Spatial ecosystems in varying environments: distribution, stucture and functioning

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Global changes modify the structure of ecosystems with species addition and removal and it alters their functioning. Global changes affect first the organisms on an individual basis, and then propagate up to the population, species and ecosystem levels. Global changes also affect species indirectly because of an entangle web of ecological interactions. My research program aims at understanding how the structure of these complex ecosystems is affected by environmental changes, and how in return this alteration of their organization affects their functioning. I use in combination mathematical, computer and biological models to answer this question. Scientists currently use species distribution models to undertand the effect of global changes on biodiversity that neglect the interactions between species. Organisms in an ecosystem are however organized in diverse networks of ecological interactions and consequently predictions at the species level might lead to erroneous conclusions. The specific objectives of this project are: i) understand how the structure of complex ecological networks is affected by the movement of organisms in a changing environment; ii) develop novel methodologies based on the study of ecological networks to predict the ecosystem-level consequences of global changes; iii) understand how the alteration of this structure affects the functioning of complex ecosystems and iv) test experimentally this theory with the food web contained in the carnivorous plant Sarracia purpurea. The Sarracenia purpurea provides an interesting biological model because it is a complete ecosystem with well defined boundaries, that includes nutrient recycling and that could be easily manipulated experimentally. This project will allow the identification of species characteristics making them vulnerable to global changes and the characteristics associated with the most pronounced effects on ecosystem functioning. Identification of these characteristics is an essential step toward a predictive and general science of ecosystem's response to global changes.