Incorporating evolutionary insights to improve ecotoxicology for freshwater species

Abstract

Ecotoxicological studies have provided extensive insights into the lethal and sublethal effects of environmental contaminants. These insights are critical for environmental regulatory frameworks, which rely on knowledge of toxicity for developing policies to manage contaminants. While varied approaches have been applied to ecotoxicological questions, perspectives related to the evolutionary history of focal species or populations have received little consideration. Here, we evaluate chloride toxicity from the perspectives of both macroevolution and contemporary evolution. First, by mapping chloride toxicity values derived from the literature onto a phylogeny of macroinvertebrates, fish, and amphibians, we tested whether macroevolutionary relationships across species and taxa are predictive of chloride tolerance. Next, we conducted chloride exposure tests for two amphibian species to assess whether potential contemporary evolutionary change associated with environmental chloride contamination influences chloride tolerance across local populations. We show that explicitly evaluating both macroevolution and contemporary evolution can provide important and even qualitatively different insights from those obtained via traditional ecotoxicological studies. While macroevolutionary perspectives can help forecast toxicological end points for species with untested sensitivities, contemporary evolutionary perspectives demonstrate the need to consider the environmental context of exposed populations when measuring toxicity. Accounting for divergence among populations of interest can provide more accurate and relevant information related to the sensitivity of populations that may be evolving in response to selection from contaminant exposure. Our data show that approaches accounting for and specifically examining variation among natural populations should become standard practice in ecotoxicology.

Thermal evolution offsets the elevated toxicity of a contaminant under warming: A resurrection study in Daphnia magna

“…This is because the strong selection imposed by these stressors can lead to rapid evolutionary changes (Hendry, 2016). Rapid evolution increasing the tolerance to warming (e.g., Geerts et al., 2015; Ljungfeldt, Quintela, Besnier, Nilsen, & Glover, 2017) and to contaminants (e.g., Brady et al., 2017; Turko, Sigg, Hollender, & Spaak, 2016) has indeed been reported. Yet, despite the increasing concern for interactions between warming and contaminants, we do not know how rapid evolution in response to warming changes the toxicity of contaminants at higher temperatures.…”

“…This is because the strong selection imposed by these stressors can lead to rapid evolutionary changes (Hendry, 2016). Rapid evolution increasing the tolerance to warming (e.g., Geerts et al, 2015;Ljungfeldt, Quintela, Besnier, Nilsen, & Glover, 2017) and to contaminants (e.g., Brady et al, 2017;Turko, Sigg, Hollender, & Spaak, 2016) has indeed been reported.…”

“…Hence, whether organisms can locally survive under warming depends not only on their ability to cope with the increasing temperature, but also on their ability to deal with the elevated toxicity of contaminants at higher temperatures. To understand the impact of both warming (Stoks, Geerts, & De Meester, 2014) and contaminants (Brady, Richardson, & Kunz, 2017), an evolutionary perspective is important. This is because the strong selection imposed by these stressors can lead to rapid evolutionary changes (Hendry, 2016).…”

“…To understand the impact of both warming (Stoks, Geerts, & De Meester, 2014) and contaminants (Brady, Richardson, & Kunz, 2017), an evolutionary perspective is important. This is because the strong selection imposed by these stressors can lead to rapid evolutionary changes (Hendry, 2016).…”

A review of the species, community, and ecosystem impacts of road salt salinisation in fresh waters

“…to high road salt concentrations over multiple generations may underestimate the sensitivity of naïve individuals in uncontaminated systems (also seeBrady, Richardson, & Kunz, 2017).…”