Analysis of the sampled fish communities used 

 Integrated Biotic Indices (IBI) (Brambiett et al. 

 2005) and derived ()bser\ed/i;xpected (()/!•) Fish 

 Models(Stag!iano2005)todetect impairment in the 

 biological integrity of the sites. Ihe IBI involved 

 calculation of a series of metrics evaluating 

 ditTerent attributes of the community (Table 2). 

 The metrics allowed calculation otan overall score 

 between and 100. Bramblen et al. (2005) did not 

 propose threshold criteria for good, fair, and poor 

 biological integrity for these scores. Iherefore, we 

 applied commonly used criteria. Scores of 75 to 

 1 00 indicate good to excellent biological integrity, 

 50-74 fair to good biological integrity, 25 to 49 

 indicated poor to fair biological integrity and scores 

 <25% indicate poor biological integrity or severely 

 impaired. 



Macroin vertebrate Communities 



Macroin\ertebrates were collected from all 

 habitats that we could wade w ithin the sampling 

 reach of the streams (Figure 8). Sampling involved 

 multi-habitat. c|iialitati\c methods outlined in the 

 EPA protocols (Barbour ctal. 19W). Cobble 

 substrates, vegetation, woody debris and bank-side 

 areas were sampled qualitatively with a 500-micron 

 D-frame net within the designated transects. A 

 total of Iwcnt) habitat-weighted, randomized 0.5m 

 jabs or kicks were conducted within the reach, 

 allow ing 1 seconds per kick and composited into 

 one sample. All organisms in the net were washed 

 on a 500-micron sieve, transferred to a 1 liter 

 Nalgene bottle, labeled and preserved in 95% 



Figure H. Atulli-hahiiai mavroinvcriehrulu sumpliny^ 

 usiriji IJ'A protocols. 



ethanol and brought to the M fNHP lab in Helena 

 for processing. 



These samples were processed (sorting, 

 identification, and data analysis) by David Stagliano 

 at the Helena lab follow ing DF,0 protocols (MT 

 DliQ 2005). Macroinvertebrates were identified to 

 the lowest ta.xonomic level, imported into 1:DAS 

 (Jessup 2006), and biological metrics were 

 calculated from the data using the Montana 

 Department of Ijivironmcntal Qualitv's newest 

 multimetric macroinvertebrate (MMI) protocols 

 (Jessup et al. 2005. Feldman 2006). Metric results 

 were then scored using the Montana DFQ 

 bioassessment criteria and each sample categorized 

 as non-impaired or impaired according to threshold 

 values (Table 3). 



The macroinvertebrate MMI score is based upon a 

 series of metrics that measure attributes of benthic 

 macroinvertebrate communities regarding condition 

 changes to a stream s\stcm ( in the form of 

 pollution or pollutants). Ihe invertebrate metrics 

 include: EPT Taxa Richness (Score = F.PT 

 richncss/i4*100): Iplienieriiptcra. I'lecoptera 

 &Trichoptera ta.xa; Percent Tanypodinae (Score 

 = PcrccntTanypodinac/M) *!(>0): Percent 

 Orthocladiinae of C'hiron(»midae (Score = 

 (100-pcrccnt Orthocladiinae of Chironomidae/ 

 nU))*l(M)); Predator Taxa Richness (.Score = 

 number of predator taxa/9*100); Percent 

 Collectors and Filterers (Score = (KM) - 

 percent collectors and rilterers/65)*100): Ihis 

 metric measures the relative abundance oi' 

 collector and tllterer taxa in the sample. Hie index 

 score represents the condition of the 

 macroinvertebrate commiinit\ at the time the 

 sample was collected within that past \ear. If the 

 index score is below the impairment threshold, the 

 iiidi\ idiial metrics can be used to pnn ide insight as 

 to wh\ llie ci>mniuiiities arc ditTerenl Irom the 

 reference condition ( Barbour et al. 1 999, Jessup et 

 al. 2005). Ihc impairmenl threshold set b> Ml 

 1)1. (,) is 37 lor ihe I aslern Plains Stream Index; 

 thus any scores above this threshold are considered 

 unimpaired South Dakoia does not \el lia\e 

 iiiacroimertebrate models to calculate scores. For 

 ihe Observed/Iixpected (O/E) scores, taxa in liic 

 sample were compared to their expected 

 macroiiuerlebrate indicator species for that 

 classilled prairie aquatic ecological type (Stagliano 

 2005) (Appendix C). 



