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Abstract Climate change might drive species declines by altering species interactions, such as host–parasite interactions. However, few studies have combined experiments, field data, and historical climate records to provide evidence that an interaction between climate change and disease caused any host declines. A recently proposed hypothesis, thethermal mismatch hypothesis, could identify host species that are vulnerable to disease under climate change because it predicts that cool‐ and warm‐adapted hosts should be vulnerable to disease at unusually warm and cool temperatures, respectively. Here, we conduct experiments onAtelopus zeteki, a critically endangered, captively bred frog that prefers relatively cool temperatures, and show that frogs have high pathogen loads and high mortality rates only when exposed to a combination of the pathogenic chytrid fungus (Batrachochytrium dendrobatidis) and high temperatures, as predicted by thethermal mismatch hypothesis. Further, we tested various hypotheses to explain recent declines experienced by species in the amphibian genusAtelopusthat are thought to be associated withB. dendrobatidisand reveal that these declines are best explained by thethermal mismatch hypothesis. As in our experiments, only the combination of rapid increases in temperature and infectious disease could account for the patterns of declines, especially in species adapted to relatively cool environments. After combining experiments on declining hosts with spatiotemporal patterns in the field, our findings are consistent with the hypothesis that widespread species declines, including possible extinctions, have been driven by an interaction between increasing temperatures and infectious disease. Moreover, our findings suggest that hosts adapted to relatively cool conditions will be most vulnerable to the combination of increases in mean temperature and emerging infectious diseases.
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This content will become publicly available on May 1, 2026
Two Hypotheses About Climate Change and Species Distributions
ABSTRACT Species' distributions are changing around the planet as a result of global climate change. Most research has focused on shifts in mean climate conditions, leaving the effects of increased environmental variability comparatively underexplored. This paper proposes two new macroecological hypotheses—thevariability damping hypothesisand thevariability adaptation hypothesis—to understand how ecological dynamics and evolutionary history could influence biogeographic patterns being forced by contemporary large‐scale climate change across all major ecosystems. The variability damping hypothesis predicts that distributions of species living in deep water environments will be least affected by increasing climate‐driven temperature variability compared with species in nearshore, intertidal and terrestrial environments. The variability adaptation hypothesis predicts the opposite. Where available, we discuss how the existing evidence aligns with these hypotheses and propose ways in which they may be empirically tested.
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- Award ID(s):
- 2220927
- PAR ID:
- 10654013
- Publisher / Repository:
- Ecology Letters
- Date Published:
- Journal Name:
- Ecology Letters
- Volume:
- 28
- Issue:
- 5
- ISSN:
- 1461-023X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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