Fig. 2.

Increase in Fisher’s alpha with (A) increasing numbers of locations (average of 50 replicates per region with random input order of locations), i.e., regional diversity, and (B) increasing distance around locations (based on 50 replicates per region each with a randomly selected starting location), i.e., species turnover. Error bars indicate SD among location reorderings. Fisher’s alpha can decline if the number of stems added to the sample increases disproportionally to the number of new species detected.