THE ECOLOGICAL GEOGRAPHY OF THE WILD BOAR IN THE SOUTH-EASTERN AREA OF HIROSHIMA PREFECTURE

Abstract

An investigation was conducted into the distribution of wild boars in the southeastern area of Hiroshima Prefecture. In the prefecture, we can see a striking outflow of population from the mountainous areas to the urban areas. The damage of wild animals such as wild boars or monkeys has become one of the causes that brought about depopulation, and in the southeastern area, it has been very severe. These situations have been caused by a breakdown of the ecological balance between men and wild animals, and an approach from the geographical field in which man and man's environment is the main theme is expected to be necessary. Such approach is few and far between in the Japanese geographical field, the author has conducted an investigation into these situations, in the concrete, distributional maps of the wild boars were prepared and investigations into the damage of wild boars and backgrounds of fluctuations of wild boars were conducted. Futhermore, the author hopes that this research will become foundations to project on synthetic management of forests in due consideration of wild animal's conservation. Generally, the wild boar's distribution is regulated by a topographical condition and a vegetation, but in Japan where we have high population density and extensive forest-use we must not ignore the direct and indirect influence by men. In the investigation of the southeastern area in Hiroshima Prefecture, the author points out two types of the distribution as follows; 1) Before the World War II there was a fair distribution of wild boars in the state forest, but there after they decreased in number. 2) Before the World War II, wild boars did not inhabit in the privately owned forest, but from that onwards they became to have habitats there and increased in number. After about 1970, they began to decrease. Firstly, the author refered to the topographical condition in analyzing these distributions, but in this area there was no significance. Next, consideration was given to the vegetation, with the result that it was the important factor influencing the distribution. The difference In management between the state forest and the privately owned forest has produced the difference in the distribution, namely changes in the forest-use have influenced the vegetation and regulated the distribution of wild boars. Under these situations, depopulation has broken out in the latter. The increase of the damage of wild boars has stimulated the elimination's system and with the introduction of the wireless and the superior hound, wild boars have begun to decrease. In short, the distribution of wild boars is influenced largely by man. In future, the effective management of forests in due consideration of wild animal's conservation has to be projected.