Seed dispersal patterns produced by white-faced monkeys: implications for the dispersal limitation of neotropical tree species

1 Primate frugivores are important seed dispersers for a large fraction of tree species in many tropical forests. The movement, diet preferences and defecation patterns produced by primates may therefore strongly influence seed dispersion patterns and seedling recruitment success. Here we examine the pattern of seed dispersal generated by white-faced monkeys (Cebus capucinus ) in relation to adult tree distribution in the 50-ha plot on Barro Colorado Island (BCI), Panama. 2 Diet breadth of Cebus was remarkably wide. Over four months they consumed fruits of 95 out of an estimated 240 species available. Seeds of 67 species passed intact through the gut and 28 were spat out. 3 Dispersal effectiveness of Cebus was also high. Two Cebus groups on average spent < 10 min feeding in individual trees, had large home ranges (> 150 ha), travelled 1-3 km day(-1) and defecated seeds in small clumps throughout the day. 4 Mean dispersal distance of ingested seeds was 216 m (range 20-844 m), with the highest probability of dispersal 100-200 m from the parent plant. For six of nine species studied, the distance between defecation sites and nearest conspecific adults of seeds in faeces was not significantly different from random expectations. 5 The scattered dispersal pattern produced by Cebus suggests that this species contributes relatively little to dispersal limitation (sensu Nathan & Muller-Landau 2000) compared to other dispersers in the community. Long-distance dispersal by Cebus resulted in substantial movement of seeds in and out of the 50 ha plot, and suggests that inverse modelling procedures to estimate dispersal functions from trap data may not adequately describe dispersal patterns generated by this primate.