Ecological traits that predict thermal variance also predict thermal tolerance

Background/Question/Methods

Variation in the impact of climate change on population persistence is not only relatedto proximity to the tropics, but also to species traits, especially traits that can buffer individuals from increases in air temperature. Fossorial (burrowing) species are found in most major animal clades, and a common assumption is that these species may experience fewer thermal extremes compared to their surface-dwelling counterparts, buffering them from climate extremes and enhancing climate change resilience. However, theory and data suggest that evolution of thermal performance is closely tied to the extent of thermal variation, where species that evolve under limited thermal variance feature narrow thermal performance limits; classically, this is seen in tropical vs temperate species. We hypothesize that fossorial species evolve narrower thermal tolerance limits, potentially rendering these species more susceptible to climate change

Results/Conclusions

Here we use long-term data to show that increases in summer and fall temperature were associated with a decline of body condition in a fossorial salamander over 12-years. Next, we leverage comparative data on reptiles, amphibians, insects, and mammals from the GlobTherm data base to explore how fossoriality coevolves with thermal traits. Consistent with expectation, we show that fossoriality can be associated with narrower thermal tolerance limits. These findings, coupled with the assumption that burrowing species are poor dispersers, suggest that burrowers may be relatively prone to extinction under climate change.