).

     Despite an extreme environment, Rosebud Creek supports a surprisingly
abundant and diverse fauna that is adapted to the prevailing conditions.   In
terms of numbers of benthic invertebrates, it could be described as a rich
stream.  Very little quantitative data exist on comparable streams in
eastern Montana; however, population estimates of 4993 and 6007 invertebrates

                                      67

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per m2 from pools and riffles, respectively, in Rosebud Creek were greater
than the average 2809 invertebrates per m2 for the middle Yellowstone River
(Thurston et al.. 1975).  Data from the West Fork of the Gallatin River, a
typical mountain stream similar in size to Rosebud Creek, averaged 1877
invertebrates per m2 during 1970-1971 (unpublished data).

     Among important conditions conducive to high population numbers of ben-
thic macroinvertebrates in Rosebud Creek was the intact riparian vegetation
which kept the stream within its banks; this prevented extreme erosion,
scouring, and siltation.  This vegetation was also an important energy source
for Rosebud Creek where primary production was limited by turbidity.

     Many of the commonly encountered macroinvertebrates of Rosebud Creek
were adapted to live in turbid, silt-laden, or slow-flowing habitats.
Cheumatopsyche spp. have been reported to be tolerant of a wide range of
ecological conditions; Chewnatopsyche las-la was commonly found in heavily
silted streams.  Triaorythodes minutus, Caenis sp., Chovotevpes albi&nnulata,
Leptophlebia gravastella, and Isonyahia siaea occur in silted or slow-flowing
streams (Edmunds et al., 1976).  Microaylloepus pusillus is tolerant of
siltation and turbidity (Brown, 1972).  Isoperla patricia inhabits prairie
streams that originate in the mountains (Ricker, 1946).   Dubiraphia minima,
collected abundantly from pools and riffles, can be classified as tolerant of
siltation and slow current velocity.  Many taxa that are numerically abundant
in the mid-Rosebud, e.g., Simulium spp., Choroterpes albiannulata, Sphaerium
spp., and Ambrysus mormon* have wide tolerances to ecological conditions.  As
a generalization, aquatic invertebrates present in large numbers in the
prairie portion of Rosebud Creek could be classed as tolerant of turbid,
silty conditions.

SAMPLING CONSIDERATIONS

     To describe accurately the aquatic fauna, it is necessary to sample as
many habitat types and take as many samples as possible.  Benthic organisms
select habitat on the basis of various physical and chemical conditions,
i.e., substrate, current velocity, depth, dissolved oxygen, temperature, etc.
Three habitat types including riffles, pools, and long,  gravel-bottom runs
were sampled semi-quantitatively during this study.  Analysis of results
indicated that species composition varied with habitat and sampling device.
Modified Hess and Ekman dredge samplers collected 62 and 46% of the total
taxa found, respectively.  Introduced substrates were most efficient in
collection of numbers and taxa; 89% of the total taxa collected including 22
not collected by other methods were found in introduced substrate samples.
Certain organisms, e.g., Ephoron album and Cataelyeta sp., were collected in
modified Hess samples but were absent from other methods.  Chironomidae and
Oligochaeta composed the majority of the pool fauna; Trichoptera, Diptera,
and Ephemeroptera predominated in riffles and in introduced substrate
samples.

     The long, hard-bottom slow reaches that are the most common habitat in
Rosebud Creek could not be effectively sampled using an Ekman dredge or Hess
sampler.  However, introduced substrate in baskets was an efficient method
for sampling these habitats.  Their use permitted standardization of substrate

                                      68

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kind and size and enabled selection of sampling sites which had comparable
water depth and current velocity.  This made quantitative comparisons between
stations more valid than with conventional grab type samplers.  In addition,
introduced substrates were proficient in collecting macroinvertebrate taxa.
The samplers offered clean unsedimented substrates exposed to the current
which were attractive to many organisms including Hydropsychidae, Simuliidae,
and Baetidae, and because they rested flat on the substrate, a degree of
sedimentation occurred near the basket bottom and invertebrates that dwell 1n
fine substrates (e.g., Oligochaeta, Odonata, Sphaeriidae, and Chironomidae)
also colonized the samplers.  The number of species found in introduced
substrate samples and the distribution of these species among sampling sta-
tions was a relatively accurate population parameter.  However, introduced
substrates are selectively colonized by various insects including mayflies,
caddisflies, and beetles (Grossman and Cairns, 1974).  Consequently, results
did not represent the existing standing crop, population numbers, or dis-
tribution of individuals among the species.  Accurate measurement of these
parameters would necessitate collection and analysis of cores of the existing
substrate at each station.

     Year-round sampling is necessary to describe macroinvertebrate distri-
bution and abundance.  Benthic organisms vary in population numbers from week
to week depending on details of life histories (Pennak and Van Gerpen, 1947).
In Rosebud Creek Bvaohypteva spp. are present in winter and spring but not in
summer samples.  Various taxa, i.e., SimuHum spp. and Chorotevpee
albiannulata, exhibit tremendous peaks in population numbers and form a sub-
stantial portion of the standing crop at that time.  Their numbers may be an
insignificant portion of the total aquatic population at other phases of the
life cycle (egg and adult).  Life histories also influence accuracy of macro-
invertebrate identification.  Early instars are often difficult to identify
and collection of later stages is needed for accurate identification in many
cases.

     Longitudinal variations in the benthic macroinvertebrate fauna were due
to influences from the unique physical-chemical nature of Rosebud Creek and
to influences from domestic and agricultural practices.  Variations in the
benthic community during the study could not be attributed to effluents from
coal mining or combustion.
                                      69

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                                   TECHNICAL REPORT DATA
                            (Please read Instructions on the reverse before completing)
1. REPORT NO.
  EPA-600/3-78-099
                              2.
                                                           3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
  Environmental Effects of  Western Coal Combustion
  Part II - The Aquatic Macroinvertebrates of Rosebud
  Creek, Montana                               	
             5. REPORT DATE
               November 1978  issuing  date
             6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
                                                           8. PERFORMING ORGANIZATION REPORT NO.
  Steven F. Baril, Robert  J.  Luedtke, and George  R.
                                            Roemhild
9. PERFORMING ORGANIZATION NAME AND ADDRESS


  Montana State University
  Bozeman, Montana  59717
                                                            10. PROGRAM ELEMENT NO.
             11. CONTRACT/GRANT NO.

                R803950
12. SPONSORING AGENCY NAME AND ADDRESS
  Environmental Research Laboratory—Duluth, MN
  Office of Research and Development
  U.S.  Environmental Protection Aqencv
  Duluth, Minnesota  55804
             13. TYPE OF REPORT AND PERIOD COVERED
                Final
             14. SPONSORING AGENCY CODE
                EPA/600/03
15. SUPPLEMENTARY NOTES
16. ABSTRACT
      The aquatic macroinvertebrates of Rosebud Creek,  Montana, were sampled  between
 February 1976 and March  1977  to provide data on their  abundance, distribution,  and
 diversity.   The sampling program was initiated during,the first year of operation  of
 the  coal-fired power plants located at Col strip, Montana.   The purpose of the  study was
 to determine if any immediate impacts of the power plant  operation on the macroinverte-
 brate communities of Rosebud  Creek could be detected and  to provide data for comparisons
 with future studies.

      Rosebud Creek supported  a  diverse bottom fauna with  high population numbers com-
 posed of species adapted to the turbid, silty conditions  which are common in the
 prairie streams of eastern Montana.  Intact riparian vegetation appeared to  be
 important in maintaining stream bank stability and provided an essential food  source.

      It was concluded that faunal  variation among sampling stations during the  study
 period was  attributable to physical factors including  turbidity, water temperature,
 current velocity, and substrate,  and not to potential  impacts from coal mining  and
 combustion.
17.
                                KEY WORDS AND DOCUMENT ANALYSIS
                  DESCRIPTORS
                                              b.lDENTIFIERS/OPEN ENDED TERMS  C.  COS AT I Field/Group
 Biological surveys
Energy development
Macro i nvertebra tes
Effects pollution
Mining effects
Pollution survey
Benthic survey
                                                                               57H
                                                                               68D
18. DISTRIBUTION STATEMENT


    RELEASE TO  PUBLIC
19. SECURITY CLASS (ThisReport)
     UNCLASSIFIED
21. NO. OF PAGES
     85
                                              20. SECURITY CLASS (Thispage)

                                                   UNCLASSIFIED
                                                                         22. PRICE
EPA Form 2220-1 (Rev. 4-77)   PREVIOUS EDITION is OBSOLETE
                                            75
                       4 U.S. GOVEMIMEKTIWrniK: OFFICE: 1978— 657-060/1526

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