Of terns and change: eco-evolutionary dynamics in a rapidly changing environment

• Applicant: Dr. Maria Moiron Cacharron
• Subject Area: Evolution, Anthropology
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 540199894

The recent realization that evolutionary change can affect ecological and demographic processes relatively fast and thus determine populations’ ability to cope with rapid changes in the environment has led to a swift increase in studies focusing on the feedbacks between ecology and evolution (“eco-evolutionary dynamics”). While there is accumulating empirical evidence showing the existence of eco-evolutionary dynamics in wild and laboratory work, hypothesis-driven case studies that make explicit predictions on the existence and magnitude of dynamic feedbacks between ecology and evolution are now required to fully unravel the power to predict populations’ dynamics. This project offers a framework of eco-evolutionary dynamics based on powerful hypothesis-driven experimental tests rooted in a solid theoretical background. It is novel by explicitly testing for different scenarios where we expect or not evolution to lead to changes in population dynamics in light of theoretical predictions concerning density- and/or frequency-dependent selection and environmental variation. We will address these questions by means of empirical tests using a unique long-term individual-based dataset of a free-living population of common terns (Sterna hirundo), which is readily available. First, we will identify the most biologically-relevant density metric (i.e., population vs individual breeding density) as a source of variation in the social environment, and use that metric to study how variation in density influences eco-evolutionary dynamics. By testing for density-dependent selection we will directly quantify the link between natural selection and population dynamics. Second, we will combine in a single analysis density- and frequency-dependent selection patterns for a more complex, realistic scenario of eco-evolutionary dynamism in the wild, which will ultimately help to elucidate the intricated roles of each of the selection processes and their interaction on the dynamics between evolution rate and population size. Third, we will test for the impact of multiple abiotic factors on the population’s ability to adapt to rapid environmental change and the demographic costs of those adaptations, with a special emphasis on the nature of the selective processes underlying changes in evolutionary responses (i.e., a sustained decrease in food availability vs. a sudden pandemic outbreak). In summary, the results of this project will provide unprecedented insights on how eco-evolutionary feedbacks respond to rapidly changing environmental conditions, like the ones posed by current global and climate changes, and will ultimately help refine predictions on the future of biodiversity.

• DFG Programme: Research Grants