2001 年 5 巻 2 号 p. 119-133
This paper examines the ecological basis for species diversity in a traditional agricultural ecosystem (the 'SATOYAMA') from the viewpoint of conservation ecology and discusses the contemporary significances of the ecosystems. The SATOYAMA, which was a common rural ecosystem before the westernization of Japanese communities, consisted of a mosaic of patches of forests, grasslands, ponds and creeks supplying various resources to support traditional agriculture and village life. The landscape mosaic of the SATOYAMA provided a variety of habitats for wild animals and plants, and contributed to high ß (inter-habitat) diversity. Moderate disturbances and stresses associated with exploitation of plant materials from coppice forests and grasslands, i.e. clearing, mowing, coppicing, burning, and litter removal, prevented competitive exclusion by a few dominant species and enhanced α (intra-habitat) diversity. Abandonment of SATOYAMA ecosystems, which had lost their instrumental value mainly due to the fuel revolution and popularization of chemical fertilizer use, and their destruction due to regional development projects during periods of rapid growth and the bubble economy are partly responsible to the current biodiversity crisis in Japan. From the past management practices of the SATOYAMA, we can learn exemplary forms of ecologically sound 'ecosystem management' and wisdom to avoid the 'tragedy of the commons'. Conserving or restoring SATOYAMA systems by conferring on them new values rather than the past ones, may be vital to overcoming the current biodiversity crisis and ensuring the sustainability of regional communities in harmony with their natural environments.
