CONICET | Buscador de Institutos y Recursos Humanos

The sigmodontine rodent Pseudoryzomys simplex inhabits humid environments of tropical and subtropical lowlands of southeastern Perú, eastern Bolivia, eastern and central Brazil, western Paraguay and northeastern Argentina (Humid Chaco). Fossil record of P. simplex in the Humid Pampas indicated a broader distribution of this oryzomyine during the interval from 4.7 to 0.2 cal ka BP. Originally, the presence of this species in fossil sites was considered an indicative of warmer and possibly more seasonally marked climate. Nonetheless, it has been recently proposed that P. simplex was a typical element of the grasslands of the Humid Pampas, now regionally extirpated due to the intensification of agricultural and livestock activities during the last two centuries. To evaluate this assumption, a new procedure to estimate the Niche of Occurrence in a 3D space was applied to estimate if the Pampean region is an environmentally suitable area for this rodent. As small mammals are closely related to climate and vegetation, 19 bioclimatic variables plus a Potential Natural Vegetation (PNV) layer, without human intervention, were used. Results indicate that the PNV improves the transferability of the models indicating the presence of suitable areas for the species in the Pampean region during current and Late Holocene time periods. Although results suggest that this sigmodontine rodent probably inhabited the Pampean region until human activities became more intense, a better comprehension of the ecological requirements of P. simplex is needed to understand the effect of past and future climate fluctuations. Contribution to projects CGL2016-79334P (Spain), i-COOPB-20287 (CSIC, Spain), and UNLPam 06G (Argentina).

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