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The Dynamics of Metacommunities

 In nature, many habitats are distributed patchily over landscapes. This patchiness can either be natural or caused by fragmentation due to anthropogenic activities. A network of habitat patches connected by dispersal of multiple interacting species is defined as a metacommunity. The emerging properties of a metacommunity result from the interplay of local and regional processes. Here we study the effects of different types of disturbances on metacommunities.

Project 1: Paradox of Enrichment in Metacommunities

Nutrient enrichment of ecosystems caused by anthropogenic activities can modify structure of communities and their stability. Theory predicts that the stability of predator-prey communities decreases when prey resources increase. This "paradox of enrichment" has been observed in controlled experiments but not in natural systems suggesting that other mechanisms act in nature. We investigate the paradox of enrichment in a spatial context. Using a theoretical model, we explore the roles of dispersal and body sizes in the response of predator-prey metacommunities to enrichment. This work is realized in collaboration with Nicolas Mouquet, Elsa Canard and Grégoire Nadin.

Céline Hauzy & Bo Ebenman

Project 2: Effects of Environmental Variability on Local and Global Extinction in Metacommunities

Increased environmental variability may lead to increased species extinction risks and hence have important consequences for the structure and functioning of ecosystems. In this project we will use a stochastic metacommunity model to explore the effects of environmental variability on local and global extinction in metacommunities. More specifically we are interested in examining the effects of the degree correlation in species responses to the environmental variation both within and between patches. We will also explore the role of local food web structure and dispersal abilities of species on the overall persistence of metacommunities exposed to environmental variation.

Linda Kaneryd, Peter Münger & Bo Ebenman

Project 3: Effects of Habitat Loss on the Persistence of Metacommunities

Human activities cause destruction and fragmentation to the natural habitats; this can lead to great losses of biodiversity in the near future. In order to take efficient conservation measures there is a need to investigate how ecological communities in a fragmented environment respond to perturbations like loss of habitat fragments. The structural position that individual patches occupy can be used to understand their possible effects on the landscape’s connectivity. In order to preserve functional landscape’s it is important to be able to asses the vulnerability of a landscape’s connectivity to the loss of a single patch. Network measures can be used to identify structures and patches that are important for keeping the metacommunity network from disconnecting and hence reduce its robustness to perturbations. In order to asses the effects of a patch’s position in the landscape on the overall connectivity of network, each patch will be removed from the network one at a time. With this approach we will be able to identify keystone patches that are responsible for preserving the overall connectivity in the network.

Linda Kaneryd, Peter Münger & Bo Ebenman


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Last updated: 02/18/11