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Concordance of taxonomic composition patterns across multiple lake assemblages: effects of

Summary: Concordance of taxonomic composition patterns
across multiple lake assemblages: effects of
scale, body size, and land use
Andrew P. Allen, Thomas R. Whittier, David P. Larsen, Philip R. Kaufmann,
Raymond J. O'Connor, Robert M. Hughes, Richard S. Stemberger,
Sushil S. Dixit, Ralph O. Brinkhurst, Alan T. Herlihy, and Steven G. Paulsen
Abstract: We assessed environmental gradients and the extent to which they induced concordant patterns of taxonomic
composition among benthic macroinvertebrate, riparian bird, sedimentary diatom, fish, and pelagic zooplankton
assemblages in 186 northeastern U.S.A. lakes. Human population density showed a close correspondence to this
region's dominant environmental gradient. This reflected the constraints imposed by climate and geomorphology on
land use and, in turn, the effects of land use on the environment (e.g., increasing lake productivity). For the region as a
whole, concordance was highest among assemblages whose taxa were relatively similar in body size. The larger-bodied
assemblages (benthos, birds, fish) were correlated most strongly with factors of broader scale (climate, forest
composition) than the diatoms and zooplankton (pH, lake depth). Assemblage concordance showed little or no
relationship to body size when upland and lowland subregions were examined separately. This was presumably because
differences in the scales at which each assemblage integrated the environment were obscured more locally. The larger-
bodied assemblages showed stronger associations with land use than the diatoms and zooplankton. This occurred, in
part, because they responded more strongly to broad-scale, nonanthropogenic factors that also affected land use. We
argue, however, that the larger-bodied assemblages have also been more severely affected by human activities.
Résumé : Nous avons évalué les gradients environnementaux et la mesure dans laquelle ils induisaient des concordances


Source: Allen, Andrew P. - National Center for Ecological Analysis and Synthesis, University of California at Santa Barbara


Collections: Environmental Sciences and Ecology