Removal of palm fruits and ecosystem engineering in palm stands by white-lipped peccaries (Tayassu pecari) and other frugivores in an isolated Atlantic Forest fragment

Long-term studies in a 2,178 ha fragment of semideciduous Atlantic Forest demonstrated important interactions between white-lipped peccaries (Tayassu pecari) and the common palms, Syagrus romanzoffiana and Euterpe edulis. We conducted fruit removal and medium-to-large-sized mammalian exclusion experiments to: (1) quantify seasonal fruit consumption from high-density patches beneath parent trees by T. pecari and other consumers, and (2) measure impacts of T. pecari rooting and foraging activities on seedling dynamics in E. edulis stands. A diverse array of fauna consumed S. romanzoffiana fruits. During the dry season, when S. romanzoffiana palms provided 68% of fruit dry weight in the fragment, T. pecari consumed significantly greater amounts than other consumers, and along with Pecari tajacu and Tapirus terrestris, were potential seed dispersers. The rodents, Sciurus ingrami and Agouti paca, consumed most S. romanzoffiana fruits in the wet season, acting as both seed dispersers and predators. More than 95% of E. edulis fruit removal was due to seed predation by T. pecari. Intense removal during the dry season was closely linked with previously documented range shifts and habitat preferences by T. pecari. Exclusion plot experiments in E. edulis (palmito) stands showed that the number and proportion of nonpalmito (not E. edulis) seedlings increased dramatically in the absence of T. pecari rooting and foraging activities that disturbed soil and thinned seedlings. We discuss the importance of these ecosystem engineering activities and palm-peccary trophic interactions for long-term maintenance of E. edulis stands and T. pecari populations, as well as water balance, in the forest fragment.