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About the Authors:
Sapna Sharma
* E-mail: [email protected]
Affiliation: Center for Limnology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
M. Jake Vander Zanden
Affiliation: Center for Limnology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
John J. Magnuson
Affiliation: Center for Limnology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
John Lyons
Affiliation: Wisconsin Department of Natural Resources, Madison, Wisconsin, United States of America
Introduction
Global biodiversity is threatened by environmental stressors such as climate change, habitat loss, and biological invasions [1]. Forecasting the effects of environmental stressors has received attention in recent years and suggests that a single environmental stressor can lead to the local extirpation of native species (e.g., [2]–[4]). 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]–[11]. Under climate change scenarios, coldwater fishes may lose suitable thermal habitat in the south, but may also 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]–[18] and economic impacts [19].
Coldwater fishes, such as cisco [Corgeonus artedii] require cold water temperatures, high dissolved oxygen concentrations, and oligotrophic conditions, and thereby are sensitive indicators of environmental change [20]. In Wisconsin, cisco are close to the southern edge of their range and are listed as a species of special concern [21]–[22]. Cisco live in larger and deeper inland lakes with cold, well-oxygenated deep waters [21], [23]–[24]. Under climate change scenarios, as air temperatures increase, epilimnion and hypolimnion water temperatures are expected to increase [8], [25]–[26]. As water temperatures increase, the duration of the lake stratification period is expected to increase, isolating the deep waters from exchanges with the atmosphere, making it more likely that metabolic activity will reduce dissolved oxygen concentrations in the hypolimnion to stressful or lethal levels [27]–[29]. The combination of warmer water temperatures and lower dissolved oxygen concentrations under climate change scenarios...