BoCP-Implementation:US-Sao Paulo: Living on the edge: plant-animal interactions and the cascading impacts of Amazon forest fragmentation

Yale University, New Haven CT

Investigators

Abstract

The fate of the world's most extensive tropical forest located the Amazon basin, is fundamentally linked to the complex relationships between tree species diversity, natural disturbances, human modifications of the landscape. Depending on how these processes interact with unprecedented heat, drought, and forest clearing, some Amazonian forest regions could lose their resilience and experience a large-scale collapse by mid-century. Because of the importance of tropical forests in regulating climate and acting as a massive carbon sink, such a collapse would have negative consequences at local, regional, and global scales. This project addresses how fragmentation at forest-agricultural boundaries fundamentally alters not only the local climate, thereby driving the morality of key tree species, but also disrupts and displaces the animals that play a crucial role in seed dispersal, nutrient distribution, and maintaining complex food webs. The breakdown of these ecosystems through direct and indirect human influence may permanently alter the Amazonian landscape, but our understanding of how these complex systems respond to disturbance at the present scale is limited. This research project aims to quantify how the changes in the relationships between tree traits and ecological processes controlled in part by animals may determine the forest's ability to withstand and recover from the increasing diversity of disturbances. The study focuses on Amazonian forests growing near hot and dry agricultural fields across the southeast portion of the basin. The project is a collaborative effort, uniting a diverse and interdisciplinary team of U.S. and Brazilian scientists and mentoring graduate students and postdoctoral researchers from both nations. The research will provide valuable information for understanding how, when, and why forest fragmentation leads to large-scale forest dieback. This project integrates field-based measurements of forest dynamics and animal exclusion experiments, remote sensing mapping of forest fragmentation, and statistical modeling of species distribution to examine how alterations in functional diversity due to mortality events and animal activities shape the resilience of Amazon forest edges. These alterations manifest as dry-warm forest edges, habitat loss, and shifts in the dietary habits of large mammals, driven by cultivated crops. At the local scale, the project will quantify how forest edge effects influence tree mortality and regeneration patterns following droughts and wildfires based on forest inventories. Expanding the scope to a regional scale, the project will gather ecophysiological traits of trees, forest dynamics from repeated inventories, and data on animal activity in three regions of the Amazon. These complementary datasets serve to broaden our understanding of the interconnectedness of global changes, tree traits, and vulnerability within the broader ecological context across a gradient in climate. Zooming out to the Amazon Basin scale, the project leverages advanced remote sensing techniques and species distribution modeling to quantify forest vulnerability to climate change and fragmentation. Examining how these ecosystems respond to disturbances across multiple spatial scales, from the local to the basin-wide, the project aspires to provide insights that are not only scientifically illuminating but also fundamentally essential for the preservation and restoration of one of the world's most remarkable and vital ecosystems. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.