Small mammal community in the largest urban forest in the Americas, southeastern Brazil

Human activities directly influence the diversity, abundance and distribution of species. The loss of species in forested areas-called the defaunation process-is an outcome of anthropogenic processes, especially in forest remnants close to urban and rural areas. The aim of this study was to evaluate small mammal diversity in a forest-urban interface area at the largest urban forest in the Americas, in the city of Rio de Janeiro, Brazil. Seven small mammal species were captured: the marsupials Didelphis aurita, Marmosa paraguayana, Metachirus myosuros, and Monodelphis americana; and the rodents Akodon cursor, Oligoryzomys nigripes, and Trinomys dimidiatus. The common opossum D. aurita was dominant in the community. Beta diversity indices revealed little variation among types of environments and over time. Species richness of the small mammal community in the study area was lower than that reported in the literature. The study area contained a fixed set of core species in the community over time and among environments (peridomicile, disturbed forest, and preserved forest), with the presence of less abundant species in some periods and environments. Small mammal species richness observed was lower than in preserved areas, when compared with other studies. Historical, ecological, and anthropogenic characteristics of the area may have contributed to its low diversity.