Demography of Quasipaa frogs in China reveals high vulnerability to widespread harvest pressure

Abstract

Over 20 species of amphibians are being harvested in Asia with local consumption exceeding the volume of international export in some countries. Over-harvesting is a particular concern for large-bodied species as their life history traits often make them prone to population depletion. Quasipaa spinosa is a large, stream-dwelling frog that is considered a delicacy in China. The demand for its meat is high, with domestic trade amounting to USD 32 m in one province alone in one year. Although it is known that populations of Q. spinosa have been heavily depleted, no information on the demography of wild populations has been available to assess declines and vulnerability to ongoing exploitation. We studied Q. spinosa in Hong Kong, China, where populations are protected from hunting and habitat is largely unaltered. Results from a population viability analysis suggest that these populations are highly vulnerable to hunting activity; hunted populations were associated with much lower expected abundance and substantially higher risk of extirpation than populations free from harvesting pressure. Harvesting confers at least 59% reduction of abundance in 5 years. Based on ongoing harvesting of this species from the wild and our determination that relatively low levels of harvesting can lead to population extirpation in the short term, we call for the establishment of protection measures (State Protected Animal status) for this species throughout China and advocate for strengthened enforcement of existing regulations in nature reserves and other protected areas. Some currently harvested amphibians in China, including other species of Quasipaa, are probably similarly threatened by unregulated harvesting activities and we recommend that their status and vulnerability to harvesting be carefully reviewed.