Vertebrates play a fundamental role in the dispersal of Neotropical trees, generating different seed shadows according to their physical and behavioral features. Tapirs are capable of consuming great quantities of large fruits, and they defecate seeds far from parent trees. For instance, intact seeds of the palm Syagrus romanzoffiana have been found in tapir dung piles in the Atlantic Forest of southeastern Brazil, suggesting that tapirs effectively disperse this species. However, recruitment was not examined therein. We studied tapir endozoochory of large and medium seeds in the semi-deciduous Atlantic Forest of Argentina by examining dung piles found within Iguazu National Park. We recorded dung-pile positions to evaluate the spatial distribution. We also counted the number of juveniles in 2 Â 2 m quadrats placed on old dung piles in latrines, beneath adults and in random sites to estimate recruitment levels. Syagrus romanzoffiana seeds were present in 98 percent of dung piles, averaging 4 200 seeds/dung pile, indicating that this species constitutes the main fruit component in the tapir's diet. Dung piles showed a clumped deposition pattern reflecting the use of latrines. Juvenile recruitment in latrines was 21 times higher than that of under-adult sites and 500 times greater than in random sites, and correlated with the frequency of use of the areas. We concluded that the lowland tapir is a major disperser of S. romanzoffiana. Given that this palm can be considered a keystone species, a disruption of this interaction might affect the entire community of frugivores in the long term.Abstract in Spanish is available at http://www.blackwell-synergy.com/loi/btp.

Hunting pressure, fragmentation and deforestation have caused global declines in animal abundance, and the consequences for plant communities are poorly understood. Many large-seeded plants, for instance, depend on large and endangered vertebrates for seed dispersal. In some Semi-deciduous Atlantic Forests, endangered tapirs (Tapirus terrestris) are major dispersers of pind o palms (Syagrus romanzoffiana). Here, we compare recruitment patterns of pind o palms between protected and disturbed (defaunated) Atlantic Forest areas in Argentina and evaluate the potential consequences of the lack of the main disperser for pind o palm regeneration. We analyzed the number and spatial pattern of pind o adults, offspring, and tapir dung piles within ten plots established in an area spanning tapir latrines inside Iguaz u National Park and in a fragmented forest area outside the park where tapir is locally extinct. In both areas, we evaluated recruitment levels beneath 24 adult palms in circular plots centered on adult stems. We found lower pind o palm recruitment outside the park where offspring tended to be aggregated around adult palms. In contrast, in Iguaz u National Park offspring were spatially associated with tapir dung-piles, in which most offspring were registered. Recruitment under adults was higher outside the park suggesting a lower rate of seed removal in disturbed areas. Our results show that tapir dispersal promotes higher recruitment levels of pind o offspring and shapes their spatial pattern, breaking the spatial association with adult (presumably maternal) palms. These results are useful for predicting the impact of local tapir extinction on this palm.Abstract in Spanish is available in the online version of this article.