Predicting the impacts of changing species distributions on fish species in Ontario lakes
In Ontario, several warm and coolwater predatory fishes have shifted their distributions northward over nearly 30 years of climate warming. Using contemporary and historical survey data from more than 1500 lakes across the province we examined which species were most vulnerable to introductions of centrarchid predators outside of their historical range. We use historical species associations (measured using the Phi coefficient) and body size to predict the impacts of these species introductions (measured using the Relative Risk Ratio).
We find that introductions of predators which are expanding their ranges appear to negatively impact both native top predators and their prey. Species which were historically negatively associated with centrarchid predators were more likely to be lost from lakes were the predators were introduced. With gape-limited predation, smaller resident species were also at greater risk. Our methods to identify those species most vulnerable to introductions facilitated by climate change and can easily be applied to a range of taxa undergoing range expansions.