spatial structure alters the shape of the unimodal species richness-biomass relationship in a neutral model空间结构改变的形状单峰物种richness-biomass中性模型的关系.pdf

Diversity 2010, 2, 550-560; doi:10.3390/d2040550 OPEN ACCESS diversity ISSN 1424-2818 /journal/diversity Article Spatial Structure Alters the Shape of the Unimodal Species Richness-Biomass Relationship in a Neutral Model Daniel J. McGlinn 1,* and Michael W. Palmer 2 1 Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA 2 Department of Botany, Oklahoma State University, Stillwater, OK 74078, USA; E-Mail: mike.palmer@ * Author to whom correspondence should be addressed; E-Mail: danmcglinn@; Tel.: +1-919-962-8795. Received: 5 January 2010; in revised form: 30 March 2010 / Accepted: 1 April 2010 / Published: 6 April 2010 Abstract: Variation in individual density may explain the unimodal richness-biomass relationship in which species richness peaks at an intermediate level of total biomass . However, it is unclear how individual density is regulated by community thinning (i.e., mortality due to competition with neighbors) as total above-ground biomass increases. We developed a simulation model which demonstrates that the spatial structure of a population can influence the initiation and rate of community thinning and thus the shape of the richness-biomass relationship. Specifically, we found that more clustered populations resulted in a more abrupt initiation and rapid rate of thinning and thus a sharper unimodal richness-biomass relationship. Our simulation also demonstrated that a wide