Fig. 2.

Jackknife tests were used to estimate variable importance based on the drop in AUC when excluding each variable in turn as well as models including only single variables. Decreases in AUC when variables are excluded (dark bars) indicate that unique information is contained in a variable that is not present in other variables. Models using land cover as the only variable have the largest AUC, demonstrating that land cover has the most useful information when used alone, as indicated by the large light-colored bar. GAP = United States Geological Service, National Gap Analysis Program (GAP) National Vegetation Classification—formation or land use classification, BIO16 = precipitation of the warmest quarter, BIO19 = precipitation of the coldest quarter, BIO2 = mean diurnal range (mean of monthly (maximum temperature – min temperature)), BIO5 = maximum temperature of the warmest month, BIO7 = annual temperature range, ELV = elevation.