Small Non-Volant Mammals of an Ecotone Region between the Cerrado Hotspot and the Amazonian Rainforest, with Comments on Their Taxonomy and Distribution

Araguaia National Park is located on Bananal I., Tocantins state, Brazil. This conservation unit exists in the transitional area between Cerrado, a tropical savanna hotspot, and Amazonian biomes. Transitional zones are thought to be characterized by high species richness due to the overlap of species distributional ranges, and by a high level of endemism provided by the uniqueness of these regions. The aim of this study was to survey small non-volant mammals and analyze the species composition, richness, and endemism in order to test the above hypotheses, and to contribute to the increasing knowledge of the mammalian fauna of the Cerrado, since the northern portion of this biome is one of the most poorly known. We surveyed marsupials and small rodents using both live and pitfall traps with total trapping efforts of 2259 live trap-nights and 3200 pitfall trap-nights. We found that typical inhabitants of the Cerrado biome occurred side by side with species commonly distributed in the Amazonian rainforest, in addition to the presence of 2 regionally endemic rodents. Nevertheless, the low species richness (13 species) and percentage of endemics surveyed demonstrate that Bananal I. presents some special characteristics, such as climate seasonally and periodic inundation, which may have influenced the small non-volant mammal community richness and composition, which need to be further studied.