Responses of five small mammal species to micro-scale variations in vegetation structure in secondary Atlantic Forest remnants, Brazil

Although vegetation structure differed among fragments, micro-scale distribution of most of the species was influenced by vegetation structure in a similar way in different fragments. Among the three species that were previously shown not to be vulnerable to forest fragmentation, A. montensis and G. microtarsus were present at locations with an open canopy and the occurrence of O. nigripes was associated to a low canopy and a dense understory. On the other hand, from the two species that were shown to be vulnerable to fragmentation, M. incanus was captured most often at locations with a closed canopy while the distribution of D. sublineatus was not clearly influenced by micro-scale variation in vegetation structure.Results indicate the importance of micro-scale variation in vegetation structure for the distribution of small mammal species in secondary forest fragments. Species that are not vulnerable to fragmentation occurred at locations with vegetation characteristics of more disturbed forest, while one of the species vulnerable to fragmentation was found at locations with older forest characteristics. Results suggest that micro-habitat preferences may be an important factor influencing the capacity of small mammals to occupy altered habitats and, consequently, their vulnerability to forest fragmentation at a larger spatial scale.The coastal Atlantic Forest is one of the most diverse, and most threatened, natural environments in the world [1]. Due to severe human impact over the last few centuries most of the primary coastal Atlantic Forest has been destroyed. Only 7% of its original extent remains [1] and a considerable part of remaining forest takes the form of secondary forest fragments at different stages of regeneration, embedded in a rural or urban matrix [2,3]. In fragmented landscapes such as these, both the stage of regeneration and the degree of fragmentation influence forest structure within the fragments, which in turn determines habitat suitability an