Mitigating the effects of climate change, emerging disease and invasive species on native amphibian populations in the UK

Amphibians are the most threatened group of vertebrates, with global declines driven by and associated with emerging infectious disease, invasive species and climate change (North et al. 2015; O'Hanlon et al. 2018; Pounds et al. 2006). Two emerging infectious diseases severely impacting amphibian populations are chytridiomycosis, caused by a novel lineage of the fungus Batrachochytrium dendrobatidis (Bd; O'Hanlon et al. 2018), and ranavirosis, caused by a group of viruses from the Iridoviridae family (Price et al. 2014). To mitigate emerging disease-driven amphibian declines, we need to understand host-pathogen interactions. Key to pathogen success are reservoir hosts which serve as a pathogen source, but do not develop any signs of the diseases (Garner 2018). These reservoir host are a consistent source of the infective stage of pathogens when the susceptible amphibian host populations decline and are pushed towards extinction; in many cases these reservoir hosts are invasive amphibian species.

Wales, UK, has an ideal amphibian system to study these host-pathogen interactions, with both native, declining populations of amphibians as well as newly discovered smooth and alpine newts, which are an invasive species to the area. Climate change has already affected ranavirus disease dynamics in wild frogs, but it is currently unknown how future changes will affect disease dynamics in other hosts, or how amphibian community composition will impact outcomes (Price et al. 2018).