Drivers and uncertainties of forecasted range shifts for warm-water fishes under climate and land cover change

Abstract

Land cover is an important determinant of aquatic habitat and is projected to shift with climate changes, yet climate-driven land cover changes are rarely factored into climate assessments. To quantify impacts and uncertainty of coupled climate and land cover change on warm-water fish species’ distributions, we used an ensemble model approach to project distributions of 14 species. For each species, current range projections were compared to 27 scenario-based projections and aggregated to visualize uncertainty. Multiple regression and model selection techniques were used to identify drivers of range change. Novel, or no-analogue, climates were assessed to evaluate transferability of models. Changes in total probability of occurrence ranged widely across species, from a 63% increase to a 65% decrease. Distributional gains and losses were largely driven by temperature and flow variables and underscore the importance of habitat heterogeneity and connectivity to facilitate adaptation to changing conditions. Finally, novel climate conditions were driven by mean annual maximum temperature, which stresses the importance of understanding the role of temperature on fish physiology and the role of temperature-mitigating management practices.

Current distributions and future climate‐driven changes in diatoms, insects and fish in U.S. streams

“…Freshwater ecosystems are especially vulnerable to global change because they maintain inordinately high diversity while comprising very little of the surface area of the Earth (Dudgeon et al, 2006;Heino et al, 2009;Reid et al, 2019). Despite this recognition, species distribution modelling has been heavily biased towards terrestrial systems (Soininen & Luoto, 2014) and only recently has there been consideration of environmental responses of aquatic insects (Domisch et al, 2013;Kuemmerlen et al, 2015), fish (Bouska et al, 2019;Buisson & Grenouillet, 2009;Radinger et al, 2016) and diatoms (Pajunen et al, 2016). However, simultaneous analyses of distributions across multiple trophic levels is still rare in aquatic systems (but see Soininen et al, 2013).…”

“…The most comprehensive climate change projections of fish distributions in the USA were developed before RCPs (Eaton & Scheller, 1996;Mohseni et al, 2003). Recently, RCPs were explored for 14 warm-water fish species in the central USA (Bouska et al, 2019), but RCP-based projections are still needed for more species. Likewise, the effects of warming and hydrological change were examined for aquatic insects in reference streams in the western USA (Pyne & Poff, 2017), but projections are still required for broader environmental gradients and using RCPs.…”

Effects of climate change on the life stages of stream‐dwelling brown trout (Salmo trutta Linnaeus, 1758) at the rear edge of their native distribution range

“…In the context shown, the effectiveness of different measures that could mitigate the undesirable effects expected should be rigorously assessed (Bouska, Whitledge, Lant, & Schoof, 2019; Fabris, Malcolm, Buddendorf, & Soulsby, 2018; O'Briain, Shephard, Matson, Gordon, & Kelly, 2020; Trimmel et al, 2018). In the case at hand, and among the main and potentially effective management measures, increasing shading could be an applicable one; however, our rivers are intensely shaded and it only would be applicable in specific sites leading to a limited impact.…”