R Code for Bison Climate Envelope Model

This file contains the R code to run the climate envelope model for Bison in North America and project the predicted suitability for bison on current climate and four future intervals extending to the year 2100. The code will also calculate area size of suitability for selected thresholds, calculate centroids of the area, distance moved by the centroids between intervals and significant shifts between intervals for suitability score distributions.