Examining the effects of climate change and species invasions on Ontario walleye populations: can walleye beat the heat?

Abstract

Aim The combined effects of multiple environmental stressors continue to threaten global biodiversity, yet predicting how biotic interactions between native and invasive species may change across a landscape in a multiple stressor environment is relatively understudied. We aim to identify how the invasion of smallmouth bass (Micropterus dolomeiu) may influence native walleye (Sander vitreus) populations across Ontario lakes at the landscape scale in a changing climate. Location Ontario, Canada. Methods Using a database that included the abundance and occurrence of over 130 fish species, lake chemistry and lake morphology for 722 lakes, a redundancy analysis was conducted to identify environmental conditions preferred by walleye and smallmouth bass. Multiple linear regression models were then developed to identify the relationship between walleye and multiple stressors (including climate change and biotic interactions with invasive species). Using future scenarios of climate change, we were then able to project future walleye–smallmouth bass co‐occurrences. Results Smallmouth bass were found to prefer different environmental conditions than walleye; however, when walleye and smallmouth bass were found in the same lakes, walleye abundance was reduced almost threefold. Multiple regression models further suggested that there are fewer walleye in lakes with smallmouth bass. Subsequently, we predicted that under future scenarios of climate change the overlapping co‐occurrence of walleye and smallmouth bass may increase by 86–332% by the year 2070. Main conclusions We illustrate the importance of including multiple environmental stressors in statistical models when attempting to understand how native species will be impacted by invasive species and climate change. While independently climate change is anticipated to lower walleye abundances across Ontario, this change is expected to be exacerbated by invasions of warmwater predators.

Flexible Classification of Wisconsin Lakes for Improved Fisheries Conservation and Management

“…For example, Walleye were uniformly more abundant in cool lakes (and were most abundant in two-story lakes), a pattern consistent with other research on the species (Jobling 1981;Van Zuiden and Sharma 2016;Hansen et al 2017;Rypel et al 2018). For example, Walleye were uniformly more abundant in cool lakes (and were most abundant in two-story lakes), a pattern consistent with other research on the species (Jobling 1981;Van Zuiden and Sharma 2016;Hansen et al 2017;Rypel et al 2018).…”

“…Key patterns were uncovered in the relative abundance, sizestructure and growth rates of focal fish species. For example, Walleye were uniformly more abundant in cool lakes (and were most abundant in two-story lakes), a pattern consistent with other research on the species (Jobling 1981;Van Zuiden and Sharma 2016;Hansen et al 2017;Rypel et al 2018). Unlike previous research (Ryder 1977;Lester et al 2004), water clarity was not a major driver of Walleye abundance patterns within cool lakes.…”

Limnology and Oceanography Bulletin Volume 27 Number 4 November 2018 103–140

“…For example, one of the most recognizable aquatic invasive species, zebra mussels (Dreissena polymorpha), have dramatically altered the food-webs in invaded lakes and shifted production away from pelagic phytoplankton to benthic production dominated systems (Strayer 2010). The arrival of warm-water invasive fish species such as small mouth bass also significantly decreased the occurrence of cool-water species such as walleye (Sander vitreus), by as much as three times (Van Zuiden and Sharma 2016). At present, it is unknown how climate change, intensified land use practices, and invasive species may interact, or even if managers and the public are aware of the multifaceted threats to inland waters.…”

Prairie Lakes: Model Systems for Integrating Ecology and Human Dimensions for Better Management

“…For example, one of the most recognizable aquatic invasive species, zebra mussels ( Dreissena polymorpha ), have dramatically altered the food‐webs in invaded lakes and shifted production away from pelagic phytoplankton to benthic production dominated systems (Strayer ). The arrival of warm‐water invasive fish species such as small mouth bass also significantly decreased the occurrence of cool‐water species such as walleye ( Sander vitreus ), by as much as three times (Van Zuiden and Sharma ). At present, it is unknown how climate change, intensified land use practices, and invasive species may interact, or even if managers and the public are aware of the multifaceted threats to inland waters.…”