Local and regional species richness relationships in viperid snake assemblages from South America: Unsaturated patterns at three different spatial scales

The relationship between local and regional diversity in viperid snake assemblages from South America was estimated. However, viperid species richness was spatially patterned across the continent, and this result can bias significance levels of regression analyses. To overcome this problem, we determined the minimum distance between localities that ensures stochastic independence of diversity estimates across space, using geostatistical analyses. We analyzed the relationship between local and regional diversity at three different spatial scales, by increasing region size. For the three scales, there was a significant linear relationship between local and regional diversity, indicating that local viperid assemblages are unsaturated and that their local diversity is constrained by species richness of the regional pool. Overall, this result indicates the importance of regional and historical processes on the determination of viperid species richness at local scales.