イノシシ,クマ類およびシカの捕獲数の変動

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Through the analysis on the official records from 1953 to 1974 of fiscal year, it can be pointed out that the total numbers, hunted with any purpose, of the wild boars, the bears and the deer increased in Japan. Both a linear regression (H=A+Bx) and an exponential increasing (1n (H+l) =1n ( (a+1) +bx) are well fitted in each species, and their increasing rates (B and b) are considerably high as compared with their natural birth rates. The author makes an attempt to find which prefectures have much trend of increasings. On each species, the average hunted number (H) and standard deviation (SD) of each prefecture is arranged on a line in logarithmic graphs. As to the wild boars, less increase rates, and samely smaller coefficients of variation, occur in higher hunted density regions, and greater rates do in the peripheries of the geographical distribution of the animals. The bears were hunted throughout all seasons as the harmful animals on forestory. In central Japan, more animals are hunted, but the trend of increasing is rather small. In north-east region and coastal prefectures of Japan Sea, very high rates of increasing are seen among the hunted numbers of the animals. Huntings of the sika deer are or were under strict limitation in some prefectures. The total numbers hunted in Japan, however, gradually increased. The curve of five-year moving average in logarithmic graph of each prefecture can be classified into five patterns. It shows nearly stationary in eight prefectures, and increases linearly in nine, convexly in four, and concavely in five. Decreasing patterns occur in seven prefectures, in which include those caused by hunting limitation. No geographical arrangement among these patterns is found.

イノシシ,クマ類およびシカの捕獲数の変動

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