Fragmentation effects on population density of three rodent species in secondary Atlantic Rainforest, Brazil

Abstract

We investigated the population density of the two common rodent species Akodon montensis, Oligoryzomys nigripes, and the more specialized endemic Delomys sublineatus in secondary forest fragments of the highly endangered coastal Atlantic Rainforest. Linear regression was used to examine relationships between population density and four landscape variables. We tested the hypothesis that rare species, which are more affected by fragmentation than the common species, should decrease in population density with decreasing fragment size while the density of common generalist species should be unaffected or increase in smaller fragments. The results revealed that A. montensis and O. nigripes showed no significant association to any landscape variable. The density of D. sublineatus showed a strong tendency to a positive correlation to fragment size as well as a negative correlation to edge density. The results underline the importance of large and connected forest remnants in the Atlantic Rainforest to guarantee an effective protection of endemic small mammal species.

Keywords:

• Akodon montensis
• Brazil
• Delomys sublineatus
• fragmentation effects
• Mata Atlântica
• Oligoryzomys nigripes

Acknowledgments

We thank our Brazilian counterparts Renata Pardini and Jean‐Paul Metzger for providing the landscape variables as well as Fabiana Umetsu (all University of São Paulo). We thank Christoph Knogge and Klaus Henle (UFZ Leipzig) for very fruitful cooperation and scientific and logistic support. We also would like to thank Jörg U. Ganzhorn for supporting this study and helpful comments on statistical questions. We are grateful to all field assistants. An anonymous referee provided helpful comments on an earlier version of this manuscript. We appreciate the financial support provided by the BMBF Germany (German Federal Ministry of Education and Research, project ID: 01 LB 0202). This study is part of the BIOCASP project (Biodiversity conservation in fragmented landscapes on the Atlantic Plateau of São Paulo, Brazil).