Characterizing coal and mineral mines as a regional source of stress to stream fish assemblages

To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Elsevier and can be found at: http://www.sciencedirect.com/science/journal/1470160X.Mining impacts on stream systems have historically been studied over small spatial scales, yet\ud investigations over large areas may be useful for characterizing mining as a regional source of stress to\ud stream fishes. The associations between co-occurring stream fish assemblages and densities of various\ud “classes” of mining occurring in the same catchments were tested using threshold analysis. Threshold\ud analysis identifies the point at which fish assemblages change substantially from best available habitat\ud conditions with increasing disturbance. As this occurred over large regions, species comprising\ud fish assemblages were represented by various functional traits as well as other measures of interest to\ud management (characterizing reproductive ecology and life history, habitat preferences, trophic ecology,\ud assemblage diversity and evenness, tolerance to anthropogenic disturbance and state-recognized game\ud species). We used two threshold detection methods: change-point analysis with indicator analysis and\ud piecewise linear regression. We accepted only those thresholds that were highly statistically significant\ud (p ≤ 0.01) for both techniques and overlapped within ≤ 5% error. We found consistent, wedge-shaped\ud declines in multiple fish metrics with increasing levels of mining in catchments, suggesting mines are a\ud regional source of disturbance. Threshold responses were consistent across the three ecoregions\ud occurring at low mine densities. For 47.2% of the significant thresholds, a density of only ≤ 0.01 mines/km²\ud caused a threshold response. In fact, at least 25% of streams in each of our three study ecoregions have\ud mine densities in their catchments with the potential to affect fish assemblages. Compared to other\ud anthropogenic impacts assessed over large areas (agriculture, impervious surface or urban land use),\ud mining had a more pronounced and consistent impact on fish assemblages