Print PageClimate change is predicted to alter the range limits of many fish species, including smallmouth bass (Micropterus dolomieu). Shifting species distributions will produce novel species assemblages and may significantly alter species interactions and lake community composition. Additionally, theory suggests that a species may be more likely to invade when it occupies a niche which is unused by the resident community and consequently that more diverse communities should be more resistant to invasions. Using historical and contemporary data on species occurrences in Ontario lakes, we examined whether particular types of fish communities are more vulnerable to species introductions. While controlling for environmental variation (including lake morphometry and location), we test whether pre-existing community composition differs between paired lakes where introduced species are present and absent.
Results/Conclusions
The range of smallmouth bass in Ontario is expanding at its northern limit. Our results indicate introduced smallmouth bass are more likely to establish in communities with lower cyprinid species richness. Also, smallmouth bass are more likely to establish in lakes with lake whitefish (Coregonus clupeaformis) and walleye (Sander vitreus), but less likely to establish in those with brook trout (Salvelinus fontinalis). Understanding the relationship between fish community composition and the likelihood of species establishment should help resource managers to evaluate the relative risks of introductions facilitated by climate change.
