From dropping to dropping: The contribution of a small primate to seed dispersal in Atlantic Forest

The dynamic interaction between animals and plants through frugivory and seed dispersal is one of several ecological processes that modulates tropical biodiversity. Here we evaluated the potential role of a highly-frugivorous Neotropical primate, the black-fronted titi monkey (Callicebus nigrifrons), as seed disperser. We studied two titi monkey groups in semideciduous Atlantic Forest remnants. Each group fed on over 49 zoochorous plant species in about one year and ingested seeds from nearly a half of them, especially those with small seeds (<0.5 cm). The groups of titi monkeys defecated a large number of seeds, reaching over 300 seeds per day (1-305). More than half of the total deposited seeds and seed species germinated after gut passage, however gut passage reduced germination success in three of five evaluated species. Feces were deposited in small clumps distributed across groups' home range. We suggest that the observed distribution pattern of feces may enhance plant reproductive fitness by increasing the probability of seeds being deposited far from parent plants, in novel and favorable sites. We concluded that the seed handling and deposition behavior of black-fronted titi monkey make this primate an important agent for Atlantic forest regeneration.