Diversity of rodents in three altitudinal zones in Cloudbridge Nature Reserve, Costa Rica

Abstract

Elevation is a natural gradient that shapes wildlife and vegetation communities. Therefore, spatial, climatic and ecological hypotheses have been proposed to describe the diversity of rodents in the altitudinal gradient. Our objective was to describe the biological diversity of rodents at three elevations in relation to microhabitat characteristics and seasonality. We captured rodents using Sherman traps in three altitudinal zones (1600, 1800, 2000 m.a.s.l.) during the dry and rainy season. We measured five microhabitat characteristics at each elevation. We compared the species diversity using coverage-based rarefaction and extrapolation curves and the composition of the rodent’s community using the similarity indices of Jaccard and Bray – Curtis. In addition, we identify the species that contributed most to the differences in the community. Through Generalized Linear Models (GLM) we evaluate 1) the rodent occurrence by elevation, seasonality and microhabitat characteristics and 2) the variation of microhabitat characteristics by elevation and seasonality. In 2100 night-trap effort we captured 200 individuals of nine species. The most abundant species was Peromyscus nudipes. We found that the species diversity decreases with elevation and in the dry season. In terms of species composition, the low elevation between seasons and the high elevation between seasons were more similar. However, when we analyze the abundance, the 2000 m elevation were more similar between seasons. Rodent occurrence depends on the elevation. Finally, the microhabitat characteristics vary by elevation and seasonality. In conclusion, at Cloudbridge Nature Reserve the elevation influences the diversity and the presence of rodents by changing the microhabitat characteristics. Therefore, sites with microhabitat characteristics that could provide protection against predators and potential food sources harbor more rodent diversity.