stochastic species turnover and stable coexistence in a species-rich, fire-prone plant community随机物种周转率稳定共存物种丰富,易燃植物群落.pdfVIP

Stochastic Species Turnover and Stable Coexistence in a Species-Rich, Fire-Prone Plant Community 1 2 2 3 Wilfried Thuiller *, Jasper A. Slingsby , Sean D. J. Privett , Richard M. Cowling ´ 1 Laboratoire d’Ecologie Alpine, CNRS-UMR 5553, Universite Joseph Fourier, Grenoble, France, 2 Department of Botany, University of Cape Town, Rondebosch, South Africa, 3 Department of Botany, Nelson Mandela Metropolitan University, Port Elizabeth, South Africa Understanding the mechanisms that maintain diversity is important for managing ecosystems for species persistence. Here we used a long-term data set to understand mechanisms of coexistence at the local and regional scales in the Cape Floristic Region, a global hotspot of plant diversity. We used a dataset comprising 81 monitoring sites, sampled in 1966 and again in 1996, and containing 422 species for which growth form, regeneration mode, dispersal distance and abundances at both the local (site) and meta-community scales are known. We found that species presence and abundance were stable at the meta- community scale over the 30 year period but highly unstable at the local scale, and were not influenced by species’ biological attributes. Moreover, rare species were no more likely to go extinct at the local scale than common species, and that alpha diversity in local communities was strongly influenced by habitat. We conclude that stochastic environmental fluctuations associated with recurrent fire buffer populations from extinction, thereby ensuring stable coexistence at the meta-community scale by creating a ‘‘neutral-like’’ pattern maintained by niche-differentiation. Citation: Thuiller W, Slingsby JA, Privett SDJ, Cowling RM (2007) Stochastic Species Turnover and Stable Coexistence in a Species-Rich, Fire-Prone