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Human development modifies the functional composition of lake littoral invertebrate communities

Twardochleb, Laura A., Olden, Julian D.
Hydrobiologia 2016 v.775 no.1 pp. 167-184
anthropogenic activities, community structure, ecosystems, energy flow, environmental indicators, environmental quality, food webs, functional diversity, habitats, herbivores, human development, humans, invertebrates, lakes, littoral zone, macrophytes, multivoltine habit, ordination techniques, phosphorus, shorelines, watersheds, Northwestern United States
Residential shoreline and watershed development by humans are leading agents of environmental change in lake ecosystems that reduce abundances and diversity of littoral invertebrates. Invertebrate functional and life history traits are robust indicators of environmental quality and ecosystem functioning, yet surprisingly few studies have utilized trait-based approaches to assess impacts of human development to lake littoral communities. We assessed environmental characteristics of human development that impact functional diversity and structure the trait composition of invertebrate communities in lakes of northwestern United States. Multiple linear regressions revealed that functional diversity declined with increasing watershed development, lake total phosphorus, and littoral macrophyte cover. Results from multivariate constrained ordination and fourth corner analysis indicated that high phosphorus concentrations and abundant macrophyte cover removed taxa with semivoltine life histories and filter feeders from lake communities, and that both regional ecosystem and local habitat characteristics of human development were important determinants of invertebrate community structure. Human development had particularly pronounced effects on invertebrate communities in the sublittoral zone, for which overall community abundances declined. Our study indicates that human development favors lake communities dominated by multivoltine taxa and herbivores, which may have important implications for energy flow among terrestrial, littoral, and pelagic food webs.