神奈川県内における国内外来種ヌマガエル Fejervarya kawamurai の分布

Abstract

Fejervarya kawamurai is naturally distributed in the western part of Honshu, Shikoku, Kyushu, and the Ryukyu islands in Japan. However, in recent years, this species has also been spotted in the Kanto region. The presence of this species has been confirmed in several areas in Kanagawa Prefecture; however, its detailed distribution throughout Kanagawa Prefecture is unknown. In this study, we surveyed the distribution of this species in paddy fields throughout Kanagawa Prefecture. The presence of F. kawamurai was confirmed in Izumi Ward, Totsuka Ward, Sakae Ward, Yokohama city, Fujisawa city, Yamato city, Chigasaki city and Chuo Ward, Sagamihara city. Continuous distribution of this species was confirmed in the paddy fields along the Sakai river and Hikiji-gawa River, which indicates that this species expands its distribution via paddy field areas. However, enclaved introduction sites were identified approximately 16 km away from other introduction sites. This suggests that this species might have invaded each site separately based on anthropogenic factors.