Non-volant small mammals at an Atlantic forest area situated nearby a limestone quarry (Limeira quarry), state of São Paulo, Brazil

Response of small mammal species to landscape metrics in a highly fragmented area in the Atlantic forest of southern Brazil

The high rate of destruction of natural habitats has diminished fragments size, which negatively impacts small mammal community species richness and composition. We investigated the abundance of small non-flying mammal species in association with three landscape metrics: the size of the fragment (AREA); the shape index of the fragment (SHAPE); and the size of the central area of the fragment (CORE) in six forest fragments in a highly fragmented landscape of southern Brazil. Three rodent species (Akodon montensis, Oligoryzomys nigripes, Sooretamys angouya) and one marsupial species (Gracilinanus microtarsus) were captured in total. We used generalized linear models to test the influence of the landscape metrics on the abundance of the three most abundant species of small mammals captured (A. montensis, O. nigripes and S. angouya). Among the three species analyzed, A. montensis presented a significant negative association with the metric CORE; O. nigripes and S. angouya presented a positive association with the metric AREA and negative with the metric CORE. The negative association of A. montensis, O. nigripes and S. angouya with the core area of the fragments, and the absence of association of all species with the shape of the fragments indicate that these species might benefit from the effects of habitat fragmentation.

Microhabitat structure and food availability modelling a small mammal assemblage in restored riparian forest remnants

Small mammal populations respond to environmental changes in secondary riparian forest remnants in different ways, depending on the influences of biotic and abiotic variables. The present study evaluated how habitat/microhabitat structure and food availability influence small mammal assemblages in restored riparian forest remnants. Pitfall traps disposed in three linear transects were used to collect small mammals during 9 months of field work. General linear models were built to test the hypothesis that microhabitat structure (litter biomass and type – leaves and branches) and food availability (richness of zoochoric tree species and arthropods) influence species richness and abundance of small mammals. Three hundred and eighty-two individuals belonging to 14 species were captured. Biomass and type of litter (leaves or branches) provided greater structural to microhabitats, allowing the coexistence of morphologically similar species. Besides, food availability influenced foraging strategies of marsupials, forcing them to use the forest floor when zoochoric plants were rare. Thus, litter structure and food availability, allowing spatial segregation of the small mammal species using the forest fragments. We concluded that the maintenance of small mammals and their ecosystem services in restored riparian forests are dependent on habitat structure and food availability, thus, litter and zoochoric plants should be conserved in riparian forest fragments, especially those reforested.