The reassembly of faunal communities and species interactions in regenerating tropical forests and their potential applications to restoration initiatives

As deforestation and biodiversity loss continue to damage tropical forests around the globe, these ecosystems become less capable of maintaining organismal communities and ecological functions essential to their persistence. Ecosystem resilience, or the ability for forests to retain or reestablish their structure, functions, and interactions after a disturbance, depends on remnant biodiversity and species functional roles within the ecosystem. Therefore, restoring functional communities and strengthening ecological interactions is essential for promoting tropical forest regeneration and ensuring the long-term persistence of tropical ecosystems. In this dissertation, we explore the dynamics of assessing faunal community assembly and interaction recovery in regenerating tropical forests and their implications for forest restoration. First, we conducted a systematic review of studies utilizing seed dispersal networks in conservation and restoration, identifying major findings, methodological biases, and suggestions for future research directions. In this review, we highlight the importance of targeting species-rich, generalist interactions in early stages of forest regeneration while promoting stable and resilient interaction networks as forests mature. Second, we used functional diversity measures to test their applicability in assessing understory bird community responses to forest regeneration in the Chocó Rainforest of Northwest Ecuador. We found that not all functional diversity indices are indicative of community responses to forest regeneration, as only functional dispersion, functional divergence, and Rao’s quadratic entropy were associated with closed-canopy habitats and later stages of regeneration. Furthermore, we found that sampling for functional diversity requires less effort than traditional taxonomic surveys, which could be useful when utilizing these tools in restoration assessments. Lastly, we used ecological network analysis to investigate the reassembly of seed dispersal interactions across regenerating forests. Seed dispersal networks transitioned from loosely connected, generalist systems in early successional habitats to more specialized, modular, and nested networks in later stages of forest succession. Early stages of regeneration that promote a high number of diverse interactions may be pivotal in shaping successional trajectories for stable ecosystems. Together, our findings have implications for tropical forest restoration by emphasizing elucidating the importance of select functional measures and assessing species interaction recovery to achieve long-term ecological resilience for regenerating tropical forests.