Spatio-temporal niche plasticity of a freshwater invader as a harbinger of impact variability

Invasive alien fishes have detrimental ecological effects on aquatic ecosystems and the services they provide. Impacts from an invasion in a single ecosystem may differ across space time due to variability prey availability environmental conditions. We hypothesize that such can be profound, even within ecosystem. Stable isotopes analysis (SIA) is commonly used quantitatively describe trophic niche of species. However, spatial temporal occupied niches are often not incorporated into management strategies policy options. Here, we long-term monitoring data investigate stage as well SIA analyse invasive channel catfish Ictalurus punctatus Lake Kasumigaura (Japan), research site (LTER), distant sampling sites years. found significant spatio-temporal relative growth isotopic occupation. Moreover, defined new index, Isotopic Plasticity Index (IPI), which ratio between core total home range niche, proxy for stretch or density. this IPI varied considerably, confirming niches, suggesting adequate metric. Our results further provide evidence existence variation invaded landscapes, implying heterogeneous impacts recipient native communities. Therefore, our work emphasizes importance exploring plasticity feeding ecology information enables better understanding inform design implementation effective responses.