Effects of regional context and landscape composition on diversity and composition of small rodent assemblages in Argentinian temperate grasslands and wetlands

MASSA, C.; TETA, P.; CUETO, G. R.

MAMMALIA

WALTER DE GRUYTER & CO

Lugar: Paris; Año: 2014 vol. 78 p. 371 - 382

0025-1461

This study aims to describe landscape evolution along two contiguous ecoregions with different land use intensity to assess changes in small mammal?s communities. Rodent remains in pellet samples of Barn Owl, were used to estimate the attributes of rodent assemblages. Two major biomes were considered in this study, a mosaic of wetlands (Delta and Paraná Islands ecoregion) and a mosaic of grasslands and cultivated fields (Pampa ecorregion). Environmental characterization was based on the analysis of satellite images and weather data. Fourteen rodent species in 28 sampling sites were identified, totalizing 7645 prey items. Linear combinations of variables that characterized the landscape explained 66.6% of variation in the composition of rodent assemblages. A positive linear relationship between rodent diversity and the number of different patches was found in the Pampa. Our results suggest that, at landscape scale, disturbances caused by agricultural intensification would be favoring the increase of representativeness of generalist and competitively subordinated species. In turn, changes in rodent diversity at the Paraná Delta were negatively associated with the percentage of water-covered area and the number of patches. The hydrological regime of this ecoregion acts as a filter for species establishment restricting the richness of the rodent assemblages.