s 333.955 E30aifs 2002 MONTANA STATE LIBRARY l|ll|lll|l|iiiii|i|ini iiiiiiii|iii|iiiiiiiiiiiii|iii| 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