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Resource quantity, not resource heterogeneity, maintains plant diversity
Author(s) -
Stevens M. Henry H.,
Carson Walter P.
Publication year - 2002
Publication title -
ecology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.852
H-Index - 265
eISSN - 1461-0248
pISSN - 1461-023X
DOI - 10.1046/j.1461-0248.2002.00333.x
Subject(s) - biodiversity , resource (disambiguation) , ecology , competitor analysis , spatial heterogeneity , productivity , biology , diversity (politics) , competitive exclusion , competition (biology) , species diversity , economics , macroeconomics , computer network , management , sociology , computer science , anthropology
Resource heterogeneity has often been proposed to explain the maintenance of plant species diversity and patterns of species diversity along productivity gradients. Resource heterogeneity should maintain biodiversity by preventing competitive exclusion because different species are superior competitors in different parts of a heterogeneous environment. In natural systems, however, resource heterogeneity covaries with average resource supply rate, making the effect of heterogeneity difficult to isolate. Using a novel experimental approach, we tested the independent effects of resource heterogeneity and average supply rate on plant species diversity. We show that the average supply rate of the most limiting resource controlled species diversity, whereas heterogeneity of this resource had virtually no effect. These findings also suggest that biodiversity declines with increasing productivity because at high enough levels of productivity one resource may always be driven to sufficiently short supply to exclude many species.