Ford et al. (2020) synthesize the progress towards understanding threats to amphibians and outline a framework for advancing amphibian conservation. Numerous potential drivers of declines have been explored over the years, with some causes like UV-b radiation, acid rain, and limb deformities ultimately being unsubstantiated. Interestingly, while habitat loss and degradation are likely the largest drivers of amphibian declines, little work has actually directly explored the effects of these threats on global amphibian declines. Critically, most declines are likely the result of additive or interacting effects of multiple threats, and yet these multifarious effects are rarely considered. For example, in the Sierra Nevada of California, Yellow-legged frogs (Rana muscosa and R. sierrae) initially declined due to introduced trout predation and then subsequently were impacted by disease. In general, widespread pathogens like the amphibian chytrid fungus (Batrachochytrium dendrobatidis) are unlikely to be the primary cause of decline but likely often impact populations after other environmental changes or stressors has taken hold. Perhaps most importantly, while we have a wealth of information on possible threats to amphibians, the evidence for solutions to these problems are relatively limited. Ultimately, effective policy from local to national and international scales must incorporate amphibians explicitly if conservation efforts are to be effective.
