Scale analysis of carabids richness (Coleoptera: Carabidae) in southern South America

Abstract

The southern South America presents a complex history of geomorphological and climatic events, which have modulated and fragmented the southwestern part of the Andes mostly. Given the complexity of the southern landscape, the analysis of the hierarchical components alpha-?, beta-? and gamma-? on carabid diversity allows exploring the responses of species to spatial changes patterns according to the scales of the landscape. In order to understand how spatial scales influence the carabid diversity in southern South America, we used an approach at multiple spatial scales of multiplicative diversity partitioning. We included four spatial scales in our analysis: among 0.25° quadrats, 0.5° quadrats, provinces and biogeographic sub-regions. The results showed that the pattern of carabid distribution is not random, and varies according to the spatial scale. At larger scales ?-diversities are observed to be higher than expected, but lower than expected at smaller scales. This suggests that carabid ensembles are more homogenous than expected, particularly at the scale of 0.5° quadrats. As explanatory factors, glacial/post-glacial events and historical processes may have had an impact on the present species patterns. Furthermore, due to the importance of beta-? diversity on local and regional scales, a promising approach for future studies is to investigate which biogeographic mechanisms seem to determine the species distribution in different provinces.