FAPESP-2014/01986-0 - Consecuencias ecológicas de defaunación

Humans are one of the major drivers in structuring vertebrate communities, altering food webs, with unprecedented consequences for ecosystem function. For instance, in tropical terrestrial ecosystems, hunters remove a large proportion of the standing mammalian biomass reducing population densities by 60-100%. Most of these vertebrates are large-bodied species in distinct trophic levels. Theoretical and empirical studies have found that apex consumers play a fundamental role in food web structure and stability in temperate biomes. Large-bodied forest dwelling vertebrates comprise important top predators, seed dispersers and herbivores, and their loss may lead to trophic cacades. Therefore, defaunation is likely to erode key ecosystem processes with far-reaching consequences. Current ecological knowledge indicates that apex consumers are fundamental in the maintenance of biodiversity and ecosystem functions. Human hunting in key elements of the food web may lead to trophic cascades, yet we lack information from non-fragmented tropical ecosystems. The Atlantic rainforest have more than 80% of the woody plant species dispersed by vertebrates and it is estimated that 88% of its area is under trophic cascade due to the extinction of apex consumers. Most of our understanding of trophic cascades is based on temperate biomes or fragmented landscapes, which cannot be easily extrapolated to larger scales. In this proposal, we seek to understand long-term effects of defaunation on trophic cascades, particularly in plant composition, and examine functional changes in forest dynamics and composition (diversity, functional organization and carbon stock) in continuous Atlantic Forest remnants. This proposal is part of a working group on Pantropical Mammalian Effects on Plant Communities organized by OTS (Organization of Tropical Studies) where several protocols will follow the ones used in Meso-america (México, BCI and La Selva), Africa and Asia. (AU)