Supplement 1. R script for calculating the Raup-Crick metric as described in the text.

File List Raup-Crick.txt -- (MD5: c37b2472e568eae3f1c0a5f1adec3d80) Description The code included in Raup-Crick.txt allows one to perform the null model analyses described in the text. The resulting values represent the degree to which observed numbers of shared species between any two sites differ from what would have been expected by random chance given the number of species co-occurring in each of two localities, and the designated regional species pool.