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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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Looking to aquatic species for conservation farming success
Abstract Thousands of species worldwide are threatened with extinction due to human activities. For some animals, such as elephants, totoaba, and bluefin tuna, population declines are largely driven by hunting. High prices and large profits create a strong incentive for illegal hunting, even in the face of penalties and strict international restrictions against trade. One innovative solution to help reverse the declines of such species is to farm them to increase supply, thereby reducing prices and decreasing hunting incentives. However, this idea has been criticized as impractical, though some examples exist of successful implementation. Here, we evaluate the hurdles facing endangered species farming as a market‐based mechanism to reduce illegal harvest of wild populations and provide guidance on when it is most likely to be effective. Using a simple model, we show how farming costs and enforcement of anti‐poaching measures are key drivers of success for this solution. We also argue that many of the most promising candidates are aquatic species that have been largely overlooked. Thus, while conservation farming may not be a solution for all endangered species, it should be more seriously considered for species that could be produced quickly and cost‐effectively.
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- Award ID(s):
- 1759559
- PAR ID:
- 10459588
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- Conservation Letters
- Volume:
- 12
- Issue:
- 6
- ISSN:
- 1755-263X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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