Changes in the distribution of the alien Amur hedgehog (Erinaceus amurensis) in Ito City, Shizuoka Prefecture and Odawara City, Kanagawa Prefecture, Japan

Abstract

We investigated the distribution of the alien Amur hedgehog in Ito City, Shizuoka Prefecture and Odawara City, Kanagawa Prefecture. Study methods were 1) capture using cage traps, 2) searching at night, and 3) survey by interview and analysis of existing information. In Ito City, the hedgehog was discovered in 1995 for the first time, and the accumulated distribution area in 2017 was approximately 61 km² (61 of 3rd Area Grid of the Grid Square System), expanding largely concentrically except in mountainous and urban areas. In Odawara City, it was found first in 1987, and the accumulated distribution area in 2009 was approximately 7 km² (seven of 3rd Area Grid) without clear spreading tendency. Based on the information from residents, we consider that the range expansion may be caused partly by artificial transportation.