Diversity and rarity hotspots and conservation of butterfly communities in and around the Aokigahara woodland of Mount Fuji, central Japan

摘要

In central Japan, Aokigahara woodland is considered to be one of the most natural areas around Mount Fuji and a core area in the conservation of the biodiversity of Mount Fuji. We chose butterflies as an indicator species of biodiversity and examined six communities in and around the woodland in 2000 using transect counts to examine and search for diversity and rarity hotspots and their associated landscapes. The results showed that butterfly species richness and species diversities H′ 1/λ were significantly higher in forest-edge sites than in forest-interior and/or open-land sites, and variation in the total number of species among these three landscape types was well accounted for by ecologically specialist species, such as landscape specifics, oligovoltines, narrow diet feeders and low-density species. Thus, the species regarded as vulnerable to extinction, including Red List species, were observed more often in forest-edge sites than in forest-interior and/or open-land sites. As a result, in the study area, diversity and rarity hotspots were found in forest-edge landscapes. The reasons why butterfly diversity and rarity hotspots were established in forest-edge landscapes were analyzed and interpreted from several points of view, including disturbance level, landscape elements and plant species richness. From these results, and the fact that some species were confined to forest-interior sites, we conclude that it is very important to conserve and manage forest-edge habitats (considered to be semi-natural) as well as forest-interior habitats (considered to be the most natural) to maintain the diversity of butterfly communities and preserve the various types of threatened species in and around the Aokigahara woodland.