ABSTRACT

Rodents and marsupials together, form the most rich group of mammals in Brazil, they are distributed in all biomes, including Atlantic Forest, and can be used to analyze environmental quality. The Araucaria Forest is a threatened formation of the Atlantic forest with few areas remaining intact and a huge lack of knowledge about the potential of its secondary forest fragments to act as habitat refuges to native fauna. This study evaluated the species richness and diversity of non-volant small mammals among five vegetation types within a protected area in an Araucaria Forest area from southern Brazil. The sampling was made in six bimonthly campaigns during a year, by pitfall and live traps. This effort resulted in 875 captures of 625 individuals from 16 species. The most common species in Pine Plantation was Oligoryzomys nigripes, in Natural Regeneration forest was Thaptomys nigrita and Akodon montensis was most often captured in the other vegetation. Although differences in species composition were found among the different vegetation types, there was no significant difference in species richness. Nevertheless, true diversity values were significantly lower in the Pine Plantation. The results demonstrated that the substitution of native for exotic vegetation generated a negative impact on the group diversity. More studies, in other Araucaria Forest areas are necessary to allow better understanding of the processes driving this loss of diversity in this biome threatened by antropic action.

KEYWORDS
Didelphimorphia; Mixed Rain Forest; Sigmodontinae; species composition