A new perspective on amphibians under global change: Detecting sublethal effects of environmental stress as agents of silent population declines
Final Report Abstract
This project aimed to evaluate the significance of sublethal effects induced by a combination of environmental stressors associated with global change, such as temperature and pollution stress, in the context of the enigmatic decline of amphibians. Specifically, the project sought to investigate the short-term stress responses and to determine long-term effects of stress exposure in amphibians by analyzing a range of biomarkers, including morphological, physiological, endocrinological, immunological, and genetic proxies for stress. Moreover, the project aimed to assess the acclimation capacity of amphibians stages to changing thermal conditions, through both experimental and meta-analytical approaches. Thereto, we conducted experiments exposing different ontogenetic stages of the common frog (Rana temporaria) to a combination of environmentally relevant nitrate concentrations and rearing temperatures. Our findings highlight that environmental stressors can interact to impact amphibian development, resulting in adverse synergetic effects on growth, health, and survival, with early life stress exposure affecting individuals across life stages. Our results indicate a crucial role of the "stress hormone" corticosterone (CORT) in mediating these downstream effects of environmental stress. In one study, the gut microbiome of amphibian larvae was found to potentially play a central role in buffering the detrimental effects of stress exposure on larval health. However, this buffer capacity was shown to be impaired in combination with thermal stress; this finding was published in the journal Proceedings of the Royal Society B (2024). Additionally, we conducted a systematic review and quantitative analyses on phylogenetic, ontogenetic, and biogeographic patterns in amphibian thermal acclimation capacity. Amphibians show moderate acclimation capacity across life stages, but we revealed biases in taxonomy, biogeography, life stages, and study design. Our findings include methodological recommendations to improve future research. We can conclude that exposure to sublethal environmental stress during early life stages might contribute to the population decline of amphibians through short- and long-term effects on amphibian performance, health, and survival, particularly if exposed to simultaneously occurring stressors. We evaluated waterborne CORT as a non-invasive collection method for assessing baseline and acute stress across amphibian life stages, confirming it as a promising conservation tool, especially in amphibian larvae. So far, the project has produced seven peer-reviewed publications, with additional manuscripts in preparation.
Publications
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09/2022. Timing of parental breeding influences pollution sensitivity in the European common frog (Rana temporaria). Poster presentation. Societas Europaea Herpetologica (Belgrade, SER).
Ruthsatz, Katharina
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Developmental plasticity in amphibian larvae across the world: Investigating the roles of temperature and latitude. Journal of Thermal Biology, 106, 103233.
Sinai, Noa; Glos, Julian; Mohan, Ashwini V.; Lyra, Mariana L.; Riepe, Maya; Thöle, Elena; Zummach, Cecile & Ruthsatz, Katharina
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Timing of parental breeding shapes sensitivity to nitrate pollution in the common frog Rana temporaria. Journal of Thermal Biology, 108, 103296.
Ruthsatz, Katharina; Bartels, Fabian; Stützer, Dominik & Eterovick, Paula C.
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09/2023. Interactive effect of thermic and pollution stress on tadpole gut microbiome. Poster presentation. Societas Europaea Herpetologica (Wolverhampton, UK).
Dr. Eterovick
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Contributions of water-borne corticosterone as one non-invasive biomarker in assessing nitrate pollution stress in tadpoles of Rana temporaria. General and Comparative Endocrinology, 331, 114164.
Ruthsatz, Katharina; Eterovick, Paula C.; Bartels, Fabian & Mausbach, Jelena
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Exploring water-borne corticosterone collection as a non-invasive tool in amphibian conservation physiology: benefits, limitations and future perspectives. Conservation Physiology, 11(1).
Ruthsatz, Katharina; Rico-Millan, Rafael; Eterovick, Paula Cabral & Gomez-Mestre, Ivan
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Life in plastic, it's not fantastic: Sublethal effects of polyethylene microplastics ingestion throughout amphibian metamorphosis. Science of The Total Environment, 885, 163779.
Ruthsatz, Katharina; Schwarz, Anja; Gomez-Mestre, Ivan; Meyer, Ruth; Domscheit, Marie; Bartels, Fabian; Schaeffer, Sarah-Maria & Engelkes, Karolin
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02/2024. Microbiome at the interface between environmental stress and animal health: an example from the most threatened vertebrate group. Oral presentation. II International Symposium on Tadpole Evolution (online).
Eterovick, Paula C.
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07/2024. Navigating ontogenetic pathways: developmental plasticity of amphibians in a warming world. Oral presentation. Society of Experimental Biology Annual Conference (Prague, CZE).
Ruthsatz, Katharina
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11/2024 (upcoming). Amphibian Challenges and Adaptive Strategies in a Changing Climate. Thermal Biology Meeting: Changing Animals in a Changing World. (Lund, SE). Invited keynote talk.
Ruthsatz, Katharina
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Acclimation capacity to global warming of amphibians and freshwater fishes: Drivers, patterns, and data limitations. Global Change Biology, 30(5).
Ruthsatz, Katharina; Dahlke, Flemming; Alter, Katharina; Wohlrab, Sylke; Eterovick, Paula C.; Lyra, Mariana L.; Gippner, Sven; Cooke, Steven J. & Peck, Myron A.
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Living in a multi-stressor world: nitrate pollution and thermal stress interact to affect amphibian larvae. openRxiv.
Sinai, Noa; Eterovick, Paula C.; Kruger, Natasha; Oetken, Ben & Ruthsatz, Katharina
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Physiological responses to a changing winter climate in an early spring‐breeding amphibian. Ecology and Evolution, 14(7).
Schmidt, Robin; Zummach, Cecile; Sinai, Noa; Sabino‐Pinto, Joana; Künzel, Sven; Dausmann, Kathrin H. & Ruthsatz, Katharina
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The microbiome at the interface between environmental stress and animal health: an example from the most threatened vertebrate group. Proceedings of the Royal Society B: Biological Sciences, 291.
Eterovick, Paula Cabral; Schmidt, Robin; Sabino-Pinto, Joana; Yang, Chen; Künzel, Sven & Ruthsatz, Katharina
