Monday, August 6, 2007: 2:30 PM
N, San Jose McEnery Convention Center
Claire F. Jouseau, UMR 7204 Conservation des Espèces, Restauration et Suivi des Populations, Muséum National d'Histoire Naturelle, Paris, France and Shahid Naeem, Ecology, Evolution and Environmental Biology, Columbia University, New York, NY
In a world of rapidly changing biodiversity, the ability to understand how changes in local communities will affect the stability of ecosystem processes has emerged as a pressing challenge for ecologists. Considerable debate continues around the relative contribution of species richness, composition, and environmental factors as drivers of community-level patterns. Here we present results from a field study in Minnesota old-fields examining the effect of plant diversity on community stability and whether the diversity-stability effect changes when soil fertility, land-use history, and gopher-mediated soil disturbance regimes are considered. Multiple measures of community stability were selected for evaluation including: variability in plant species richness and total foliar area, persistence in species composition and relative abundance, resistance to species turnover, and resilience or the recovery time from a soil disturbance event. Plant diversity was quantified using species richness and foliar area assessed annually in each of 880 neighborhood plots scattered across 11 fields and over 4 years. Multivariate analyses of stability suggest that variability, persistence, and resistance are dependent not only on overall plot diversity but also on species identity as native or exotic plants. Resilience is determined by both biotic and abiotic factors; after controlling for soil influences, higher resilience was found in the more diverse plots. These results suggest that under a natural soil disturbance regime, greater local diversity of native plants results in a more stable plant community.
