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The Scientific World Journal
Volume 2012, Article ID 819328, 13 pages
http://dx.doi.org/10.1100/2012/819328
Research Article

Geographical Gradients in Argentinean Terrestrial Mammal Species Richness and Their Environmental Correlates

1Biogeography, Diversity, and Conservation Research Team, Department of Animal Biology, Faculty of Sciences, University of Malaga, 29071 Malaga, Spain
2Departamento de Ciencias Naturales, Facultad de Ciencias, Universidad Nacional de La Pampa, Avenida Uruguay 151, Santa Rosa 6300, Argentina
3Instituto de Ecología y Ciencias Ambientales (IECA), Facultad de Ciencias, Universidad de la República, Iguá 4225, esq. Mataojo, Montevideo 11400, Uruguay
4“Rui Nabeiro” Biodiversity Chair, CIBIO, University of Évora, 7000-890 Évora, Portugal
5Division of Biology, Imperial College London, Silwood Park Campus, Ascot, Berkshire SL5 7PY, UK

Received 16 May 2012; Accepted 10 June 2012

Academic Editors: H. H. Basibuyuk and S. Giokas

Copyright © 2012 Ana L. Márquez et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We analysed the main geographical trends of terrestrial mammal species richness (SR) in Argentina, assessing how broad-scale environmental variation (defined by climatic and topographic variables) and the spatial form of the country (defined by spatial filters based on spatial eigenvector mapping (SEVM)) influence the kinds and the numbers of mammal species along these geographical trends. We also evaluated if there are pure geographical trends not accounted for by the environmental or spatial factors. The environmental variables and spatial filters that simultaneously correlated with the geographical variables and SR were considered potential causes of the geographic trends. We performed partial correlations between SR and the geographical variables, maintaining the selected explanatory variables statistically constant, to determine if SR was fully explained by them or if a significant residual geographic pattern remained. All groups and subgroups presented a latitudinal gradient not attributable to the spatial form of the country. Most of these trends were not explained by climate. We used a variation partitioning procedure to quantify the pure geographic trend (PGT) that remained unaccounted for. The PGT was larger for latitudinal than for longitudinal gradients. This suggests that historical or purely geographical causes may also be relevant drivers of these geographical gradients in mammal diversity.