Environmental factors affecting the distribution of three armadillo species (Xenarthra, Dasypodidae) in Argentina

Environmental temperature, rainfall, vegetation structure, soil composition and land use were recognized as relevant factors limiting the distribution of armadillos. The aim of this study was to identify environmental and spatial factors influencing the geographical distribution of the most widespread armadillos occurring in Argentina (Chaetophractus vellerosus, Chaetophractus villosus and Zaedyus pichiy), through the most simple and accurate explanatory modeling. General linear models (GLMs), partitioning analyses of variance and hierarchical partitioning analyses were applied to estimate the species-environment relationships. Climatic variables were recognized as the most relevant factors influencing the three species distribution, consistent with that expected from the hierarchical structure theory in ecological systems. Optimal conditions were mainly arranged in a longitudinal geographic gradient for Chaetophractus species and in a latitudinal-longitudinal gradient for Z. pichiy. The optimal habitat identified for C. vellerosus, larger than previously documented, was characterized by warm, rainy summers and moderately cold, dry winters. The distribution of C. villosus was mainly influenced by temperate conditions of temperature and isothermality, scarcity of rainfall with high seasonality and low aridity conditions, and prevalence of sandy soils. Optimal habitat of Z. pichiy was affected by low temperatures with high seasonality, scarcity of rainfall with aridity conditions and sandy soils.