The Dual Nature of CommunityVariability.
F. Micheli, K.L. Cottingham,J. Bascompte, O.N. Bjørnstad, G.L. Eckert, J.M. Fischer, T.H. Keitt,B.E. Kendall, J.L. Klug, and J.A. Rusak, 1999
Oikos, 85: 161-169.
ABSTRACT: Community variabilityhas a dual nature. On the one hand, there is compositional variability,changes in the relative abundance of component species. On the other hand,there is aggregate variability, changes in summary properties such as totalabundance, biomass, or production. Although these two aspects of variabilityhave received much individual attention, few studies have explicitly relatedthe compositional and aggregate variability of natural communities. Inthis paper, we show how simultaneous consideration of both aspects of communityvariability might advance our understanding of ecological communities.We use the distinction between compositional and aggregate variabilityto develop an organizational framework for describing patterns of variabilityin natural communities. At their extremes, compositional and aggregatevariability combine in four different ways: (1) stasis, low compositionaland low aggregate variability; (2) synchrony, low compositional and highaggregate variability; (3) asynchrony, high compositional and high aggregatevariability; and (4) compensation, high compositional and low aggregatevariability. Each of these patterns has been observed in natural communities,and can be linked to a suite of abiotic and biotic mechanisms. We giveexamples of the potential relevance of variability patterns to appliedecology, and describe the methodological development needed to make meaningfulcomparisons of aggregate and compositional variability across communities.Finally, we provide two numerical examples of how our approach can be appliedto natural communities.
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