Trait-based recovery trajectories of prey communities following top predator removal

Non-native species have been introduced to ecosystems worldwide by accident and intentionally. For example, mountain lakes have been stocked with non-native fish that are ecologically disruptive predators. While much is known about the impacts of these fish on the sensitive alpine ecosystems, there is little known about the recovery trajectories once fish are removed.

After fish removal, a succession of different prey species may reestablish in the lakes, resulting in some lakes that look like natural fishless ecosystems, while other lake communities may not recover to a pre-invasion condition. This project examines the return of the former prey species and delves into the functional traits of those prey species and ecosystem functions crucial for ecosystem resilience.

The research will provide new insights into the connections between taxonomic and functional recovery. The project’s focus on functional redundancy as a vulnerability indicator will contribute to the broader understanding of ecosystem resilience. Using a combination of large-scale lake surveys and experiments, this project will elucidate fundamental principles of community recovery and establish a robust foundation for trait-based conservation in the face of unprecedented and pressing environmental challenges.

Additional impacts include educating local communities about natural history and ecological research and creating an educational resource to train the next generation of ecologists in multivariate data analysis.

Community assembly frameworks, centered on taxonomic units, inadequately predict ecosystem function due to context-dependent species traits, leaving a gap in our understanding of ecosystem dynamics. This project bridges the gap between taxonomic and functional perspectives in ecology, recognizing the importance of traits in driving ecosystem function.

The mountain lakes of the Sierra Nevada in California will be used as a natural laboratory for studying community reassembly following non-native fish removal. Plankton and trait data from 421 lakes will allow a robust comparison of the recovery trajectories of zooplankton community taxonomic and functional structures following fish eradication. To complement the survey data, a replicated whole-lake fish removal will examine the short-term dynamics of zooplankton recovery.

Finally, a large-scale mesocosm experiment will determine how communities with varying levels of functional redundancy respond to disturbance, testing the utility of functional redundancy as a community vulnerability indicator.

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.