Attention to invasive risk of American bullfrog for Hainan Island.

The invasion of bullfrog(Lithobates catesbeianus) has become one of the main factors leading to native amphibian population decline and extinction.Bullfrog has distributed widely in China,but no any record in Hainan.In the duration of February to April in 2011,eight adult bullfrogs(including 1 pregnancy) were captured in three locations around Shazhou Island at Wanquan River,Hainan.The habitat bullfrogs were captured had the following characteristics: ① soil was mud or sand,② distance from water about 0.5-1.5 m,③ overall slope as 6°-25°,④ vegetation coverage between 75% and 90%,and ⑤ native amphibian species were abundant around location.The bullfrog has been sold at local market and about 120 individuals were traded each day.Bullfrog found in Wanquan River may come from breeding escape or wildlife released by Buddhist.More survey is required to identify whether the breeding population has been built in the study area.