Greater local adaptation to temperature in the ocean than on land

Abstract

Warming threatens biodiversity but there is considerable uncertainty in which species and ecosystems are most vulnerable. Moreover, our understanding of organismal sensitivity is largely centered on species level assessments, which do not consider variation across populations. Here, we used meta-analysis to quantify differentiation in thermal tolerance across 413 populations from 105 species living in terrestrial, marine, and freshwater realms. Strikingly, we found strong differentiation in heat tolerance across populations in marine and intertidal taxa but not terrestrial or freshwater taxa. This is counter to the expectation that increased dispersal potential in the ocean should reduce intraspecific variation. Our findings are consistent with the “Bogert effect” operating in terrestrial but not marine ecosystems, which predicts that behavioral thermoregulation constrains evolution. Such adaptive differentiation in the ocean suggests that there may be standing genetic variation at the species level to buffer climate impacts. Assessments of organismal vulnerability to warming, especially in marine species, should account for variation in thermal tolerance among populations or risk under- or overestimating climate vulnerability.

What's going to be on the menu with global environmental changes?

“…Thermal limits vary greatly between taxa and even among life stages for a given species (Pinsky et al, 2019); fishes have the narrowest temperature tolerance range and are at their most vulnerable during the larval and spawning stages of their life cycle (Dahlke et al, 2020). Generally, marine species show greater variation in heat tolerance compared to terrestrial taxa, a difference linked to an increased capacity for terrestrial species to engage in behavioral thermoregulation and use of microhabitats with varied climatic conditions (Sasaki et al, 2022).…”

Impacts of ocean warming on echinoderms: A meta‐analysis

“…First, the authors were unable to gather sufficient information from studies in order to establish the effect of local scale thermal variability on the vulnerability to warming. Additionally, sufficient data on the spatial distribution of echinoderm species is lacking, and it is possible that responses to ocean warming may differ depending on the breadth of the species thermal range, and whether the individuals were collected from the leading or trailing edges, or the central part of the range (Collin et al, 2018;O'Connor et al, 2012;Poloczanska et al, 2016;Sasaki et al, 2022;Sunday et al, 2011;Zettlemoyer & Peterson, 2021). Some classes of echinoderms were underrepresented in the dataset, specifically there were only 20 data points for ophiuroids, and astonishingly, the authors did not find relevant studies on crinoids during the literature search.…”

“…Marine ectotherms exposed to greater seasonal thermal variability at temperate latitudes for instance often have wider thermal windows and have evolved greater capacity to withstand periods of thermal extremes via enhanced physiological and behavioural thermoregulation (Madeira et al, 2017;Sokolova & Pörtner, 2003;Sunday et al, 2011;Woolsey et al, 2015). This geographic pattern in vulnerability to warming may not always hold true, however, because vulnerability may also be dependent on other spatial factors, including the breadth of the geographic range, the part of the range in which they occur, their depth and habitat (Drake et al, 2017;O'Connor et al, 2012;Pey et al, 2011;Poloczanska et al, 2016;Sasaki et al, 2022;Zettlemoyer & Peterson, 2021).…”