Abstract
Many threats to biodiversity cannot be eliminated; for example, invasive pathogens may be ubiquitous. Chytridiomycosis is a fungal disease that has spread worldwide, driving at least 90 amphibian species to extinction, and severely affecting hundreds of others1,2,3,4. Once the disease spreads to a new environment, it is likely to become a permanent part of that ecosystem. To enable coexistence with chytridiomycosis in the field, we devised an intervention that exploits host defences and pathogen vulnerabilities. Here we show that sunlight-heated artificial refugia attract endangered frogs and enable body temperatures high enough to clear infections, and that having recovered in this way, frogs are subsequently resistant to chytridiomycosis even under cool conditions that are optimal for fungal growth. Our results provide a simple, inexpensive and widely applicable strategy to buffer frogs against chytridiomycosis in nature. The refugia are immediately useful for the endangered species we tested and will have broader utility for amphibian species with similar ecologies. Furthermore, our concept could be applied to other wildlife diseases in which differences in host and pathogen physiologies can be exploited. The refugia are made from cheap and readily available materials and therefore could be rapidly adopted by wildlife managers and the public. In summary, habitat protection alone cannot protect species that are affected by invasive diseases, but simple manipulations to microhabitat structure could spell the difference between the extinction and the persistence of endangered amphibians.
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Data availability
Our data are available through figshare at https://doi.org/10.6084/m9.figshare.23672805 (ref. 46). Source data are provided with this paper.
Code availability
The R code used for our GAMMs is available through GitHub: https://github.com/erinsauer/Waddle-et-al.-Hotspot-shelters.
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Acknowledgements
We thank M. Elphick, B. Ashton, R. Miller, C. Wilson, K. Pasfield and H. Malouf for their assistance with setting up mesocosms; M. Whiting for lending us laboratory space for disease testing; M. Elphick for assistance with data entry and management; V. Russell and S. Deering for their assistance with data collection; and M. Holmes for assistance with visuals. A.W.W. was supported by a Melbourne Research Scholarship, a Graduate Education Scholarship from the American Australian Association, and also supported by the Schmidt Science Fellows, in partnership with the Rhodes Trust; L.F.S. was supported by ARC FT190100462; S.C. was supported by a Macquarie University Research Fellowship; and J.A.F. was supported by ARC DP200100747 and ARC FT210100034. Research funding was provided by Macquarie University. Additional funding was provided by the Frog and Tadpole Study Group of New South Wales, a Royal Zoological Society of New South Wales Ethel Mary Read Student Grant and a Holsworth Wildlife Research Endowment Student Grant.
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Conceptualization: A.W.W., S.C., E.L.S. and R.S. Methodology: A.W.W., S.C., R.S. and E.L.S. Investigation: A.W.W., A.A., H.G., I.D., R.S. and S.W.K. Validation: A.W.W., Y.L., E.L.S. and R.S. Visualization: A.W.W., E.L.S. and Y.L. Funding acquisition: A.W.W., R.S. and S.C. Data curation: A.W.W., C.M., J.A.F., P.T.C., R.S., Y.L. and E.L.S. Writing (original draft): A.W.W. Writing (review and editing): A.W.W., L.F.S., L.B., R.S. and Y.L.
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Extended data figures and tables
Extended Data Fig. 1 Effects of various preferred temperature regimes on chytrid infection.
Infection intensity data for green and golden bell frogs (L. aurea) that were exposed to Bd. Frogs were infected with Bd, held at 19.0 °C for 14 days and then placed at one of three temperatures (26.4 °C, 29.1 °C or 31.0 °C), on the basis of the temperatures selected by those individuals in a previous study.
Extended Data Fig. 2 Effects of heat treatments on chytrid infection intensity and survivorship.
a,b, Infection intensity (a) and survivorship data (b) for green and golden bell frogs (L. aurea) that were exposed to Bd. Heat control frogs (n = 23) were treated with heat and then exposed to Bd, whereas Bd control frogs (n = 23) had no heat treatment before Bd exposure.
Extended Data Fig. 3 Experimental treatments and design of hothouse thermal shelters for the mesocosm study.
a,b, Mesocosm set-up for unshaded greenhouse (a) and shaded greenhouse (b) treatments. c, Brick configuration inside greenhouses. Photo credit A.W.W.
Extended Data Fig. 4 Design of thermal gradients for thermal selection experiments.
Green and golden bell frogs (L. aurea) in thermal gradients. Photo credit A.W.W.
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Waddle, A.W., Clulow, S., Aquilina, A. et al. Hotspot shelters stimulate frog resistance to chytridiomycosis. Nature 631, 344–349 (2024). https://doi.org/10.1038/s41586-024-07582-y
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DOI: https://doi.org/10.1038/s41586-024-07582-y
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