Abstract
The introduction of exotic species is considered a major threat to global biodiversity and the ongoing climate change could alter species distributions. This project aims to assess feeding characteristics of invasive species and to find out if species with wide feeding niches (generalists) have greater impact on their new environment than species with narrow feeding niches (specialists) has. During my post-doc stay I will apply a new method for studying variability in feeding niche width using stable isotopes, where the area enclosed by nitrogen and carbon signals estimates niche width. I will also learn a new statistical tool to examine directional changes, over e.g. time, in food web structure. Model invaders in Wisconsin, USA are the rusty crayfish (wide feeding niche) and the round goby (narrower feeding niche) in lake and stream food webs, respectively. I will collect stable isotope data from food webs in lakes with high and low impact of invaders and in streams where there is an ongoing invasion. This enables me to evaluate a) if niche width determines invasive impact, b) if niche width changes along an invasion gradient, and c) how the invader affects food web structure. This project will assess how feeding niche width affects impact of invaders, which aids in predicting what species are potential invaders and their effects on the new food web. The new methods I will apply for analysing stable isotope data put the project at the frontier in food web ecology.
Sweden