Species invasion progressively disrupts the trophic structure of native food webs

Charles Wainright; Clint C. Muhlfeld; James J. Elser; Samuel Bourret; Shawn P. Devlin

doi:10.1073/pnas.2102179118

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Species invasion progressively disrupts the trophic structure of native food webs

Charles Wainright·Clint C. Muhlfeld·James J. Elser·Samuel Bourret·Shawn P. Devlin

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Abstract

Species invasions can have substantial impacts on native species and ecosystems, with important consequences for biodiversity. How these disturbances drive changes in the trophic structure of native food webs through time is poorly understood. Here, we quantify trophic disruption in freshwater food webs to invasion by an apex fish predator, lake trout, using an extensive stable isotope dataset across a natural gradient of uninvaded and invaded lakes in the northern Rocky Mountains, USA. Lake trout invasion increased fish diet variability (trophic dispersion), displaced native fishes from their reference diets (trophic displacement), and reorganized macroinvertebrate communities, indicating strong food web disruption. Trophic dispersion was greatest 25 to 50 y after colonization and dissipated as food webs stabilized in later stages of invasion (>50 y). For the native apex predator, bull trout, trophic dispersion preceded trophic displacement, leading to their functional loss in late-invasion food webs. Our results demonstrate how invasive species progressively disrupt native food webs via trophic dispersion and displacement, ultimately yielding biological communities strongly divergent from those in uninvaded ecosystems.

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Proceedings of the National Academy of Sciences Article

Source-reported bounding extent: 46.73986059969267° to 49.01625665778159° latitude; -116.05957031249999° to -113.367919921875° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

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Charles Wainright, Clint C. Muhlfeld, James J. Elser, Samuel Bourret, Shawn P. Devlin. 2021. Species invasion progressively disrupts the trophic structure of native food webs. https://doi.org/10.1073/pnas.2102179118

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