Diet and vertical space use of three sympatric opossums in a Brazilian Atlantic forest reserve

Abstract

Few studies have investigated the ecological relationships between marsupials or their importance in community composition (Dickman 1984). The small size, nocturnal activity and arboreal habits of many species of didelphid marsupials present some difficulties in studying them. Vertical space use of vertebrates in tropical forests is difficult to examine, especially because of canopy height and great habitat complexity (sensu August 1983). However, this latter factor has a considerable importance in spatial separation of sympatric species, amplifying the possibilities of resource partitioning (Giller 1984). Previous studies on vertical space use of didelphid marsupials showed the importance of vertical stratification for this group (Charles-Dominique et al. 1981, Julien-Laferriere 1991, Malcolm 1991, Stallings 1989). Miles et al. (1981) stated that ecological segregation of Neotropical marsupials is not obviously determined by the species' diets, but is better related to spatial differentiation, which discards competition for food. However, these authors recognize the necessity to study the interactions between diet and space use for the comprehension of resource partitioning strategies. The purpose of this study was to examine the food habits and vertical space use in sympatric species of opossums in the Atlantic forest of Brazil. We hypo-