Measuring and explaining the global debt of biotic homogenization in a changing world.

ended

The process The process of biotic homogenization corresponds to the increase in similarity between ecological communities through time. It is one of the most significant aspects of the current biodiversity crisis, and limiting its detrimental effects is gaining momentum in conservation biology. Lagged biodiversity responses to past environmental changes might result in disequilibrium states between community composition and present-day environmental conditions in many biomes and taxa across the planet. My hypothesis is that if delayed biodiversity responses affect the community compositions, they should also affect the similarity between communities. If so, lagged biodiversity responses to global changes might build a homogenization debt, here defined as a future increase of similarity between communities resulting from past environmental perturbation. This project will test the existence, quantify, and map the prevalence of the homogenization debt at a global scale, across biomes and taxa (terrestrial plants, birds, fish, and marine invertebrates). Using graphical, analytical and statistical methods, I will quantify disequilibrium states and dynamics of species turnover between communities, and formally test their link with a set of anthropogenic threats to biodiversity. The project will provide a novel assessment of the biotic homogenization at global scale, and a comprehensive assessment of its drivers. The first quantitative estimation and map of the homogenization debt will reveal areas where biodiversity is doomed to homogenize in the near future if no actions are undertaken. Thus, the project outcome will help to prioritize context-dependent conservation actions to mitigate future homogenization. Through this MSCA fellowship, I will acquire a new set of scientific (statistical development, big-data, new concept in ecology) and transversal (project and financial management) skills that will foster my capacity to reach a academic researcher position in France.