Environmental variables.

1: Climate variables was taken from (http://www.worldclim.org/) and calculated from 2.5′ resolution data, 2: (http://glcf.umd.edu/data/gimms/), 3: (http://sedac.ciesin.columbia.edu/wildareas/downloads.jsp), 4: (http://www.gofc-gold.uni-jena.de/wg_biomass/sites/globcover.php), 5: (http://www2.jpl.nasa.gov/srtm/) via worldclim.