Distribution of the Introduced Japanese Marten (Martes melampus) and Its Predation on Indigenous Species on Kuchinoshima, Tokara Islands, Japan

Abstract

The weasel was introduced to Kuchinoshima Island, one of Japan’s Tokara Islands, in the past, for rat control. Recently, the distribution of the Japanese marten, instead of the weasel, was confirmed. Camera trapping (53 cameras, total 3,792 days) and fecal DNA species identification (n=52) were performed, identifying only the marten. The weasel was estimated to be none or at very low population density. The density of the marten feces, 14 feces/km, was higher than that in other areas, suggesting that the population density of the marten was also relatively high. Frequency of occurrences of lizards, earthworms, and land mollusks in the feces (n=1,144) was higher than those in other areas. If the populations of these prey animals were small, they would become threatened by the marten. Subsequent monitoring of the island’s indigenous fauna is considered urgent.