'SATOYAMA' and Biodiversity Conservation : 'SATOYAMA' as Important Insect Habitats

抄録

 A 'SATOYAMA' is an ecosystem with frequent but undestructive exploitation and intervention by farmers in rural areas of Japan, and is characterized by a mosaic of (1) Quercus-or Pinus-dominated secondary forests, (2) Miscanthus- or Zoysia-dominated grasslands, (3) cultivated fields and gardens, (4) paddy fields, and (5) creeks and ponds. The ecosystem was maintained in traditional agricultural life, mainly by three types of disturbances, i.e., (1) pruning, mowing and weeding, (2) burning, and (3) irrigation and drainage management. These disturbances used to be ubiquitous also in natural ecosystems as (1) grazing by deer, (2) fires caused by eruptions of volcanoes and (3) flooding of rivers. Thus, the biodiversity of SATOYAMA has its origin in the natural habitats of severely-grazed forests, volcanic grassland, and wetlands on flood plains. The SATOYAMA ecosystem, endowed with these diverse microhabitats, harbors high diversity of insects. The insect fauna is characterized by high diversity and abundance of (1) moths associated with Quercus trees, (2) lycaenid canopy butterflies associated with Quercus trees, (3) anthophilous insects associated with spring ephemeral perennials on the forest floor, (4) insects attracted to resin, (5) cicadas associated with young trees, (6) butterflies associated with grassland plants, (7) insects associated with wetland plants, and (8) aquatic insects living in various aquatic habitats. The high biodiversity and complicated networks among plants and animals, contributing to the stability of herbivore population dynamics, should be conserved as an ecosystem covering various microhabitats by traditional and undestructive use of the land.