SYMP 22-2 - Biodiversity and ecosystem multifunction in metacommunities

Friday, August 11, 2017: 8:30 AM
Portland Blrm 257, Oregon Convention Center
Andrew Gonzalez, Department of Biology, McGill University, Montreal, QC, Canada and Patrick L. Thompson, Department of Zoology, University of British Columbia, Vancouver, BC, Canada

Human well-being depends upon the supply of ecosystem services that are sustained by multiple ecosystem functions, such as biomass production, nutrient cycling, and pollination. Ecosystem multifunctionality, the simultaneous production of multiple ecosystem functions, depends on community diversity, composition, productivity, and spatial scale. In metacommunities, each of these community properties is affected by how species disperse between local patches to track environmental change. After summarizing current knowledge linking biodiversity to ecosystem functioning in metacommunities we will use a metacommunity model of resource competition to show how connectivity affects the link between diversity, stability and ecosystem multifunctionality. We assume that species are capable of contributing to multiple ecosystem functions and we show how their contribution to them varies in space and time. Our model focuses on the multifunctionality of producer communities, which have been the focus of most empirical studies to date.


When species differ in their functional traits and environmental niche, metacommunity multifunctionality becomes highly dependent upon dispersal, which allows community diversity to be maintained when environmental conditions change. Dispersal promotes multifunctionality in two ways: (1) species sorting, whereby species track local environmental changes by shifting in space, thus preserving diversity and ensuring high biomass productivity, and (2) mass effects, whereby source–sink dynamics allow species to persist in suboptimal environments, thus increasing local diversity. Changing the rate at which species disperse affects the balance of the two processes. We find that metacommunity multifunctionality exhibits a nonlinear relationship with dispersal rate. Species-sorting dynamics also provide spatial insurance whereby compensatory dynamics stabilize the fluctuations of each function through time at the regional scale. However, this does not extend to the local scale, where species sorting results in high temporal variability of each function, even though the overall rates of multifunctionality are high. Our results suggest that metacommunity processes are important determinants of ecosystem multifunctionality, and thus effective landscape management for multiple ecosystem functions and services requires explicit consideration of landscape connectivity.