Influence of water temperature and biotic interactions on the distribution of westslope cutthroat trout (Oncorhynchus clarkii lewisi) in a population stronghold under climate change

Abstract

Climate warming is expected to have substantial impacts on native trout across the Rocky Mountains, but there is little understanding of how these changes affect future distributions of co-occurring native fishes within population strongholds. We used mixed-effects logistic regression to investigate the role of abiotic (e.g., temperature) and biotic factors (Bull Trout presence, Salvelinus confluentus) on distributions of Westslope Cutthroat Trout (Oncorhynchus clarkii lewisi; WCT) in the North Fork Flathead River, USA and Canada. The probability of WCT presence increased with stream temperature and decreased with channel gradient and Bull Trout presence, yet the effect of Bull Trout was reduced with increasing pool densities. Combining this model with spatially-explicit stream temperature projections, we predict a 29% increase in suitable habitat under high emissions through 2075, with gains at mid-elevation sites predicted to exceed Bull Trout thermal tolerances and high-elevation sites expected to become more thermally suitable for WCT. Our study illustrates the importance of considering abiotic and biotic drivers to assess species response to climate change, helping to guide local scale climate adaptation and management.

Metabolic rate and critical thermal maximumCTmaxestimates for westslope cutthroat trout,Oncorhynchus clarkii lewisi

“…Due to climate change, westslope cutthroat trout may experience shifts in the distributions of their thermal habitat (Williams et al, 2009;Heinle et al, 2021). In order to simulate changes to species distributions and inform recovery strategies and actions, particularly for species at risk, it is important to understand a species' physiology and thermal limits.…”

Global change impacts a threatened species through alteration of predator-prey dynamics

“…Such community approaches are necessary as single-species studies often overlook biotic interactions (such as indirect food web interactions) that are critical for realistic projections 15,16 . While most research has focused on how species distribution and population demography vary with abiotic conditions [17][18][19] , recent work demonstrated that accounting for biotic interactions (such as predation or competition) improves the projection of species responses to change 15,16 . Yet, few studies have examined the combined effect of projected changes in land use and in climate on multi-species trophic interactions 20 .…”

“…Spatiotemporal simulations of community dynamics are a powerful approach to gain a mechanistic understanding of how environmental changes can influence species interactions 13,14 . Such community approaches are necessary as single-species studies often overlook biotic interactions (such as indirect food web interactions) that are critical for realistic projections 15,16 . While most research has focused on how species distribution and population demography vary with abiotic conditions [17][18][19] , recent work demonstrated that accounting for biotic interactions (such as predation or competition) improves the projection of species responses to change 15,16 .…”

Global change risks a threatened species due to alteration of predator–prey dynamics

“…Spatiotemporal simulations of community dynamics are a powerful approach to gain a mechanistic understanding of how environmental changes can influence species interactions (Oliver et al, 2009; Tylianakis et al, 2008). Such community approaches are necessary as single‐species studies often overlook biotic interactions (such as indirect food web interactions) that are critical for realistic projections (Heinle et al, 2021; Trainor & Schmitz, 2014). While most research has focused on how species distribution and population demography vary with abiotic conditions (Bonnot et al, 2018; Dainese et al, 2017; Zurell et al, 2018), recent work has demonstrated that accounting for biotic interactions (such as predation or competition) improves the projection of species responses to change (Heinle et al, 2021; Trainor & Schmitz, 2014).…”

“…Such community approaches are necessary as single‐species studies often overlook biotic interactions (such as indirect food web interactions) that are critical for realistic projections (Heinle et al, 2021; Trainor & Schmitz, 2014). While most research has focused on how species distribution and population demography vary with abiotic conditions (Bonnot et al, 2018; Dainese et al, 2017; Zurell et al, 2018), recent work has demonstrated that accounting for biotic interactions (such as predation or competition) improves the projection of species responses to change (Heinle et al, 2021; Trainor & Schmitz, 2014). Yet, few studies have examined the combined effect of projected changes in land use and in climate on multispecies trophic interactions (Bossier et al, 2021).…”