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Species invasion progressively disrupts the trophic structure of native food webs

November 1, 2021

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.

Citation Information

Publication Year 2021
Title Species invasion progressively disrupts the trophic structure of native food webs
DOI 10.1073/pnas.2102179118
Authors Charles Wainright, Clint C. Muhlfeld, James J. Elser, Samuel Bourret, Shawn P. Devlin
Publication Type Article
Publication Subtype Journal Article
Series Title Proceedings of the National Academy of Sciences
Series Number
Index ID 70230780
Record Source USGS Publications Warehouse
USGS Organization Northern Rocky Mountain Science Center