Effects of palm heart harvesting on avian frugivores in the Atlantic rain forest of Brazil.
Abstract
The effects of harvesting the dominant palm tree Euterpe edulis on the abundance of 15 large frugivorous birds (Ramphastidae, Cracidae, Cotingidae, Trogonidae and Psittacidae) were studied over 2 years (1993-95) at the Parque Estadual Intervales in the Atlantic forest of Brazil. Abundance was estimated using unlimited distance point counts (IPA) and encounter rates. Although all the bird species studied were known to eat Euterpe fruits, only one Cotingidae (Carpornis melanocephalus) and one Ramphastidae (Ramphastos vitellinus) were negatively affected by the removal of this palm from the forest. It is suggested that Euterpe palms in the lowland forests do not fulfil the role of keystone species because they bear ripe fruits during the period of peak overall fruit availability and because birds may switch their diets to other food sources when palms are removed. In conclusion, E. edulis exploitation is not recommended in small forest areas, nor in areas where E. edulis bears fruit during the period of overall fruit scarcity.