Data from: Global test of Eltonian niche conservatism of nonnative freshwater fish species between their native and introduced ranges

• Main Authors: Comte, Lise, Cucherousset, Julien, Olden, Julian D.
• Format: Dataset
• Language: unknown
• Published: 2016
• Subjects: Scardinius erythrophthalmus; Gymnocephalus cernua; Coregonus clupeaformis; Ameiurus nebulosus; Micropterus salmoides; Cyprinella lutrensis; Lepomis macrochirus; Pylodictis olivaris; Osmerus mordax; Salvelinus alpinus alpinus; Salvelinus fontinalis; Sander vitreus; Pseudorasbora parva; Cyprinus carpio; Pimephales promelas; Perca flavescens; Oncorhynchus nerka; Tilapia zillii; Sander lucioperca; Gambusia holbrooki; Lepomis gibbosus; Oncorhynchus mykiss; Morone chrysops; Ictalurus punctatus; Notemigonus crysoleucas; Oreochromis niloticus; Carassius auratus; Coregonus lavaretus; Rutilus rutilus; Micropterus dolomieu; Holocene; Salvelinus alpinus
• Online Access: https://zenodo.org/record/4979873; https://doi.org/10.5061/dryad.6q036

Despite growing evidence that biotic interactions limit the distribution of species and their potential redistribution under climate change, the recent surge of interest in niche conservatism has predominantly focused on the Grinellian (abiotic) niche, whereas few studies have attempted to quantify potential lability in the Eltonian (biotic or trophic) niche. Here, we test for conservatism in the Eltonian niche of 32 freshwater fish species between their introduced and native ranges from 435 populations across the globe. We used stable isotope data to quantify niche shifts along the horizontal (δ13C: indicating the origin of the resources consumed) and vertical (δ15N: describing the trophic position) dimensions of the isotopic niche, as well as shifts in overall isotopic niche breadth. Using an assemblage centroid standardized isotope vector analysis and controlling for phylogenetic relatedness among species, we demonstrated that introduced freshwater fishes exhibited flexibility in both resource use and trophic position that was beyond levels of natural variability observed in their native ranges. By contrast, niche breadth showed variability only within the limits recorded in native populations and varied independently from shifts in mean isotopic niche positions. Across all species and introduction histories, we found a consistent shift towards more balanced acquisition of resources with mixed origins and at intermediate trophic positions, suggesting a general mechanism by which fish species successfully establish into recipient communities. The mechanisms that promote or inhibit species from shifting their Eltonian niche remains unknown, but trophic flexibility is likely to contribute to both the success and the ecological impacts of invasive species and range shifts of native species under future global change. Stable isotopes characteristics of the fish species within their native and introduced rangestab_dryad.txt