Comparing Climate Change and Species Invasions as Drivers of Coldwater Fish Population Extirpations

Sapna Sharma,John J Magnuson,John Lyons,M Jake Vander Zanden,Howard Browman

doi:10.1371/journal.pone.0022906

Sapna Sharma, John J Magnuson + Show 3 more

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https://doi.org/10.1371/journal.pone.0022906

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Abstract

Species are influenced by multiple environmental stressors acting simultaneously. Our objective was to compare the expected effects of climate change and invasion of non-indigenous rainbow smelt (Osmerus mordax) on cisco (Coregonus artedii) population extirpations at a regional level. We assembled a database of over 13,000 lakes in Wisconsin, USA, summarising fish occurrence, lake morphology, water chemistry, and climate. We used A1, A2, and B1 scenarios from the Intergovernmental Panel on Climate Change (IPCC) of future temperature conditions for 15 general circulation models in 2046–2065 and 2081–2100 totalling 78 projections. Logistic regression indicated that cisco tended to occur in cooler, larger, and deeper lakes. Depending upon the amount of warming, 25–70% of cisco populations are predicted to be extirpated by 2100. In addition, cisco are influenced by the invasion of rainbow smelt, which prey on young cisco. Projecting current estimates of rainbow smelt spread and impact into the future will result in the extirpation of about 1% of cisco populations by 2100 in Wisconsin. Overall, the effect of climate change is expected to overshadow that of species invasion as a driver of coldwater fish population extirpations. Our results highlight the potentially dominant role of climate change as a driver of biotic change.

Highlights

Global biodiversity is threatened by environmental stressors such as climate change, habitat loss, and biological invasions [1]
We predicted the effects of two environmental stressors acting on the local extirpation of a native species
Six cisco populations have been extirpated in recent years, as cisco have not been found despite repeated targeted sampling

Summary

Introduction

Global biodiversity is threatened by environmental stressors such as climate change, habitat loss, and biological invasions [1]. Climate change and biological invasions are two of the foremost threats to aquatic ecosystems [1,3,5]. Global climatic change is expected to alter species distributions, community composition, and ecosystem structure [6,7]. Climate change will have profound impacts on thermal habitat, distribution, and growth of freshwater organisms [8,9,10,11]. Coldwater fishes may lose suitable thermal habitat in the south, but may expand their range northward, and warmwater fish species may expand their range [8,12,13]. The invasion and the northward range expansion of non-indigenous species may have serious consequences for native species [11,14,16] as the invasion of non-indigenous species can have large ecological [15,16,17,18] and economic impacts [19]

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