近・現代のニホンイノシシの個体群トレンド  [in Japanese] Population trends of the Japanese wild boar during the Showa era  [in Japanese]

A questionnaire was used to evaluate population trends of Japanese wild boars (Susscrofa leucomystax) in the Showa era (1926-1989). Response was received from 419 branches of the Japan Hunters Association in 35 prefectures. Population trends were classified into 4 phases (increasing, decreasing I, decreasing II and recovering) by changes in wild boar harvest and the index of hunting success of each prefecture. From the period befor WWII (BW) (1926-1942) to the period after WW II (AW) (1946-1959), decreasing trends were found in the southern part of the Kinki district and Shizuoka, Miyazaki and Kochi prefectures where wild boar hunting was prosperous. Increasing trends were found in the other prefectures. From AW to the high economic growth period (HG) (1960-1974) prefectures which previously showed decreasing trends had increased, but from HG to the present (PR) (1975-1989) most prefectures showed decreasing trends. However, increasing trends during the period from HG to PR were found in Gunma and Tottori prefectures of Honshu Island, and Fukuoka, Saga and Oita prefectures of Kyusyu Island. This may be due to the fact that these areas are located at the wild boar dispersal front in each respective island.