s
333.955
E30aifs
2002
MONTANA STATE LIBRARY
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3 0864 1002 0284 8
AQUATIC INVERTEBRATES AND HABITAT AT A FIXED
STATION ON THE FLATHEAD RIVER,
SANDERS COUNTY, MONTANA
August 11,2001
A report to
the Montana Department of Environmental Quality
Helena, Montana
by
uQ
Wease Bollman
t f
Rhithron Associates, Inc
%
Missoula, Montana
May 2002
INTRODUCTION
This report is one of 38 brief interpretive summaries of data assembled as part of
a statewide, multi-year study conducted by the Montana Department of Environmental
Quality (MT DEQ). Each report discusses information generated from a single benthic
invertebrate sample collection and habitat evaluation at a fixed station established on a
gauged river or high-order tributary. The present treatise focuses on the aquatic
community sampled on the Flathead River near Perma, Montana on August 1 1, 2001.
The sample site was located by GPS reading at 47° 20' 47" N, 1 14° 42' 15" W, lying
within the Montana Valley and Foothill Prairies Ecoregion (Woods et al. 1998). The
sample was collected by personnel of MT DEQ. Sampling effort consisted of a kicknet
collection taken near the edge of the river, since deep water and lack of riffles prohibited
other methods. Habitat parameters were evaluated usLng the MT DEQ Macroinvertebrate
Habitat Assessment Field Forms for streams with riffle/run prevalence. The habitat
evaluation was repeated using the form for streams with glide/pool prevalence.
Invertebrate samples were processed and animals identified by Rhithron Associates, Inc.
Analysis of invertebrate assemblages was accomplished by applying the revised method
(Bollman 1998) for streams of Western Montana's ecoregions. The method uses a
multimetric battery to evaluate disturbance to biotic integrity.
The revised bioassessment metric battery and its scoring criteria have not been
evaluated for application to higher-order streams and rivers; to date, no bioassessment
method has been contrived for these waterways in Montana. Thus, the method used here
is likely to have limitations in its applicability to the sites in this study. For example, 24
of the riverine or high-order waterways sampled for the fixed station study were located
within Western Montana ecoregions and were sampled between July 23 and August 25,
2001. Mean water temperature for these sites at the time of sampling was 19.8°C (median
= 19.4°). Temperatures ranged from 15.5°C (Kootenai River near Libby) to 25.3°C
(Jefferson River near Three Forks). Ninety-eight sites from Western Montana were used
to assemble the revised metric battery and to test it for sensitivity in detecting
impairment, to establish scoring criteria, and to improve robustness of bioassessment.
These 98 sites were mainly second and third order streams; the sampling season roughly
corresponded to that of the fixed-station study. Mean water temperature for these sites at
the time of sampling was 15°C (median = 14°C). Natural variations in benthic community
composition and structure along longitudinal and thermal gradients are well known
phenomena. Thus, scores and classifications were established for much smaller systems
with significantly lower water temperatures; impairment classifications and use support
designations in this study must be interpreted with care. Results from the application of
other metric batteries may be found in the Appendix.
RESULTS AND DISCUSSION
Tables 1 A and IB itemize the evaluated habitat parameters and show the assigned
scores for each, as well as the integrated score and condition category. Both riffle/run and
glide/pool evaluations were provided.
Both evaluations suggest that overall habitat conditions were sub-optimal at this
site. When riffle or run characteristics were evaluated, notable liniitations to habitat
quality were the lack of riffle development, and the marginal riparian zone width.
Substrate particle sizes were judged to be somewhat less diverse than expected. Some
Table 1 A. Stream and riparian habitat assessment for a fixed station on the Flathead
River. Riffle/run prevalence. August 2001.
Max. possible
score
Parameter
Flathead River near Perma
10
10
20
20
20
20
20
20
20
Riffle development
Benthic substrate
Embeddedness
Channel alteration
Sediment deposition
Channel flow status
Bank stability: left / right
Bank vegetation: left / right
Vegetated zone: left / right
2
7
18
16
15
16
8/8
8/6
5 /' 5
160
Total
114
Percent of maximum
CONDITION*
71
SUB-OPTIMAL
'Condition categones: Optimal > 80% of maximum score; Sub-optimal 75 - 56%, Margmal 49 - 29%;
Adapted Irom Piatkin et al. 1998.
Poor <23%.
Table IB. Stream and riparian habitat assessment for a fixed station on the Flathead
River. Glide/pool prevalence. August 2001.
Max. possible
score
Parameter
Flathead River near Perma
20
Bottom substrate
n.a.
20
Pool substrate char.
18
20
Pool variability
5
20
Channel alteration
16
20
Sediment deposition
17
20
Channel sinuosity
7
20
Channel flow staUis
16
20
Bank vegetation
8/6
20
Bank stability
8/8
20
Vegetated zone
5/5
180
Total
119
Percent of maximum
66
CONDITION*
SUB-OPTIMAL
♦Condition categones: Optimal (OPT) > 80% ofmaxunum score; Sub-optunal (SUB) ; 75 - 56%; Margmal (MARG)
49 - 29%; Poor <23%. Adapted trom Piatkin et al. 1998.
sediment deposition was noted. Wlien glide or pool characteristics were evaluated,
notable limitations to habitat quality were the absence of deep pools and the perception
that sinuosity was less pronounced than the ideal condition.
Bioassessment results are given in Table 2 When this bioassessment method is
applied to these data, scores indicate that this site on the Flathead River is moderately
impaired and only partially supports designated uses.
Table 2. Metric values, scores, and bioassessment for a fixed station on the Flathead
River The revised bioassessment metric battery (Bollman 1998) was used for the
evaluation. August 200 1 .
Flathead Ri\cr near Perma
METRICS
METRIC VALUES
METRIC SCORES
Ephemeroptcra richness
4
2
Plecoptera richness
Trichoptcra richness
■)
1
Number of sensitive taxa
Percent filterers
7.4
2
Percent tolerant taxa
82.1
TOTAL SCORE
(m;LX.= 18)
5
PERCENT OF MAX.
28
Impairment classification
MODERATE
USE SUPPORT
PARTIAL
The high biotic index value (6. 13) coupled with the low abundance of mayflies
suggests that water quality was impaired at this site. Impairment could have been due to
nutrient enrichment, temperature elevation, or both. No cold stenothermic animals were
present in the sample; many representatives of taxa that prefer warm water conditions
were collected These included the caddistlies Cheiimatupsyche sp dLnd Mystacides sp.,
the aquatic moth Petrophila sp., and several taxa of snails. The fianctional composition of
the assemblage was skewed toward scrapers, suggesting that substantial algal films were
present on hard substrates It is possible that nutrient enrichment promoted the growth of
algae supporting an abundance of scrapers Most of the scrapers were snails, which
typically prefer warmer, nutrient enriched waters. Excessive algal growth may have
compromised hard substrate habitats typically used by "dinger" taxa; only six of these
taxa were collected in the sample Warm, enriched conditions promote oxygen depletion
within substrates, and there was evidence of these anoxic conditions. The hemoglobin-
bearing midges Cryptochironomus sp., Dicrutcndipes sp., and Microteudipes sp. were all
present at the site.
Eighty percent of the animals in the sample were non-insects, and the composition
of this fauna suggests that thermal conditions may have been more or less static, muting
the temperature triggers essential to aquatic insect life histories
CONCLUSIONS
Impairment of water quality by warm temperatures and nutrient enrichment is
suggested by the high biotic index value, taxonomic composition, and functional
characteristics of the benthic assemblage.
The impairment classification assigned to this site by the bioassessment method
employed seems appropriate, given the taxonomic composition and tolerance
characteristics of the benthic assemblage.
•*»'-
LITERATURE CITED
BoUman. W 1998 Impro\ing Stream Bioassessment Methods for the Montana Valleys and Foothill
Frames Ecoregion. Master's (M.S.) Thesis. University of Montana. Missoula. Montana.
Bukantis, R. 1998. Rapid bioassessment macroinvertebrate protocols; Sampling and sample analysis
SOP's Working draft. Apnl 22. 1997 Montana Department of Environmental Qualit>. Planmng
Prevention and Assistance Division. Helena. Montana.
Woods. A. J.. Omemik. J. M. Nesser. J. A.. Shelden. J., and Azevedo, S. H. 1999. Ecoregions of Montana.
(Color poster with map. descriptive te.xt. summary tables, and photographs): Rcston. Virginia. US
Geological Survey.
APPEiNDLX
Taxonomic data and summaries
Flathead River
August 2001
Aquatic Invertebrate Taxonomic Data
Site Name: Flathead River near Perma
Site ID: C12FLATR01
Taxon
Date: 8/11/01
Approx. percent o
f sample used; 83
Quantity
Percent
HBI
FFG
9
2.68
PR
11
3.27
4
PR
1
0.30
11
PA
1
0.30
8
CG
1
0.30
10
PR
2
0.60
8
PR
1
0.30
8
CF
123
36.61
6
SC
7
2.08
8
SC
16
4.76
8
SC
18
5.36
4
SH
77
22.92
8
CG
2
0.60
8
CG
1
0.30
5
PA
Prostoma .sp.
Dugesia sp.
Nematoda
Eclipuinlus sp.
Helobdella stagnalis
Nephelopsis sp.
Pisidium sp.
Fossaria sp.
Physidae
Gyraulus sp.
Gammanis sp.
Hyalella azteca
Caecidotea sp.
Acan
Total Misc. Taxa
Coenagrionidae-early tnstar
Total Odonata
Drunella grandis
Stenonema sp.
Paraleptophlebia sp.
Paraleptophlehia hiconmta
Total Ephemeroptera
Cheumalopsyche sp.
Mvstacides sp.
Total Trichoptcra
Petruphila sp.
Total Lcpidoptera
Diihiraphia sp.
Oplioser-vus sp.
H all plus sp.
Total Coleoptera
Cncotopus Triiaseia Gr.
Cnpluchiroiiomus sp.
Dicrotendipes sp.
Microtendipes sp.
Nanocladius sp.
Rheotanytarsus sp.
Synorthocladius sp.
Tvetenia sp.
Total Chironomidae
270
80.36
0.30
0.30
0.30
1.49
0.60
0.60
10
2.98
10
1
2.98
0.30
11
3.27
2.08
2.08
4
10
1
1.19
2.98
0.30
15
4.46
2
1
2
10
1
4
1
1
0.60
0.30
0.60
2.98
0.30
1.19
0.30
0..30
22
6.55
2
3.5
1
2
7
8
8
6
3
6
2
5
PR
CG
SC
CG
CG
CF
CG
SC
CG
SC
PlI
CG
PR
CG
CF
CG
CF
CG
CG
Grand Total
336
100.00
Aquatic Invertebrate Summary
Site Name: Flathead River near Perma
SAMPLE TOTAL
EPT abundance
TAXA RICHNESS
Number EPT taxa
Percent EPT
TAXONOMIC COMPOSITION
Date: 8/11/01
Site ID: C12FLATR0I
336
21
33
6
6.2S
GROUP
PERCENT
Misc Taxa
80 36
Odonata
30
Ephemeropieta
2,98
Plecoptera
000
Hemiptera
000
Megaloplera
000
Tnchopiera
3 27
Lepidoptera
2.08
Coleoptera
446
Diplera
000
Chiroaomidae
6 55
trVAXA
ABUNDANCE
14
270
4
10
2
11
I
7
3
IS
Fu^cnONAL composition
GROUP
Predator
Parasite
Gatherer
Filterer
Herbivore
Piercer
Scraper
Shredder
Xy lophage
Omnivore
UnJmown
PERCENT
KTAXA
ABUNDANCE
744
6
25
060
2
2
28 87
13
97
744
4
25
000
030
1
1
50 00
6
168
5 36
1
IS
ooo
000
coo
■ Misc. Taxa
■ Odonata
3 EphentToptCTa
D Pltxopicra
■ (iLTlIiptCTa
■ Megalopti.T3
■ Trichoplera
D Lepidoptera
B (7olc(5ptcra
' □ Dipiera
O ChiiODonndae
■ Predator
■ Parasite
SI Gatherer
■ Fiitcrer
B I Icrbtvore
9 I'lercer
D Scraper
■ Shredder
D Xylophage
Q (>n¥iivDre
S I nknown
DOMINANCE
TAXON
ABUNDANCE
PERCENT
Fitssana sp
123
36 61
Hyalella azleca
T7
2192
Oammarus sp
18
536
Gyrautus sp
16
4 76
DuResia sp
11
327
SUBTOTAL 5 DONDNANTS
245
72 92
Chewtuilopsryche sp
10
298
Opttoservus sp
10
298
MicntienJipes sp
10
298
Prnstoma sp
9
2.68
Physidae
7
208
TOTAL DONUNANTS
291
86.61
SAPROBITV
HilsenhofTBiotic Index
6.13
DiVtRSITV
Shannon H (loge)
191
Shannon H (log2)
275
Simpson D
017
VOLTINISM
PiTE
.ABUNDANCE
PERCE^^■
Mullivoltine
32
9 52
Univoltme
280
83.33
Semivoltine
IS
446
TA.V\ CHARACTERS
STAXA
ABUNDANCE
PERCENT
Tolerant
13
276
8214
Intolerant
000
Clinger
6
32
9 52
BIOASSESSME.NT INDICES
B-ial.l^jrr«al
METRIC
VALUE
SCORE
Taxa nchness
33
3
E nchness
4
1
P nchness
1
T nchness
2
1
Long-hved
3
3
Sensitive richness
1
^'otolerant
82 14
I
"opredators
744
1
Clinger richness
6
1
"'odominanceO)
64 88
3
TOT.AL SCORE
16
MONTANA DEQ METRICS (Bukantis 1998)
METRIC
Taxa richness
EPT nchness
Biotic Index
%Dominant ta-\on
•/(.Collectors
%EPT
Shannon Diversity
•'oScrapets -*-Shredd
Predator la,xa
%Multivolline
%HotT
TOTAL SCORES
PERCENT OF MA.XIMUM
IMP.MRMENT CLASS
VALUE Phra Ikific^ns
6 13
36 61
36 31
625
175
55 36
6
9 52
909
7333
SLIGHT
Vaflcvs jnJ
FuDthdb
3
3
12
50 00
10
47 62
MODERATE MODERATE
Monuna DEQ metnc banenes
COMMLMITY TGLER/XiNCES
Sediment tolerant taxa
Percent sediment tolerant
Sediment sensitive taxa
Percent sediment sensitive
Metals tolerance mdex (McGuire)
Cold stenotherm ta.xa
Percent cold slenotherms
43 75
0,00
3 05
000
H 100
S 90
§ 70
in
B Plains Ecoregions
■ Valleys and Foothills
n Mountain Bcoregions
