NEUTRAL THEORY AND THE EVOLUTION OF ECOLOGICAL EQUIVALENCE

EcologyVolume 87, Issue 6 p. 1387-1398 Special Feature—Neutral Community Ecology NEUTRAL THEORY AND THE EVOLUTION OF ECOLOGICAL EQUIVALENCE Stephen P. Hubbell, Stephen P. Hubbell Department of Plant Biology, University of Georgia, Athens, Georgia 30605 USA, and Smithsonian Tropical Research Institute, Box 2072, Balboa, PanamaSearch for more papers by this author Stephen P. Hubbell, Stephen P. Hubbell Department of Plant Biology, University of Georgia, Athens, Georgia 30605 USA, and Smithsonian Tropical Research Institute, Box 2072, Balboa, PanamaSearch for more papers by this author First published: 01 June 2006 https://doi.org/10.1890/0012-9658(2006)87[1387:NTATEO]2.0.CO;2Citations: 354 Corresponding Editor: M. Holyoak. For reprints of this Special Feature, see footnote 1, p. 1368. Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Abstract Since the publication of the unified neutral theory in 2001, there has been much discussion of the theory, pro and con. The hypothesis of ecological equivalence is the fundamental yet controversial idea behind neutral theory. Assuming trophically similar species are demographically alike (symmetric) on a per capita basis is only an approximation, but it is equivalent to asking: How many of the patterns of ecological communities are the result of species similarities, rather than of species differences? The strategy behind neutral theory is to see how far one can get with the simplification of assuming ecological equivalence before introducing more complexity. In another paper, I review the empirical evidence that led me to hypothesize ecological equivalence among many of the tree species in the species-rich tropical forest on Barro Colorado Island (BCI). In this paper, I develop a simple model for the evolution of ecological equivalence or niche convergence, using as an example evolution of the suite of life history traits characteristic of shade tolerant tropical tree species. Although the model is simple, the conclusions from it seem likely to be robust. I conclude that ecological equivalence for resource use are likely to evolve easily and often, especially in species-rich communities that are dispersal and recruitment limited. In the case of the BCI forest, tree species are strongly dispersal- and recruitment-limited, not only because of restricted seed dispersal, but also because of low recruitment success due to heavy losses of the seedling stages to predators and pathogens and other abiotic stresses such as drought. These factors and the high species richness of the community strongly reduce the potential for competitive exclusion of functionally equivalent or nearly equivalent species. Citing Literature Volume87, Issue6June 2006Pages 1387-1398 RelatedInformation