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Quantifying the potential effects of climate change and the invasion of smallmouth bass on native lake trout populations across Canadian lakes

Sharma, Sapna, Jackson, Donald A., Minns, Charles K.
Ecography 2009 v.32 no.3 pp. 517-525
Micropterus dolomieu, Salvelinus namaycush, animal communities, data collection, ecosystems, forage, geography, global warming, indigenous species, invasive species, lakes, population growth, risk, Canada, Lake Ontario
Climate change and invasive species are two stressors that should have large impacts on native species in aquatic and terrestrial ecosystems. We quantify and integrate the effects of climate change and the establishment of an invasive species (smallmouth bass Micropterusdolomieu) on native lake trout Salvelinus namaycush populations. We assembled a dataset of almost 22 000 Canadian lakes that contained information on fish communities, lake morphologies, and geography. We examined the pelagic-benthic and littoral forage fish community available to lake trout populations across three lake size classes in these aquatic ecosystems. Due to the decreased presence of alternate prey resources, lake trout populations residing in smaller lakes are more vulnerable to the effects of smallmouth bass establishment. A detailed spatially and temporally explicit approach to assess smallmouth bass invasion risk in Ontario lakes suggests that the number of Ontario lakes with vulnerable lake trout populations could increase from 118 (~1%) to 1612 (~20%) by 2050 following projected climate warming. In addition, we identified nearly 9700 lake trout populations in Canada threatened by 2100, by the potential range expansion of smallmouth bass. Our study provides an integration of two major stressors of ecosystems, namely climate change and invasive species, by considering climate-change scenarios, dispersal rates of invasive species, and inter-specific biotic interactions.