Ecosystem vulnerability to species loss
Species losses have always occurred as a natural phenomenon, but the pace at which species are going extinct has recently accelerated dramatically as a result of human activities. The disappearance of a species can have far-reaching and often unexpected consequences for other species, since changes can propagate throughout ecosystems. The principal aim of this project is to investigate the consequences of species losses in ecosystems. In this project, we develop and analyze a dynamic ecosystem network model, calibrated to a set of real ecosystems, to predict the cascading changes that can follow the extinction of a species. The impacts of such primary species losses are measured in terms of secondary species losses and biomass changes. Fundamental descriptors of ecosystem structure (such as the number of coexisting species, their connectivity, the ecosystem’s maximum tropic level) are assessed for their capacity to predict indicators of ecosystem vulnerability to species loss (such as the average number of species losses, the average biomass loss or gain, the average time to extinction). Particular emphasis is given to the relationship between an ecosystem’s structural complexity and vulnerability. It is anticipated that the results will be useful for ecosystem management and will contribute to community ecology’s long-standing complexity-stability debate.