Biological integrity of Big Dry Creek and Little Dry Creek Garfield County, Montana based on the composition and structure of the Benthic algae community

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MONTANA STATE LIBRARY

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3 0864 1001 6047 5

BIOLOGICAL INTEGRITY
OF BIG DRY CREEK AND LITTLE DRY CREEK

GARFIELD COUNTY, MONTANA

BASED ON THE COMPOSITION AND STRUCTURE

OF THE BENTHIC ALGAE COMMUNITY

Prepared for:

Garfield County Conservation District
400 Main Street
P.O. Box 3 69
Jordan, Montana 59337-0369

Prepared by:

Loren L. Bahls, Ph.D.
Hannaea
1032 Twelfth Avenue
Helena, Montana 59601

TATE DOCUWEMTS COLLECTION

nCT15 2002

MONTANA STATE LIBRARY
1515 E. 6th AVE.

'-•"LENA, MONTANA 59o20

-An

November 14, 2000

#

CONTENTS

Page

SUMMARY i

INTRODUCTION 1

PROJECT AREA AND SAMPLING SITES 3

METHODS 3

Quality Assurance 6

RESULTS AITO DISCUSSION 6

Field and Scunple Notes 7

Non-Diatom Algae 7

Big Diy Creek 7

Little Dry Creek 8

Diatoms 8

Big Dry Creek 8

Little Dry Creek 9

BIOASSESSMENT 10

LITERATURE CITED 12

MAPS OF SAMPLING SITES (follow page 14)

TABLES

Table 1
Table 2
Table 3

Table 4

Table 5

Table 6

Location of sampling sites

Diatom association metrics

Diatom criteria for evaluating biological integrity

in prairie streeims

Abundance of non-diatom algae in Big Dry Creek and

Little Dry Creek

Major diatom species and diatom metric values for

Big Dry Creek and Little Dry Creek

Bioassessment of Big Dry Creek (Protocol II)

APPENDIX A: DIATOM PROPORTIONAL COUNTS

SUMMARY

Composite periphyton samples were collected from natural
substrates in lower Big Dry Creek and lower Little Dry Creek in
eastern Garfield County, Montana. Samples were collected
following standard operating procedures of the Montana Department
of Environmental Quality, processed and analyzed using standard
methods for periphyton, and evaluated following modified USEPA
rapid bioassessment protocols for wadeable streams.

Most diatom association metrics indicated that Big Dry Creek
had good to excellent biological integrity when compared to
least-impaired reference streams elsewhere in eastern Montana.
However, a very low pollution index resulted in a rating of fair
biological integrity, moderate impairment, and only partial
support of aquatic life uses. The low pollution index was the
result of excessive organic loading, either from internal sources
or from wastewater discharges upstream, or both. The siltation
index also indicated problematic conditions in Big Dry Creek.

Potentially toxic blue-green algae were present in Big Dry
Creek, but not in sufficient quantities to pose a problem for
livestock producers.

All diatom metrics indicated full support of aquatic life
uses in Little Dry Creek when compared to other prairie streams .
Only a slightly depressed pollution index resulted in a rating of
good rather than excellent biological integrity. Little Dry
Creek proved to be a suitable local reference stream.

When compared to metric values for Little Dry Creek, the
pollution and siltation indexes for Big Dry Creek indicated only
minor impairment, good biological integrity, and full support of
aquatic life uses. The diatom species diversity index was within
the range of no impairment and excellent biological integrity.

i

INTRODUCTION

This report evaluates the biological integrity, support of
aquatic life uses, and probable causes of impairment to those
uses in Big Dry Creek and Little Dry Creek in Garfield County,
Montana. This evaluation is part of an assessment sponsored by
the Garfield County Conservation District with assistance from
the Natural Resources Conservation Service, U.S.D.A.

The evaluations in this report are based on the structure
and species composition of the periphyton or phytobenthos
community. The periphyton community is a basic biological
component of all aquatic ecosystems. Periphyton accounts for
much of the primary production and biological diversity of
Montana streams (Bahls et al . 1992).

Periphyton is a diverse assortment of simple photosynthetic
organisms called algae, and other microorganisms that live
attached to or in close proximity of the stream bottom. Many
algae, such as the diatoms, are microscopic. Diatoms are
distinguished by having a cell wall composed of opaline glass- -
hydrated amorphous silica. Diatoms often carpet a stream bottom
with a slippery brown film.

Some algae, such as the filamentous greens, are conspicuous
and their excessive growth may be aesthetically displeasing.
Algae may also deplete dissolved oxygen, interfere with fishing
and fish spawning, clog water filters and irrigation intakes,
create tastes and odors in drinking water, and generate toxins
that may be lethal to livestock and other animals.

Plafkin et al . (1989) and Stevenson and Bahls (1999) list
several advantages for using periphyton in biological assessments
of streams :

Algae are universally present in large numbers in all
streams and unimpaired periphyton assemblages typically
support a large number (>30) of species;

Algae have rapid reproduction rates and short life cycles,
making them useful indicators of short-term impacts;

As primary producers, algae are most directly affected by
physical and chemical factors, such as temperature,
nutrients, dissolved salts, and toxins;

Sampling is quick, easy and inexpensive, and causes minimal
damage to resident biota and their habitat;

Standard methods and criteria exist for evaluating the
composition, structure, and biomass of algal associations;

Identification to species is straightforward for the
diatoms, for which there is a large body of taxonomic and
ecological literature;

Excessive algae growth in streams is often correctly
perceived as a problem by the public.

Periphyton and other biological communities reflect the
biological integrity^ of waterbodies; restoring and
maintaining the biological integrity of waterbodies is a
goal of the federal Clean Water Act;

Periphyton and other biological communities integrate the
effects of different stressors and provide a measure of
their aggregate impact; and

Periphyton and other biological communities may be the only
practical means of evaluating impacts from non-point sources
of pollution where specific ambient criteria do not exist
(e.g., impacts that degrade habitat or increase nutrients).

^ Biological integrity is defined as "the ability of an
aquatic ecosystem to support and maintain a balanced, integrated,
adaptive community of organisms having a species composition,
diversity, and functional organization comparable to that of
natural habitats within a region" (Karr and Dudley 1981) .

PROJECT AREA AND SAMPLING SITES

The project area is located in Garfield County in east
central Montana. Big Dry Creek heads at an elevation of 3,500
feet south of Sand Springs in the southwestern corner of Garfield
county. Little Dry Creek heads south of Jordan at about the same
elevation. The two streams flow north and east to where they
join 26 miles east of Jordan along Montana Highway 200.

The project area is within the Northwestern Great Plains
Ecoregion (Woods et al . 1999) . The surface geology of the area
consists of sandstone and shales of t-he Hell Creek formation in
the headwaters and near the mouth of Big Dry Creek, and rocks of
the coal -bearing Fort Union Formation in between (Renfro and
Feray 1972) . Upland vegetation is predominantly mixed grassland
(USDA 1976) . The main land use is livestock grazing.

Periphyton samples were collected at one site each on Big
Dry Creek and Little Dry Creek (Table 1) . The site on Big Dry
Creek (#9) is about 2 miles upstream from Fort Peck Reservoir on
the Missouri River (Map 1) . The site on Little Dry Creek (Map 2)
is just above its confluence with Big Dry Creek, which is about 8
miles above Site #9 and 10 miles above Fort Peck Reservoir.

Elevations at the sampling sites are about 2,300 feet for
Big Dry Creek and 2,400 feet for Little Dry Creek. Big Dry Creek
and Little Dry Creek are classified C-3 in the Montana Surface
Water Quality Standards.

METHODS

Periphyton samples were collected following standard
operating procedures of the Planning, Prevention, and Assistance
Division of the Montana Department of Environmental Quality.

Using appropriate tools, microalgae were scraped, brushed, and/or
sucked from natural substrates in proportion to the rank of those
substrates at the study site. Macroalgae were picked by hand in
proportion to their abundance at the site. All collections of
microalgae and macroalgae were pooled into a common container and
preserved with Lugol ' s solution (APHA 1998) .

Samples were examined to estimate the relative abundance and
rank by biovolume of diatoms and genera of soft (non-diatom)
algae according to the method described in Bahls (1993) . Soft
algae were identified using Dillard (1999) , Prescott (1978) ,
Smith (1950) , and Whitford and Schumacher (1984) . These books
also served as references on the ecology of the soft algae, along
with Palmer (1977) .

After the identification of soft algae, raw periphyton
samples were cleaned of organic matter using sulfuric acid, and
permanent diatom slides were prepared using Naphrax, a high
refractive index mounting medium, following Standard Methods for
the Examination of Water and Wastewater (APHA 1998) . For each
slide, between 401 and 412 diatom cells (802 to 824 valves) were
counted at random and identified to species. The following were
used as the main taxonomic and autecological references for the
diatoms: Krammer and Lange-Bertalot 1986, 1988, 1991a, 1991b;
Patrick and Reimer 1966, 1975.

Lowe (1974) was also used as an ecological reference for the
diatoms. Bahls et al . (1984) provide autecological information
on important diatom species that live in the Fort Union Region of
Montana, including many of the diatom species found in Big Dry
Creek and Little Dry Creek.

The diatom proportional counts were used to generate an
array of diatom association metrics (Table 2) . A metric is a
characteristic of the biota that changes in some predictable way

with increased human influence (Barbour et al . 1999) .

Metric values for Big Dry Creek and Little Dry Creek were
compared to numeric biocriteria developed for streams in the
Great Plains Ecoregions of Montana (Table 3) . These criteria are
based on metric values measured in least- impaired reference
streams (Bahls et al . 1992) and on metric values measured in
streams that are known to be impaired by various sources and
causes of pollution (Bahls 1993) .

The criteria in Table 3 distinguish among four levels of
impairment and three levels of aquatic life use support: no
impairment or only minor impairment (full support); moderate
impairment (partial support) ; and severe impairment (nonsupport) .
These impairment levels correspond to excellent, good, fair, and
poor biological integrity, respectively.

Besides the ecoregional biocriteria listed in Table 3,
metrics for Big Dry Creek were also compared to metrics generated
from a local, least- impaired reference stream using Protocol II
in Bahls (1993) . Little Dry Creek was used as the local, least-
impaired reference stream.

Protocol II is based on the percentage of change in metric
values at the study site(s) from values measured at the local
reference stream. Criteria for evaluating biological integrity
using Protocol II are given in Table 12 in Bahls (1993) .

Protocol II may be used if a tributary stream is available
that fully supports its aquatic life uses, that is, if it has a
rating of "good" or "excellent" biological integrity using
Protocol I. Little Dry Creek exhibited only minor impairment
using Protocol I and thereby qualifies as a local reference site.

For Protocol I, only periphyton samples collected in summer
(June 21-September 21) can be compared with confidence to
reference stream samples because metric values change seasonally
and summer is the season in which reference streams and impaired
streams were sampled for the purpose of biocriteria development.
Protocol II can be used at any time of the year.

QUALTIY ASSURANCE

Several steps were taken to assure that the study results
are accurate and reproducible.

Upon receipt of the samples, station and sample information
were recorded in a laboratory notebook and samples were assigned
a unique number compatible with the Montana Diatom Database,
e.g., 1987-01. The first part of this number (1987) designates
the sampling site (Big Dry Creek Site #9) ; the second part of the
number (01) designates the number of periphyton samples that have
been collected at this site to date for which data have been
entered into the Montana Diatom Database.

Sample observations and analyses of soft (non-diatom) algae
were recorded in a lab notebook along with station and sample
information provided by Warren Kellogg of the NRCS . A portion of
the raw sample was used to make duplicate diatom slides.

On completion of the project, station information, sample
information, and diatom proportional count data will be entered
into the Montana Diatom Database. One set of diatom slides will
be deposited in the University of Montana Herbarium in Missoula.
The other set of slides will be retained bv Hannaea in Helena.

RESULTS AND DISCUSSION

Results are presented in Tables 4-6, located near the end of
this report following the Literature Cited section. Spreadsheets
containing completed diatom proportional counts, with species'
pollution tolerance classes and percent abundances, are attached
as Appendix A.

FIELD AND SAMPLE NOTES

Big Dry Creek Site #9. The periphyton sample from this
site consisted mainly of plant roots. The stream here formed
long pools of variable depth. The substrate was a mix of small
gravels and silt. Macrophytes were present along the channel
edges. Channel alterations and sediment accumulations were
minimal. Point bars were active but with little long-term
enlargement. The sinuosity was about 2.0-2.5. Banks were stable
with good vegetative cover. (Field notes by Warren Kellogg,
NRCS, 8/23/00.)

Little Dry Creek above Highway 200. The sample from this
site was very silty and was composed primarily of plant roots.
About 20% of the diatom cells were empty. Branching was observed
in Rhizoclonium, but it was rare. Two species of Oedogonium were
present. The habitat score for this site (115.5) was 68% of the
maximum possible (Carol Endicott, MDEQ, personal communication) .

NON- DIATOM ALGAE

Big Dry Creek

Big Dry Creek supported a mix of green algae, euglenoid
algae {Euglena) , diatoms, and cyanobacteria (formerly called
blue-green algae) (Table 4) . Eight genera of non-diatom algae
were present, which is less than the average number (13) recorded
for reference streams in Great Plains Montana (Bahls 1993).

Diatoms were the most abundant algae, followed by greens,
cyanobacteria, and euglenoids . Dominance by diatoms and greens
and the occasional cell of Euglena indicate moderate nutrient
enrichment and organic loading at this site. Nitrogen- fixing
cyanobacteria cannot compete successfully with diatoms and greens
under such conditions.

Anahaena was one of three nitrogen- fixing cyanobacteria in
Big Dry Creek. Under certain conditions, AnaJbaeria can produce
waterblooms that release neurotoxins into the water. These
toxins can be lethal to livestock, pets, and wildlife. However,

Anabaena was not abundant enough in Big Dry Creek to pose a
problem for livestock producers.

Little Dry Creek

The sample from Little Dry Creek also contained a mix of
green algae, diatoms, euglenoid algae, and cyanobacteria . Only
five genera of non-diatom algae were present .

Diatoms dominated the sample from Little Dry Creek, followed
by green algae, cyanobacteria, and euglenoids . Euglena, a good
indicator of organic loading, was rare at this site.

Big Dry Creek and Little Dry Creek had only three genera of
non-diatom algae in common: Oedogonium, Euglena, and Phormidium.
The absence of Anahaena and the abundance of the filamentous
green alga Rhizoclonium indicates that Little Dry Creek probably
had cooler water and more water movement than did Big Dry Creek.
It should also be noted that the sample from Little Dry Creek was
collected in the Spring, when higher flows and cooler waters are
to be expected. The sample from Big Dry Creek was collected in
late Summer of a particularly dry year (2000) .

DIATOMS

Big Dry Creek

The major diatom species in Big Dry Creek were all somewhat
tolerant to very tolerant of nutrient enrichment, organic
loading, and elevated dissolved solids (Table 5) .

The dominant diatom in Big Dry Creek was Navicula
duerrenhergiana. This diatom has been reported mainly from
/ brackish seas and coastal waters in Europe and Israel (Kraramer

and Lange-Bertalot 1986) . In Montana, Navicula duerrenbergiana

is most common in silty prairie streams, including the lower
reaches of the Redwater and Musselshell Rivers (unpublished
data) . In the Southern Fort Union Coal Region, this taxon has
been reported from the lower reaches of Armells, Mizpah, Pumpkin,
and Rosebud Creeks, where it prefers warm, brackish waters and
tolerates some suspended sediment and turbidity (Bahls et al .
1984) .

Next in abundance in Big Dry Creek was Diploneis puella.
This diatom prefers brackish waters with muddy bottoms. Next in
abundance was Navicula recens . In Europe, N. recens is common in
brackish waters and in large rivers, such as the Rhein and the
Weser (Krammer and Lange-Bertalot 1986) .

Also common in Big Dry Creek, and to a lesser extent in
Little Dry Creek, was Nitzschia palea. This diatom is very
tolerant of organic loading and of low levels of dissolved
oxygen. It is a good indicator of nitrogen enrichment.

Little Dry Creek

Diploneis puella- -the diatom that prefers brackish waters
with muddy bottoms- -was also a major diatom species in Little Dry
Creek (Table 5) . However, also abundant here were Achnanthes
minutissima and Cymbella af finis. Both of these diatoms prefer
cool, flowing waters and do not tolerate heavy organic loading or
low concentrations of dissolved oxygen. They are sensitive to
pollution and are the dominant diatoms in many mountain streams
of central and western Montana (unpublished data) .

BIOASSESSMENT

PROTOCOL I

Most diatom association metrics for Big Dry Creek indicated
good to excellent water quality and biological integrity when
compared to least- impaired reference streams elsewhere in eastern
Montana {Table 5) . However, a very low pollution index resulted
in a rating of fair biological integrity, moderate impairment,
and only partial support of aquatic life uses.

The source of the organic loading that resulted in this low
pollution index is unknown. It may be natural in origin, that
is, internal organic loading resulting from the decay of aquatic
plants. Or, it may originate from wastewater discharges upstream
in the Jordan area. Or, most likely, it is a combination of
these two sources.

A low species diversity index and a large siltation index
indicated minor impairment yet good biological integrity and full
support of aquatic life uses in Big Dry Creek. However, the
siltation index was within one percentage point of the threshold
for moderate impairment for a prairie stream. Such a rating
would correspond to fair biological integrity and only partial
support of aquatic life uses.

All diatom metrics indicated full support of aquatic life
uses in Little Dry Creek when compared to other prairie streams
(Table 5) . Only a slightly depressed pollution index resulted in
a rating of good rather than excellent biological integrity.
Little Dry Creek proved to be a suitable local reference stream
for use in Protocol II.

10

PROTOCOL II

The index of similarity between the two streams was 36.86
(Table 6), indicating that the study stream (Big Dry Creek)
shared only about a third of its diatom association with the
local reference stream (Little Dry Creek) . Normally, such a low
similarly index would indicate that some perturbation had caused
the the diatom association of Big Dry Creek to be quite different
(from that of Little Dry Creek) and that the stream had been
moderately impaired. However, the two streams were sampled at
different times of the year. Since the abundance of diatom
species is highly seasonal, sampling in different seasons may
explain much of the floristic difference between the two streams.

When compared to metric values for Little Dry Creek, the
pollution and siltation indexes for Big Dry Creek indicated only
minor impainnent , good biological integrity, and full support of
aquatic life uses. The diatom species diversity index was within
the range of no impairment and excellent biological integrity
when compared to Little Dry Creek.

11

LITERATURE CITED

APHA. 1998. Standard Methods for the Examination of Water and
Wastewater. 20th Edition. American Public Health
Association, Washington, D.C.

Bahls, L.L. 1979. Benthic diatom diversity as a measure of
water quality. Proc . Mont. Acad. Sci . 38:1-6.

Bahls, L.L. 1980. Salinity and The Structure of Benthic Algae
(Periphyton) Communities in Streams of the Southern Fort
Union Region, Montana. Environmental Sciences Division,
Montana Department of Health and Environmental Sciences,
Helena .

Bahls, L.L. 1993. Periphyton Bioassessment Methods for Montana
Streams (Revised) . Montana Department of Health and
Environmental Sciences, Helena.

Bahls, L.L., Bob Bukantis, and Steve Tralles. 1992. Benchmark

Biology of Montana Reference Streams . Montana Department of
Health and Environmental Sciences, Helena.

Bahls, L.L., E.E. Weber, and J. 0. Jarvie . 1984. Ecology and
Distribution of Major Diatom Ecotypes in the Southern Fort
Union Coal Region of Montana. U.S. Geological Survey
Professional Paper 1289, U.S. Government Printing Office,
Washington.

Barbour, M.T., J. Gerritsen, B.D. Snyder, and J.B. Stribling.

1999. Rapid Bioassessment Protocols for Use in Streams and
Wadeable Rivers: Periphyton, Benthic Macroinvertebrates and
Fish. Second Edition. EPA/841-B-99-002 . U.S. EPA, Office
of Water, Washington, D.C.

Dillard, G.E. 1999. Common Freshwater Algae of the United
States. J. Cramer, Berlin.

Johansen, J.R. 1999. Diatoms of Aerial Habitats. Chapter 12 in
Stoermer, E.F., and J. P. Smol (eds.). The Diatoms, Cambridge
University Press, New York.

Karr, J.R., and D.R. Dudley. 1981. Ecological perspectives on
water quality goals. Environmental Management 5:55-69.

Klarich, D.A., and S.M. Regele. 1980. Structure, General
Characteristics, and Salinity Relationships of Benthic
Macroinvertebrate Associations in Streams Draining the
Southern Fort Union Coalfield Region of Southeastern
Montana. Environmental Sciences Division, Montana
Department of Health and Environmental Sciences, Billings.

12

Krammer, K., and H. Lange-Bertalot . 1986. Bacillariophyceae,
Part 2, Volume 1: Naviculaceae . In Ettl, H., J. Gerloff,
H. Heynig, and D. Mollenhauer (eds.), Freshwater Flora of
Middle Europe. Gustav Fischer Publisher, New York.

Krammer, K., and H. Lange-Bertalot. 1988. Bacillariophyceae,
Part 2, Volume 2: Bacillariaceae , Epithemiaceae,
Surirellaceae. In Ettl, H., J. Gerloff, H. Heynig, and D.
Mollenhauer (eds.). Freshwater Flora of Middle Europe.
Gustav Fischer Publisher, New York.

Krammer, K., and H. Lange-Bertalot. 1991a. Bacillariophyceae,
Part 2, Volume 3: Centrales, Fragilariaceae, Eunotiaceae.
In Ettl, H., J. Gerloff, H. Heynig, and D. Mollenhauer
(eds.). Freshwater Flora of Middle Europe. Gustav Fischer
Publisher, Stuttgart.

Krammer, K., and H. Lange-Bertalot. 1991b. Bacillariophyceae,
Part 2, Volume 4: Achnanthaceae, Critical Supplement to
Navicula (Lineolatae) and Gomphonewa, Complete List of
Literature for Volumes 1-4. In Ettl, H., G. Gartner, J.
Gerloff, H. Heynig, and D. Mollenhauer (eds.). Freshwater
Flora of Middle Europe. Gustav Fischer Publisher, Stuttgart.

Lange-Bertalot, Horst . 1979. Pollution tolerance of diatoms as
a criterion for water quality estimation. Nova Hedwigia
64 :285-304 .

Lange-Bertalot, Horst. 1993. 85 Neue Taxa Und Uber 100 Weitere
Neu Definierte Taxa Erganzend Zur Susswasserf lora Von
Mitteleuropa Vol. 2/1-4. Bibliotheca Diatomologica, Band
27. J. Cramer, Berlin.

Lowe, R.L. 1974. Environmental Requirements and Pollution
Tolerance of Freshwater Diatoms. EPA-670/4-74-005 .

McFarland, B.H., B.H. Hill, and W.T. Willingham. 1997. Abnormal
Fragilaria spp . (Bacillariophyceae) in streams impacted by
mine drainage. Jour, of Freshwater Ecology 12 (1) : 141-149 .

Omernik, J.M., and A.L. Gallant. 1987. Ecoregions of the West

Central United States (map). U. S. Environmental Protection
Agency, Corvallis, Oregon.

Palmer, CM. 1977. Algae and Water Pollution: An Illustrated
Manual on the Identification, Significance, and Control of
Algae in Water Supplies and in Polluted Water.
EPA-600/9-77-036 .

Patrick, Ruth, and C.W. Reimer. 1966. The Diatoms of The United
States Exclusive of Alaska and Hawaii. Volume 1:
Fragilariaceae, Eunotiaceae, Achnanthaceae, Naviculaceae.

13

Monograph Number 13, The Academy of Natural Sciences,
Philadelphia .

Patrick, Ruth, and C.W. Reimer. 1975. The Diatoms of The United
States Exclusive of Alaska and Hawaii. Volume 2, Part 1:
Entomoneidaceae, Cymbellaceae, Gomphonemaceae,
Epithemiaceae . Nonograph Number 13, The Academy of Natural
Sciences, Philadelphia.

Plafkin, J.L., M.T. Barbour, K.D. Porter, S.K. Gross, and R.M.
Hughes. 1989. Rapid Bioassessment Protocols for Use in
Rivers and Streams: Benthic Macroinvertebrates and Fish.
EPA 440-4-89-001.

Prescott, G.W. 1978. How to Know the Freshwater Algae. Third
Edition. Wm. C. Brown Company Publishers, Dubuque, Iowa.

Renfro, H.B., and D.E. Feray. 1972. Geological Highway Map of

the Northern Rocky Mountain Region. American Association of
Petroleum Geologists, Tulsa, Oklahoma.

Smith, G.M. 1950. the Fresh-Water Algae of The United States.
McGraw-Hill Book Company, New York.

Stevenson, R.J., and L.L. Bahls. 1999. Periphyton Protocols.
Chapter 6 in Barbour, M.T., J. Gerritsen, B.D. Snyder, and
J.B. Stribling. Rapid Bioassessment Protocols for Use in
Streams and Wadeable Rivers: Periphyton, Benthic
Macroinvertebrates and Fish. Second Edition. EPA/841-B-99-
002. U.S. EPA, Office of Water, Washington, D.C.

Stevenson, R.J., and Y. Pan. 1999. Assessing Environmental

Conditions in Rivers and Streams with Diatoms. Chapter 2 in
Stoermer, E.F., and J. P. Smol (eds.). The Diatoms:
Applications for the Environmental and Earth Sciences.
Cambridge University Press, New York.

USDA. 1976. Climax Vegetation of Montana (map). U. S.

Department of Agriculture, Soil Conservation Service,
Cartographic Unit, Portland.

Whitford, L.A., and G.J. Schumacher. 1984. A Manual of Fresh-
Water Algae (Revised) . Sparks Press, Raleigh, North
Carolina .

Whittaker, R.H. 1952. A study of summer foliage insect

communities in the Great Smoky Mountains. Ecological
Monographs 22:1-44.

Woods, A.J., Omernik, J.M., Nesser, J. A., Shelden, J., and

Azevedo, S.H. 1999. Ecoregions of Montana (color poster

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Table 1. Location of periphyton stations on Big Dry Creek and

Little Dry Creek near Jordan, Montana: Station codes,
sample numbers in the Montana Diatom Database, sample
dates, and legal descriptions.

Location Station Sample Sample Legal

Code Number Date Description

Big Dry Creek at

Monte Billing Place Site #9 1987-01 8/23/00 T20NR42E34DB
above ford

Little Dry Creek L. Dry 0745-02 5/27/99 T18NR42E09AA

at Highway 2 00

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Table 4. Relative abundance of cells and rank by biovolume of
diatoms and genera of non-diatom algae in periphyton
samples collected from Big Dry Creek and Little Dry
Creek near Jordan, Montana.

Taxa

Relative Abundance and (Rank)

Big Dry Creek
(8/23/00)

Chlorophyta (green algae)
Anki s trodesmus
Bulbochaete
Cosrnari um
Oedogonium
Rhizoclonium
Spirogyra

occasional (8)

occasional (3)

occasional (4)

common ( 2 )

Little Dry Creek
(5/27/99)

frequent (3)
abundant (2)
frequent (4)

Euglenophyta (euglenoid algae)

Euglena occasional (9)

rare (6)

Chrysophyta (golden algae)
Bacillariophyceae

frequent (1)

abundant ( 1 ;

Cyanophyta (cyanobacteria) ^
Anajbaena
Calothrix
Phormidium

occasional {6[
occasional (7;
occasional (5]

common ( 5 )

^ Formerly known as blue-green algae.

Table 5. Percent abundance of major diatom species^ and values
of selected diatom association metrics for periphyton
samples collected from Big Dry Creek and Little Dry
Creek near Jordan, Montana.

Species /Metric
{Pollution Tolerance Class) ^

Percent Abundance/Metric Values^

Big Dry Creek
(8/23/00)

Little Dry Creek
(5/27/99)

Achnanthes minutissima (3)
CyjTijbella af finis (3)
Diploneis puella (2)
Entowoneis paludosa (2)
Gomphonewa parvulum (!)
Navicula duerrenbergiana (1
Navicula recens (2)
Nitzschia frustulum (2)
Nitzschia palea (1)

Cells Counted
Total Species
Species Counted
Species Diversity
Percent Dominant Species
Disturbance Index
Pollution Index
Siltation Index
Percent Abnormal Cells
Percent Epithemiaceae
Similarity Index

16.

1.

6.
21.
11 .

5.

9.

99
33
19
72
89
83
22

412

48

45
3 .90

21.72
0.00
1.56

69.66
0.00
1.09

9,

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7,

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17,

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5.

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0,

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0,

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68

66

4 .

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9.

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2.

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37.

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0.

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0.

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36.86

A major diatom species is here considered to be one that
accounts for 5% or more of the cells in one or more samples of
a sample set .

Underlined values indicate good biological integrity, minor
impairment, and full support of aquatic life uses; bold values
indicate fair biological integrity, moderate impairment, and
partial support of aquatic life uses; all other values
indicate excellent biological integrity, no impairment,
and full support of aquatic life uses when compared to diatom
criteria for mountain and plains streams in Tables 3 and 4 .

3 = sensitive to pollution; 2 = tolerant of pollution;
1 = most tolerant of pollution.

A "p" indicates that the taxon was recorded as present during
a preliminary floristic scan of the diatom slide, but it was
not encountered during the diatom proportional count.

Table 6. Metric scores and impairment ratings for Big Dry Creek
based on a comparison with Little Dry Creek, following
Protocol II and Table 12 in Bahls (1993) . Underlined
values indicate full support of aquatic life uses,
minor impairment, and good biological integrity; bold
values indicate partial support of aquatic life uses,
moderate impairment, and fair biological integrity; all
other values indicate full support of aquatic life
uses, no impairment, and excellent biological
integrity.

Metric Metric Score (%)

Shannon Diversity Index 80.91

Pollution Index 77 . 61

Siltation Index 53 .32

Similarity Index 36.86

APPENDIX A: DIATOM PROPORTIONAL COUNTS

Big Dry Creek above ford at Monte Billing place (site 9)

11/15/00

s Sample Genus/SpeclesA/amty

Pollutfon Tolerarjce Cfeiss

CcHinf

Percent

198701 Amphora veneta

1

0

0.00

198701 Caloneis baciiium

2

1

0.12

198701 Caloneis schumanniana

2

5

0.61

198701 Cyclotella nneneghiniana

2

1

0.12

198701 Cymbella pusilla

1

2

0.24

198701 Cymbella silesiaca

2

6

0.73

198701 Diploneis puella

2

140

16.99

198701 Entomoneis alata

2

1

0.12

198701 Entomoneis paludosa

2

11

1.33

198701 Gomphonema gracile

2

2

0.24

198701 Gomphonema parvulum

1

51

6.19

198701 Gyrosigma spencerii

2

0

0.00

198701 Navicula ammophila

2

1

0.12

198701 Navicula capitata

2

0

0.00

198701 Navicula caterva

2

7

0.85

198701 Navicula cincta

1

6

0.73

198701 Navicula cryptotenella

2

2

0.24

198701 Navicula duerrenbergiana

1

179

21.72

198701 Navicula erifuga

2

24

2.91

198701 Navicula omissa

1

4

0.49

198701 Navicula pupula

2

4

0.49

198701 Navicula pygmaea

2

2

0.24

198701 Navicula recens

2

98

11.89

198701 Navicula tenelloides

1

9

1.09

198701 Navicula veneta

1

21

2.55

198701 Neidium ampliatum

3

1

0.12

198701 Nitzschia amphibia

2

8

0.97

198701 Nitzschia archibaldii

2

3

0.36

198701 Nitzschia clausii

2

2

0.24

198701 Nitzschia filiformis

2

17

2.06

198701 Nitzschia fmstulum

2

48

5.83

198701 Nitzschia gracilis

2

3

0.36

198701 Nitzschia incognita

2

2

0.24

198701 Nitzschia liebetruthii

2

4

0.49

198701 Nitzschia lorenziana

2

2

0.24

198701 Nitzschia microcephala

1

4

0.49

198701 Nitzschia palea

1

76

9.22

198701 Nitzschia paleacea

2

2

0.24

198701 Nitzschia reversa

2

32

3.88

198701 Nitzschia solita

1

2

0.24

198701 Nitzschia valdestriata

2

6

0.73

198701 Pleurosigma delicatulum

2

6

0.73

198701 Rhopalodia brebissonii

1

4

0.49

198701 Rhopalodia gibba

2

3

0.36

198701 Rhopalodia operculata

1

2

0.24

198701 Surirella brebissonii

2

6

0.73

198701 Synedra acus

2

1

0.12

198701 Synedra delicatissima

2

13

1.58

Page 1

Little Dry Creek at Highway 200

11/5/00

;:;|g;|jjP^jgm!pi:?sSsjgg:fj]^

1 Polfotjon Tdlerinci'^iiiii

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IP^riwiiiii

074502Achnanthes minutissima

3

75

9.35

074502^mphipleura pellucida

2

9

1.12

074502 Amphora dusenii

2

4

0.50

074502 Amphora inariensis

3

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0.25

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3

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0.25

074502 Caloneis bacillum

2

2

0.25

074502'Caloneis schumanniana

2

6

0.75

074502!Cylindrotheca gracilis

2

4

0.50

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3

61

7.61

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3

10

1.25

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2

27

3.37

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2

3

0.37

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2

14

1.75

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1

6

0.75

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2

1

0.12

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2

15

1.87

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2

10

1.25

074502iDlploneis puella

2

142

17.71

074502 Entomoneis alata

2

4

0.50

074502'Entomoneis paludosa

2

44

5.49

074502:Fragilaria vaucheriae

2

36

4.49

074502iGomphonema parvulum

1

2

0.25

074502;Gyrosigma spencerii

2

2

0.25

074502 Navicula accomoda

1

1

0.12

074502INavicula capitata

2

4

0.50

074502iNavicula capitatoradiata

2

1

0.12

074502|Navicula caterva

2

10

1.25

074502 Navicula cincta

1

5

0.62

074502

Navicula cincta v. rostrata

1

32

3.99

074502

Navicula circumtexta

1

1

0.12

074502iNavicula cryptocephala

3

2

0.25

074502Navicula cryptotenella

2

16

2.00

074502!Navicula cuspidata

2

4

0.50

074502

Navicula duerrenbergiana

1

3

0.37

074502;Navicula erifuga

2

13

1.62

074502:Navicula gregaria

2

5

0.62

074502INavicula minuscula

1

7

0.87

074502 Navicula notha

2

3

0.37

074502lNavicula odiosa

1

2

0.25

074502iNavicula reichardtiana

2

2

0.25

074502

Navicula veneta

1

5

0.62

074502 Navicula viridula v. rostellata

2

3

0.37

074502iNitzschia amphibia

2

8

1.00

074502

Nitzschia apiculata

2

10

1.25

074502

Nitzschia bergii

1

8

1.00

074502jNitzschia filiformis

2

7

0.87

074502

Nitzschia frustulum

2

0

0.00

Page 1

Little Dry Creek at Highway 200

11/5/00

Sample Genus/Species/Variety

PoHutJoii Tolerance Class

Count

Pere«tt

074502 Nitzschia frustulum v. subsalina

2

5

0.62

074502 Nitzschia gracilis

2

4

0.50

074502:Nitzschia levidensis

2

4

0.50

074502iNitzschia microcephala

1

6

0.75

074502iNitzschia palea

1

68

8.48

074502 Nitzschia paleacea

2

21

2.62

074502:Nitzschia perminuta

3

2

0.25

074502iNitzschia perspicua

1

5

0.62

074502:Nitzschia recta

3

3

0.37

074502 Nitzschia reversa

2

4

0.50

074502 Nitzschia Sigma

2

2

0.25

074502|Nitzschia solita

1

0

0.00

074502

Nitzschia valdestriata

2

6

0.75

074502

Pinnularia microstauron

2

4

0.50

074502 Rhoicosphenia curvata

3

4

0.50

074502!Simonsenia delognei

2

4

0.50

074502 Stauroneis tackei

2

2

0.25

074502.Stephanodiscus hantzschii

2

6

0.75

074502 Surirella brebissonii

2

16

2.00

074502iSynedra delicatissima v. angustiss

2

1

0.12

074502 Synedra fasciculata

2

2

0.25

Page 2