Cover title

"January 2013"

Includes bibliographical references (pages 26-28)

Introduction -- Methods -- Results -- Conclusions -- Site Photos -- Literature Cited -- Appendix A. Fish data and IBI metric calculations collected from Otter Creek Project Sites -- Appendix B. Macroinvertebrate taxa list, abundance, and metrics for the 15 collection sites -- Appendix C. Stream Habitat and Water Quality Parameters measured for Otter Creek Sites

We summarize the second year of baseline surveys for the Assessment of Fish, Macroinvertebrates, and Herpetofauna in the Otter Creek coal tracts area. Project goals remain the same 1) to continue standardized surveys and collecting baseline information on the aquatic communities prior to coal development 2) to seasonally assess aquatic community integrity and condition with key indicators recorded at the sites and comparing these against biotic thresholds of reference condition standards. These 2012 data represent the second year of pre coal development (i.e. pre impact BACI design) conditions at the local reach scale. Habitat assessments herpetofauna, macroinvertebrate and fish surveys were performed during seasonally similar dates at the same sites visited in 2011 four mainstem Otter Creek reaches (control impact 2 and downstream) and three tributaries. In total, we performed 16 surveys for fish during the visits 12 at four mainstem Otter Creek reaches and four surveys in the tributary streams. Thirteen macroinvertebrate samples were collected during the visits; neither survey was conducted at Threemile Creek in any season due to lack of surface water present. All stream reaches were visually surveyed for amphibians or reptiles during all visits. Biological community integrity was calculated for 16 fish surveys using Fish Integrated Biotic Indices (IBIs) and ObservedExpected Models (OE) while the 13 macroinvertebrate samples were assessed with Montana DEQs multimetric indices (MT MMI). Habitat Evaluations. Of the seven sampling reaches evaluated in the study area we found three in Proper Functioning Condition (PFC) with a stable trend and four were Functional at Risk (FAR). Reasons that sites ranked FAR were likely due to anthropogenic habitat alteration by cattle (Home Creek Otter 1A and Threemile Creek Otter 3m) or stream manipulation (Otter Creek JT and Otter Creek 16). Highest site integrity scores using both the BLM Habitat and PFC Assessment methods were recorded at the Otter Creek sites 23 (Tenmile Creek) and 22 (control Denson reach). Sites with lower habitat scores were structurally degraded by cattle use and had high associated CPI values (Home Creek Threemile and Otter Creek 16 fall). Conductivity measurements recorded at all Otter Creek mainstem sites across most seasons were above the impairment threshold levels (>500, DEQ 2006), and the Home Creek site had visible signs of natural gas seepage from the sediments. Macroinvertebrate Communities Overall, 105 unique macroinvertebrate taxa were reported in 2012 from the 13 macroinvertebrate assessment samples. One mayfly species of concern (MTSOC), Caenis youngi was collected at the Otter Creek control site 22, which also reported the highest taxa richness (42 spp.) during the summer visit. Average macroinvertebrate richness per site was 29.8 taxa. The Montana DEQ multimetric index (MMI) ranked at least one sample of the five sites (9 of 13 samples) as nonimpaired (good biological integrity), and scores were not significantly different than 2011 scores (p 0.4). Three of the four samples that were ranked impaired were collected during the spring visit. Sites that maintained flowing water connectivity scored higher with the MMI than sites with interrupted pool areas. Overall, mainstem sites evaluated in the Otter Creek study scored significantly higher with MMI scores than those in the tributaries (ANOVA, p 0.01). MMIs did not significantly differ between Otter Creek mainstem Pre Impact Control, Impact or Downstream Sites (T test, p 0.05), despite fish communities reflecting a downstream decrease in biotic integrity. 3 Fish Communities. Overall, ten fish species (five native five introduced) were identified from 19,440 individuals collected during 16 surveys. We added one introduced fish species, the golden shiner, in 2012. One potential species of concern (PSOC), the brassy minnow, was collected at five sites. Average total fish species per Otter Creek mainstem site across all seasons was 7.0 (0.5 SE), a slight increase from 2011 (6.5), while the tributary sites with water averaged 1.5 species. Brassy minnows had the highest site occupancy rate at 88 (14 of 16 visits) followed by fatheads, lake chubs and white suckers at 81 and 75 (13 and 12 of 16 visits), respectively. Fathead minnows continue to account for the highest proportion of total individuals collected at 34. The most diverse fish sites in the study area were Otter Creek JT and Otter Creek 16 with nine species, while sites with the highest of native species were Otter Creek 22 (four spp.) and Home Creek (two native spp.). Using Montanas Prairie Fish IBI, 10 of the 16 fish visits ranked nonimpaired (good biological integrity), five were slightly moderately impaired and one was ranked poor biotic integrity. As in 2011, fish biotic integrity decreased going downstream in the Otter Creek mainstem, and the Pre Impact Control Site scored significantly higher than Downstream site (T test, p 0.05) but not the Impact sites (p 0.06) this year. The OE scores tracked the IBI ranks in most cases except in Otter impact site 2, where the OE showed a slight impairment (0.73), but the IBI scores good integrity. Further evaluations into the relationship of the OE to the IBI need to be addressed for non natives. Amphibian and Reptile Incidentals. All fish presence sites also reported at least one species of amphibian. Eight herpetofauna species were observed or collected in conjunction with the assessment surveys. Of the four amphibian species; the Northern Leopard Frog (Rana pipiens) had the highest site occupancy, occurring at five of seven sites, followed by the Woodhouses Toad (Bufo woodhousii) which was detected most often in 2011, and Boreal Chorus Frog (Pseudacris maculata) recorded at four and three sites, respectively. The Boreal Chorus Frog was detected vocally calling at two sites during the spring visits with tadpoles at the Tenmile Creek site and two adult incidental sightings during summer visits. We also recorded four reptile species (in order of site occurrence) Painted Turtle (Chrysemys picta), Western Rattlesnake (Crotalus viridis), Snapping Turtle (Chelydra serpentina) (MT SOC) and Terrestrial Garter Snake (Thamnophis elegans). We observed the presence of juvenile snapping turtles during the spring site visit at Trusslers (Otter JT) indicating successful overwintering of 2011 hatchlings. Conclusions. Similar patterns of aquatic community species and biotic integrity were documented between the 2012 and 2011 surveys, despite significantly different flow regimes. Biotic integrity of mainstem Otter Creek (based on fish) in the upstream control reach remains higher and decreases as you proceed downstream with slight improvements in the IBI of the impact and downstream sites since 2011. Macroinvertebrates show no discernible pattern of integrity spatially, but temporally are showing higher integrity scores during the summer months. Fish communities have reassembled themselves since the 2011 high water with the addition of a new introduced species to three sites in 2012, likely from stock pond overflows, and sand shiners are no longer being collected at the Otter 2 impact site. The extraordinarily high density and large biomass of fish in the reach below Truslers Ranch road crossing, essentially stacking up downstream of this barrier (20,000 fish per 300 m) has dispersed to other sections of Otter Creek and now averages about 3,000 fish per 300m with far fewer density dependent fish anomalies (lesions and parasites, i.e., yellow grub an and anchorworm). The fish condition index at this site has improved tremendously since 2011

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