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oai:figshare.com:article/34018374 2026-09-30T05:43:46Z category_26884 portal_959 item_type_8 month_year_09_2026

From Coal-Mines to Wildfires: Amphibians as Sentinels of Pollution in Freshwater Ecosystems Shannon W. Kaiser (11818442) Bioavailability and ecotoxicology Coal-mine wastewater Environmental contamination Amphibian disease Chytridiomycosis Behavioural ecotoxicology Long-term fire retardant Phos-Chek MVP-Fx Freshwater ecosystems Fire management Water quality <p dir="ltr">Freshwater ecosystems are increasingly shaped by a myriad of anthropogenic stressors. Two of these—fossil-fuel extraction and climate-amplified wildfire—can both result in pollutants being transported through catchments and, in so doing, alter water quality and impact the health and survival of aquatic biota. Amphibians are particularly sensitive to these challenges because of their permeable skin, unshelled eggs, and aquatic larvae, making them effective indicators of emerging environmental stress. With approximately 41% of amphibian species threatened globally, determining how pollutants influence amphibians is essential for understanding and mitigating biodiversity loss.</p><p dir="ltr">This thesis examines amphibians as potential high-resolution sentinels of Anthropocene pollution and integrates field surveys, environmental chemistry, disease ecotoxicology, and controlled laboratory experiments to assess two contaminant sources: coal-mine wastewater and aerially deployed mono- and di-ammonium phosphate-based long-term fire retardant—Phos-Chek MVP-Fx. Together, these chapters link realistic exposure pathways to biologically meaningful outcomes across multiple organisational scales, including survival, growth, developmental synchrony, disease load, antipredator responses, and food-associated behaviour.</p><p dir="ltr">Chapter 1 investigates streams in Royal National Park, New South Wales, Australia, and shows that coal-mine discharge produces persistent and ecologically consequential changes in water chemistry, including elevated electrical conductivity, pH, temperature, and reduced oxidation-reduction potential. Within these altered conditions, stream-breeding frogs exhibited higher chytrid infection loads, with symptomatic and dead individuals observed only at contaminated sites, indicating that mine pollution may act not only as a chemical stressor but also as a catalyst for increased disease risk in wild populations.</p><p dir="ltr">Chapters 2 and 3 examine the ecological effects of Phos-Chek MVP-Fx, which is a fire retardant that is widely used in Australia and comparable to retardants deployed globally to control wildfires. Amphibian larvae of two species, Limnodynastes peronii (Chapter 2) and Ranoidea aurea (Chapter 3), were exposed to treatments over a 96 h pulse exposure. Water quality was consistently altered in fertiliser-like ways, including acidification, oxygen depletion, and increased electrical conductivity, turbidity, and nutrient concentrations. In L. peronii, these changes reduced short-term survival at higher concentrations and produced persistent sublethal effects on growth and behaviour. Similar declines in short-term survival alongside pronounced effects on growth trajectories, developmental synchrony, and activity budgets were also observed in Ranoidea aurea—which is endangered in New South Wales and Vulnerable nationally—with findings consistent with physiological stress and altered energy allocation.</p><p dir="ltr">Collectively, this thesis shows that contemporary pollutants rarely act through a single pathway; instead, mixtures of nutrients, ions, and associated constituents generate coupled lethal and sublethal effects that may not be captured by conventional water quality thresholds alone. The findings support amphibian-sensitive monitoring practices and regulation of mine-affected waterways, and strengthen the case for precautionary wildfire-management practices that consider retardant impacts near aquatic habitats, particularly those supporting vulnerable species. By combining field evidence with mechanistic experimentation, this thesis provides a transferable framework for anticipating and managing under-recognised freshwater impacts of pollution in a rapidly changing world.</p> 2026-09-30T05:43:46Z Text Thesis 10.25949/34018374.v1 https://figshare.com/articles/thesis/From_Coal-Mines_to_Wildfires_Amphibians_as_Sentinels_of_Pollution_in_Freshwater_Ecosystems/34018374 In Copyright