Biogeographic regions of Central Argentina based on snake distribution: evaluating two different methodological approaches

Abstract

Regionalization studies attempt to divide an area into regions by studying the distribution of its biota. Here we used snake distribution in Central Argentina to recognize distribution patterns, and then compared two methods (cluster analysis and endemism analysis) and the patterns found with previously defined regions. Both analyses recovered Chaco and, within Chaco, the subregion Chaco Serrano, as well as all the snake species that are threatened or range-restricted occurring only in the Chaco region, which has been severely deforested in the last decades. The Espinal region was not recovered by cluster analysis or NDM software, and may be considered an “impoverished” Chaco or a transition zone. The Pampas was only recovered by cluster analysis. NDM appears to be more robust than cluster analysis, whereas the latter seems to be very sensitive to sampling problems, sometimes identifying spurious areas or areas characterized by having no exclusive species.

Keywords:

• biogeographic areas
• conservation
• regionalization studies
• snake distribution

Acknowledgements

The authors thank Julián Lescano, Ernesto Verga, Sebastián Quinteros, Nicolás Pelegrin and Paola Carrasco for their support and friendship; Jorgelina Brasca greatly improved the English and two anonymous reviewers made suggestions that improved our manuscript. This work was funded by SECyT-UNC (214/10) through a grant to G. Leynaud and by CIUNSa (Consejo de Investigaciones de la Universidad Nacional de Salta).