Interactions between aroids and arboreal mammals in the Brazilian Atlantic rainforest

Abstract

The Brazilian Atlantic rainforest harbours at least 129 non-volant mammal species. There is also a diverse and numerous epiphytic flora associated with this Neotropical rainforest, including several species of Araceae. Nevertheless, knowledge of the ecology of this group of plants and its interaction with animals is poor. In this study we investigated the interactions between epiphytic aroids and arboreal mammals in the Atlantic forest. We carried out the field work between November 1995 and June 1997 in the Parque Estadual Intervales, southeastern Brazil, a still well preserved forest area of approximately 490 km2. We analysed faecal samples from primates (Cebus apella and Brachyteles arachnoides), collected during observations in the field, and marsupials (Didelphis aurita, Micoureus demerarae, Gracilinanus microtarsus), collected from animals captured monthly or bi-monthly in livetraps. We recorded 17 species of Araceae in the study area. The seeds of eight species occurred in the faecal samples: Anthurium harrissi, Monstera adansonii, Philodendron corcovadense, P. appendiculatum, P. exymium, P. crassinervium, P. obliquifolium, and Heteropsis oblongifolia. Aroids were present in faecal samples of the primates during most of the year, with a mean monthly percentage of occurrence of about 56.2%. For marsupials, aroids also were a seasonally important food source, as between November and June the mean monthly percentage of occurrence in faecal samples was about 26.5%. Our data indicate that aroids are an important food source for arboreal and semi-arboreal mammals and that these animals may play an important role as seed dispersers of this group. Aroids and arboreal mammals appear to interact more strongly in Atlantic forest than in other Neotropical forests.