Dimensions US-São Paulo: animal biases in fruit selection and seed dispersal as drivers of biotic filters in the assembly of successional forests and their carbon capture potential

Abstract

Tropical forests play a major role in regulating the earth's climate through their effects on water cycles and their immense capacity to sequester and store atmospheric carbon. Because of their global preeminence and the threats they face, understanding the mechanisms governing community assembly, biodiversity, resilience, and emergent ecosystem functions of tropical forests is urgent. Frugivory and Seed Dispersal (FSD) are overlooked mutualistic processes involving communities of fruit-eating vertebrates (frugivores) and fleshy-fruited plants that dominate tropical forests. In fact, the vast majority of Neotropical trees depend on frugivores, most commonly birds, to disperse their seeds. This places FSD interactions as a central process directly affecting the assembly and resilience of tropical forests in the face of widespread forest disturbance and destruction. But large gaps persist in our understanding of tropical forests since FSD processes have not been seriously considered by core ecological theories. Gaps are also due to the absence of large manipulative field experiments that explore community assembly and functionality in the tropics. This project will provide a novel and rigorous experimental test to integrate multiple theories and mechanisms to advance understanding of tropical forest assembly, biodiversity patterns, and ecosystem functions. This project builds around three Aims that link phylogenetic, genetic, and functional aspects of biodiversity in the context of the role of FSD interactions on community assembly patterns of early-successional tropical forests. With an experimental design that strategically incorporates functional plant traits and phylogenetic relationships as fixed-effects, the project test functional relationships between FSD processes and phylogeny in affecting community assembly (aim 1). The project then examines how the interaction of FSD processes with the functional-phylogenetic traits of pioneer plant species affect the genetic diversity of the plant colonizer species that follow, and in turn, how patterns of genetic diversity lead to differences in plant survival, growth, and community assembly (aim 2). The project ultimately explores how the biotic filtering interactions of FSD processes and the functional and phylogenetic trait diversity of successional communities influence, or are influenced by, soil microbiomes and the nutrient pools and carbon transformation processes they control (aim 3). This project will advance fundamental knowledge by exploring ecological mechanisms and outcomes across disparate scales of biological organization rarely brought together in a single experimental framework. From trophic and seed-dispersal processes linking vertebrates and plants, to soil microbial communities and their role in mediating biogeochemical cycling of essential elements in ecosystems. (AU)