Abstract

MAGNUS, Luíza Z  and  CACERES, Nilton C. Effects of area size on the species richness and composition of small mammals in the Atlantic Forest of Brazil. Mastozool. neotrop. [online]. 2012, vol.19, n.2, pp.163-178. ISSN 0327-9383.

The Atlantic Forest is one of the main biomes of Brazil, but it is threatened by the land use. The study aimed to analyze the effects of area size and conservation on the species richness of small mammals (rodents and marsupials) in the biome. It also analyzes if there is a directional pattern of species loss from species-rich communities to those poor in species. We carried out a literature review on small-mammal species composition in different areas of the Atlantic Forest, generating a database containing information about fragment size, conservation status, and species richness and composition. Rodent abundance showed a positive correlation with the area size whereas there was also a correlation between the proportion of forest dwelling rodents and the degree of conservation. The composition of all species and that of rodents revealed as nested subset with NODF = 23.69 and 24.73 respectively (P < 0.001). Forest fragmentation affects mainly rodents, just in relation to area size and degree of conservation. This highlights the importance of correct preservation of the Atlantic Forest, taking into account that some species are vulnerable to extinction. Small rodents are a comprehensive part of the Atlantic Forest diversity, being bioindicators in this biome, while we highlight the fragility of this mammal group by the habitat loss caused by the severe fragmentation rate of the biome.

Keywords : Cricetid rodents; Forest dwelling species; Marsupials; Nestedness subsets; Species-area relationship.

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