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 asse mblages from South America was estimated. However, viperid species richness was spatially patterned across the continent, and this result can bias sig nificance levels of regression analyses. To overcome this problem, we deter mined the minimum distance between localities that ensures stochastic indep endence 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 div ersity, indicating that local viperid assemblages are unsaturated and that their local diversity is constrained by species richness of the regional po ol. Overall, this result indicates the importance of regional and historica l processes on the determination of viperid species richness at local scale s.