Frugivory and Seed Dispersal by the Lowland Tapir (Tapirus terrestris) in Southeast Brazil 1

SEED DISPEKSAL REPRESENI'S T H E LAST PHASE of a plant's reproductive cycle, and is therefore critical for regeneration (Janzen 1970, Chapman & Chapman 1995). Birds and mammals are the most important vertebrate seed dispersers in the Neotropics (Jordano 200 1). This relationship between vertebrates and fruiting plants is so important that in some tropical areas cu 90 percent of tree species are dispersed by vertebrates (Opler et al. 1980, Galetti 1996, Jordano 2001). Among mammalian dispersers, ungulates are particularly important because they can distribute great quantities of seeds (Janzen 1981, Bodmer 1991, Miller 1996, Olmos 1997, Fragoso & Huffman 2000) and move them long distances (Fragoso 1997). Tapirs ( Tapirus spp., Perissodactyla, Tapiridae) are the only remaining species of Pleistocene megafauna in South and Central America (Simpson 1980, Eisenberg 1981). Studies on frugivory and seed dispersal by tapirs have been conducted at several Neotropical sites (Bodmer 1990, Rodrigues et al. 1993, Salas & Fuller 1996, Fragoso 1997, Olmos 1997, Fragoso & Huffman 2000, Henry et al. 2000) but are lacking from semi-deciduous forests of South America. Tapirs disperse large-seeded species, especially palms (Bodmer 1990, 199 1 ; Fragoso 1997); yet they may not be efficient seed dispersers (sensu Schupp 1993). In fact, they digest many seeds and generally defecate in areas not favorable for the establishment of seedlings (e.g., water channels; Janzen 1981a, Salas & Fuller 1996). In addition, they typically defecate large quantities of seeds in a single place, thus causing high competition among seedlings (Howe 1990) or facilitating location by seed predators (Chapman 1989, Fragoso 1997). In the semi-deciduous forests of Slo Paulo, Brazil, few areas support viable tapir populations (Morro do Diabo State Park and Ecological Station of Caetetus; Cullen et al. 2000). Although not considered threatened, the lowland tapir Tapirus terrestris is vulnerable to hunting and habitat fragmentation and often faces local extinction in small or overhunted forest patches (Chiarello 1999, Cullen et al. 2000). For this reason, it is essential to understand the role of tapirs as seed dispersers (especially for large-seeded species) in maintaining plant species diversity (Fragoso & Huffman 2000). We evaluated the use of fruits by the lowland tapir and its role as a seed disperser in a semi-deciduous forest fragment in southeast Brazil. The Esta+o Ecol6gica de Caetetus (E. E. Caetetus; 22"27'S, 49'43'W) is a 2,100 ha forest fragment located between Gdia and Alvinlandia, Sio Paulo, Brazil. This area is considered a semi-decidous tropical forest and was once an extension of the coastal Atlantic Forest. During the dry season there is a partial leaf fall in some tree species (Leitzo-Filho & Morellato 1997). Annual rainfall is cu 1480 mm. Vegetation in the area constitutes a mosaic of at least four different habitats: primary forest (49%); second growth (edge and bamboo; 13%); palmito (Euterpe edulis) stands (1%); and swamp areas (2%; Keuroghlian, pers. obs.). The arboreal flora is rich with Lauraceae, Myrtaceae, and Rubiaceae species (Durigan et al. 2000). The non-volant, medium-sized mammal fauna is relatively well preserved. It includes three primates species (Leontopithecus chrysopygus, Cebus apella, and Alouatta j k c a ) , two peccary species ( Ejacu pecari and T tajacu), tayra (Eiru barbara), coati (Nasua nasua), paca (Agoutipaca), and deer (Mamma spp.; Keuroghlian 1990). The frugivorous diet of the tapirs was sampled by collecting feces encountered during mammal censuses in the area. Different trails, ranging from 1 to 8 km, were walked 13 days each month between January 1994 and April 1999. Fecal samples were found in numerous piles together (latrines), individually in dry areas, or near the forest edge and in streams. Each fecal sample was collected, placed in a paper bag, numbered, and dried in an oven at 55°C.