拡大造林地域におけるカモシカ食害対策とその評価

Abstract

具体的事例を通し, 林業とカモシカ保護とを両立させる対策として, 防護柵の評価を行った。研究は滋賀県甲賀郡土山町を対象とした。17の防護柵について調査したところ, 完全に近い防除効果があるもの, 20％程度の効果があるもの, ほとんど効果が見られないものの3タイプが見られた。効果のない柵は奥地に集中して見られた。森林所有者はその効果に大体満足しているが, 設置費用が60万円/haと高額で, 地元に対する大きな負担となっている。カモシカ保護地域は, 林業との関係でカモシカの保護に適するように設定されておらず, 当面の間は防護柵を中心とする対策が両立のために適していると考えられた。

Wildlife conservation is now becoming one of the important problems from the view point of both nature conservation and resource use. In Japan, Japanese serow (Capricornis crispus) has been designated as a Special Natural Monument and prohibited from being hunted and used in any way since 1955. But the damage by serow to crops and young plantation has become social problem since about 1975. Among various protective means, fences are considered as most efficient measure to reconcile timber production and serow conservation. This study clarifies the actual state of fencing system and compares the efficiency as the solution with othermeans. The study area is Tsuchiyamacho in Siga prefecture, which located in the south of Suzuka range. The damage by serow became social problem from about 1965, and protective fences have been constructed by the local administration agency with subsidy from the Agency for Cultural Affairs. The effectiveness of 17 fences are investigated. 3 fences of them builted around the plantation at remte forests don't have any effect at all. But others serve to keep damage rate lower than 20%. The protected area is about 100 hectare and the total cost amounts 56, 560, 000 yen in 1984, which means the unit cost is 600, 000 yen par hectare. However landowners think it too expensive to bear for themselves. Serow protection area is now planed to establish over the Suzuka range. But in Tsuchiyamacho, the area is divided into so small sections that it can't achieve it's purpose.