We study how interactions between animals and plants influence the ecology and evolution of animal and plant traits, including herding behavior in peccaries and fruit structure in palms. Through collaborative work we have described the way in which fruits parts and seed number may have evolved in Attalea palms in response to opposing predation pressures from vertebrate dispersers and vertebrate and invertebrate predators. Tapirs, white-lipped peccaries, collared peccaries, tortoises and other animal species and how these interact to influence the diversity, organization and structure of an Amazonian forest through seed dispersal and seed and seedling predation. We also consider the influence of seed-eating insects in the system and examine how organisms acting at different trophic levels influence ecological and evolutionary outcomes. For example, we noted how interactions between tapirs, peccaries, rodents, primates, ants, bruchid beetles and palms generated distribution and abundance patterns for all species, and influenced ecological and evolutionary patterns. Past funding by World Wildlife Fund Canada, Wildlife Conservation Society, World Wildlife Fund-USA, Scott Neotropical Fund, and the University of Florida.
Structure and heterogeneity of landscapes of the SESC Ecological Reserve, Pantanal, Mato Groso, Brazil: effects on mammalian species richness and population density (Current).
With de Oliveira L.F. (PI) National Museum of Brazil, Rio de Janeiro, Cordeiro J.L.P. Fundação Oswaldo Cruz (FioCruz), Rio de Janeiro, Hoffman G.S., Federal University of Rio Grande do Sul (UFRGS), Haseneck H., UFRGS, de Andreazzi C.S., FioCruz, Baztazini V., UFRGS and Sicuro F.L., Universidade Estadual do Rio de Janeiro, Rio de Janeiro and Fragoso J.M.V. Funded by SESC-Brasil.
We use vertebrate exclosures in the Pantanal wetlands of Brazil to assess interactions between seed and seedling consumers and palm species distributions patterns. This information is linked to palm species aggregation and distribution patterns mapped using remote sensing and ArcView. We are describing how these interactions contribute to large-scale pattern generation in palm trees.
Under development: With E Kurten and R. Dirzo (Stanford University). Does defaunation decrease plant diversity in a Neotropical forest landscape? Submitted to NSF
This project addresses a fundamental and salient biodiversity question: What are the mechanisms by which plant diversity declines as a consequence of vertebrate species loss in tropical forests? The variation in plant diversity responses to the loss of vertebrate interaction partners is poorly understood. Yet, understanding how the effects of defaunation propagate to the plant community is increasingly important as over-hunting affects more tropical forests worldwide. Theory suggests that seed dispersal failure may lead to local extirpation of some plant species. Empirical data also suggest that some species may benefit from reduced vertebrate herbivore pressure, leading to increases in plant species dominance and exclusion of competitors. Both patterns suggest that plant diversity may decline as a result of defaunation. However, current data is insufficient for identifying consistent plant responses to defaunation and elucidating the relevant underlying drivers.