Figure 2. Response curves of P. americana (top) and P. pennsylvanica (bottom) to their strongest respective predictors. Red indicates the mean response averaged over the 10 replicate MAXENT runs, while blue indicates one standard deviation. For P. americana, BIO15 (Precipitation Seasonality) had the largest percent contribution, while BIO3 (Isothermality) had the largest permutation importance. For P. pennsylvanica, BIO17 (Precipitation of the Driest Quarter) had the largest percent contribution, and BIO11 (Mean Temperature of the Coldest Quarter) had the largest permutation importance.