Postdoctoral Fellowship: PRFB: From individuals to landscapes: scaling plant carbon tradeoffs in African savannas

This action funds an NSF Postdoctoral Research Fellowship in Biology for FY 2025. The fellowship supports research and training of the fellow that will contribute to biology in innovative ways. Savanna ecosystems, defined by the coexistence of trees and grasses, cover approximately 20% of the world’s land surface and provide substantial economic and environmental value.

Many savannas are undergoing dramatic changes in tree cover driven by human activity, which has already resulted in altered livestock forage, degraded wildlife habitat, and changes in landscape resource (e.g., carbon) storage. Predicting future changes in tree cover requires understanding how different tree species will respond to environmental change.

For example, changes in rainfall or consumption by herbivores may cause savanna trees to allocate resources differently between growth, defense (such as thorns), and storage. This project will quantify how tree resource allocation varies across species in an African savanna and determine how these strategies scale up to drive changes in tree cover and species composition across environmental gradients.

As part of the project, the fellow will also host workshops and training sessions for undergraduate and graduate students interested in ecology at several local institutions in Indiana.

Using a combination of experimental, modeling, and remote sensing approaches, the fellow will address 3 aims: (1) quantify how rainfall and herbivory interact to shape the carbon allocation strategies of dominant savanna tree species, (2) assess how variation in carbon allocation strategies scale up to shape tree population trajectories under various rainfall and herbivory regimes, and (3) use high-resolution light detection and ranging data to map temporal and spatial changes in aboveground carbon density as a function of rainfall, herbivore abundance, and topography. To address these aims, the fellow will use a common garden experiment and field surveys conducted within a long-term herbivore exclusion experiment in Kenya to characterize species-specific carbon allocation strategies across tree size classes.

The fellow will then integrate the physiological measurements with long-term demographic data to investigate how species-specific strategies influence community-level responses to variation in rainfall and herbivory. Finally, the fellow will use remote sensing data to map carbon density across a 20,000-ha savanna ecosystem. The fellow will receive training in process-based models and remote sensing techniques.

Further, the work will support research training and the development of international collaborations for undergraduate and graduate students.

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.