View article

Concern that the rapid anthropogenic erosion of biodiversity (Wilson 1992) may undermine the delivery of ecosystem services (Daily 1997) has prompted a synthesis of community and ecosystem ecology over the last decade. Biodiversity-ecosystem functioning (BEF) research is central to this emerging synthesis, asking how biodiversity is related to the magnitude and stability of ecosystem processes. Isolating species richness (and diversity) effects from species composition has been a chief goal of BEF research. That species richness generally enhances the mean magnitude of a variety of ecosystem properties is now well established (Hooper et al. 2005; Balvanera et al. 2006; Cardinale et al. 2006a), but the effect of species richness on the stability of ecosystem properties remains equivocal (Hooper et al. 2005). Early consensus (Odum 1953, MacArthur 1955, Elton 1958, Pimentel 1961) that diversity enhances various aspects of community and ecosystem stability was largely founded on qualitative observations and intuitive reasoning. This view was apparently contradicted by the results from rigorous mathematical treatments (eg May 1972) which showed that in a food web context stability was related to system properties, ie connectance, species richness, and interaction strength, and importantly, could be reduced by species richness. Recognition that stability has multiple definitions that can apply to all levels of ecological organization (Pimm 1984; see also Loreau et al. 2002) helped pave the way for a new, synthetic perspective that developed during the 1990s as attention to extinction’s consequences for the stability of ecosystem …