Modelling of historical stonefly distributions using museum specimens

Stoneflies are imperiled in many regions of the world, but it is often difficult to determine their relative imperilment because of the absence of reliable data. Natural history collections, such as those at the Illinois Natural History Survey (INHS), are sources for such data. We have used Random Forests models of the historical distributions of Illinois stoneflies to better understand their natural range. We have also determined which of 58 georeferenced reach, watershed, and climate Summary data appear to explain these distributions. Four species were modelled with relative success, suggesting that this approach has merit and that it may be useful for determining the extent of loss and to informing future conservation efforts for Plecoptera in Illinois and surrounding areas. Expanding the range of this analysis to include adjacent states will improve the models and allow us to model rare species for which enough data were not present from Illinois alone.