Stochastic Community Assembly Causes Higher Biodiversity in More Productive Environments

Biodiversity and Productivity When data are analyzed at relatively large spatial scales, biodiversity generally increases with productivity, but the pattern at smaller scales is more variable. Chase (p. 1388 , published online 27 May) presents results from a 7-year experiment in artificial ponds. β-diversity (the variation in species composition from site to site) in animal species was persistently higher at higher productivity among otherwise homogeneous environments in this controlled experimental venue. This pattern appeared to result from shifts in the relative importance of deterministic versus stochastic community assembly mechanisms along the productivity gradient. Thus, variation in the mechanism of community assembly might be an important process determining the relationship between biodiversity and productivity.