Divergent impacts of warming weather on wildlife disease risk across climates
| Autor: | Samuel D. Spencer, Jason R. Rohr, Olivia Santiago, Jeremy M. Cohen, Erin L. Sauer |
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| Rok vydání: | 2020 |
| Předmět: | |
| Zdroj: | Science |
| ISSN: | 1095-9203 0036-8075 |
| DOI: | 10.1126/science.abb1702 |
| Popis: | INTRODUCTION: Infectious disease outbreaks among wildlife have surged in recent decades alongside global climate change. However, the circumstances under which climate change is most likely to promote or inhibit infectious disease remain unknown for several reasons. First, researchers know little about how climate change will alter disease risk across hosts and parasites with diverse life history traits (e.g., host thermal biology, habitat, and parasite transmission mode). Second, not all parasites will be affected by climate change, but it remains unclear how the relative risk of disease caused by bacteria, viruses, fungi, and helminths is changing. Third, impacts of temperature abnormalities and variability, rather than increasing mean temperatures alone, remain largely unexplored. Finally, it is not clear which regions of the globe may become more amenable to disease and which may become less suitable. RATIONALE: Recently, the thermal mismatch hypothesis has emerged to predict how infection risk is affected by temperature across climate zones in an amphibian-disease system. This hypothesis suggests that hosts adapted to cooler and warmer climates should be at greatest risk of infection under abnormally warm and cool conditions, respectively, because smaller-bodied parasites are more likely to maintain performance over a wider range of temperatures than larger-bodied hosts but are limited by extreme conditions. However, thermal mismatches may not affect diverse hosts and parasites equally because wildlife host and parasite traits can greatly influence disease outcomes. For example, thermal mismatches might exert an especially strong influence over disease outcomes in ectothermic hosts because their immune responses are highly temperature-dependent. To address this challenge, we examined how disease risk was affected by temperature for diverse wildlife hosts and parasites that vary in ecologically important traits across a worldwide climatic gradient. We amassed a global, spatiotemporal dataset describing parasite prevalence across 7346 wildlife populations and 2021 host-parasite combinations. Further, we compiled long-term climate records at each location and short-term weather records during each survey. Our modeling approach investigated how relationships between parasite prevalence and weather depend on local climate and host and parasite traits. Finally, we projected broad-scale changes in disease risk based on thermal mismatches and ensemble climate change model predictions. RESULTS: We found that on average, hosts from cool and warm climates experienced increased disease risk at abnormally warm and cool temperatures, respectively, as predicted by the thermal mismatch hypothesis. This effect was greatest among hosts that are ectothermic and nonmigratory and among systems in which the parasite is directly transmitted (without vectors or intermediate hosts). However, the thermal mismatch effect was similar in terrestrial and freshwater systems. Projections based on climate change models indicate that ectothermic wildlife hosts from temperate and tropical zones may experience sharp increases and moderate reductions in disease risk, respectively, though the magnitude of these changes depends on parasite taxa. Prevalence of helminth parasites increased most in temperate zones, whereas fungal parasite prevalence decreased most in tropical zones. CONCLUSION: Cold-adapted hosts may experience increasing disease risk during abnormally warm periods. Meanwhile, the risk to warm-adapted hosts may increase during cool periods and mildly decrease during warm periods. Further, these effects are dependent on the identity and traits of the parasite and the host. Our results highlight the complexity of the influences of climate change on diverse host-parasite dynamics, whereas our broad-scale predictions suggest contrasting impacts of climate change across climate zones and diverse parasites. As climate change accelerates, hosts adapted to cooler or milder climates may suffer increasing risk of infectious disease outbreaks, whereas those adapted to warmer climates could see mild reductions in infectious disease risk. |
| Databáze: | OpenAIRE |
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