Aquatic invertebrates and habitat at a fixed station on the Powder River, Custer County, Montana : July 26, 2001 PDF
Preview Aquatic invertebrates and habitat at a fixed station on the Powder River, Custer County, Montana : July 26, 2001
1 S MONTANASTATELIBRARY 333.955 E30aifs 3 0864 1001 9402 9 2002 AQUATIC INVERTEBRATES AND HABITAT AT A FIXED STATION ON THE POWDER RIVER, CUSTER COUNTY, MONTANA July 26, 200 STATE DOCUMENTS COLLECTION MAY fl 1 2003 MONTANA STME 'L"I"B:'/" 1515 - - ' A report to the Montana Department ofEnvironmentalQuality Helena, Montana by WeaseBollman RhithronAssociates, Inc. Missoula, Montana May2002 . INTRODUCTION Thisreport isoneof38 briefinterpretive summaries ofdataassembled aspart of astatewide, multi-yearstudyconducted bythe Montana DepartmentofEnvironmental Quality(MTDEQ). Eachreport discusses informationgenerated fromasingle benthic invertebrate samplecollectionand habitat evaluationat a fixed stationestablished ona gauged riverorhigh-ordertributary. Thepresenttreatise focusesontheaquatic communitysampled onthe PowderRivernearthe communityofLocate inCuster County, MontanaonJuly26, 2001. The sample sitewaslocated byGPS readingat46° 25' 31"N, 105° 18'23" W. lyingwithintheNorthwesternGreat PlainsEcoregion (Woods et al. 1998). The sample wascollected bypersonnelofMTDEQ. Samplingeffort consistedofeitheracompositeoffourHesssamples, oraone-minutekicknetcollection (Bukantis 1998). Habitat parameterswereevaluated usingtheMTDEQ Macroinvertebrate Habitat Assessment Field Form forstreamswithriffle/runprevalence. Invertebrate sampleswereprocessed and animals identified byRhithronAssociates, Inc. Analysisofinvertebrateswasaccomplishedbyapplyingthe method recommendedby Bukantis (1998) forstreamsofMontana'sPlainsEcoregions. Themethod usesa multimetric batteryto evaluate disturbanceto biotic integrity. Results fromthe applicationofothermetric batteries maybe found inthe Appendix. RESULTS AND DISCUSSION Table 1 itemizesthenine evaluatedhabitat parametersand showstheassigned scoresforeach, aswellasthe integrated scoreandconditioncategory. Table 1. Streamand riparianhabitat assessment forafixed stationonthe PowderRiver, nearLocate, Montana. July2001 Max.possible score streambanksreported inthe assessment. Notesindicatethat erosion on outsidebanks appearedto benatural Riparian conditionswerejudged optimal Bioassessment resultsaregiven inTable2. Whenthisbioassessment method is appliedtothesedata, scoresindicatethatthis siteonthePowderRiverismoderately impaired and onlypartially supports designated uses. However, verylowabundanceof organismsinthe sample(only 13 animalswerecollected) complicatestheevaluation, conclusionsand interpretation ofresultsaretenuous. Whethertheinadequacy ofthe samplewasdueto a depauperate community atthe siteorto samplingbiasisnot clear fromthe dataitself, however, the habitat assessment suggeststhat the natureofthe benthic substratemaylimitbenthic assemblages. Table2. Metricvalues, scores, and bioassessment forafixed stationonthePowder River. TheMontanaDEQbioassessment metricbatteryrecommended forstreams of Montana'sPlains ecoregions (Bukantis 1998)wasused fortheevaluation July 2001. Extremely lowabundance oforganisms rendersthe score, classification, anduse support designationunreliable CONCLUSION • Low abundance oforganismsinthe sample prohibits assessment ofthe sitebased oninvertebrate assemblages. Filter-feedersrepresented 85% oftheanimals collected, and 3 ofthe 5 taxapresent werewarm stenotherms. LITERATURE CITED Bukantis.R. 1998. Rapidbioasscssnicnlmacroinvcrtcbratcprotocols: Samplingandsampleanalysis SOP's Workingdraft. April22. 1997. MontanaDepartmentofEnvironmentalQuality. Planning PreventionandAssistanceDivision. Helena.Montana. Woods. A.J. Omernik.J. M.Nesser.JA.. Shelden.J.,andAzevedo. S.H. 1999.EcoregionsofMontana (Colorposterwithmap.descriptivetext,summarytables,andphotographs): Reston. Virginia. US GeologicalSurvey APPENDLX Taxonomic data and summaries Powder Riverat Locate July 2001 AquaticInvertebrateTaxonomicData SiteName: PowderRivernearLocate SiteID: Y21POWDR01 7/26/01 Approx percentofs nplcuscd 10 Taxon Quantity Percent HBI 1FG Fallceonquillen Tricorythodesminutus GrandTotal 13 100.00 Aquaticln>erle SiteName:Pow SiteII):>21I'Q\M>RII1 SAMPLETOTAL DOMINANCE TAXON ABUNDANCE PERCENT EPTabundance Simuiiumsp 6 4615 TAXARICHNESS Cheumalopsychcsp 3 2308 NumberEPTtaxa Hydropsychesp 2 1538 PercentEPT Fallceonquillen 1 769 STnUcBorTyOlhTnAtLles5mDiOniMmIi*NANTS 131 10700609 TAXONOMICCOMPOSITION GROUP PERCENT KTAXA ABUNDANCE MiscTaxa
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