Understanding ecological networks by means of advanced environmental measurement technology and development of new environmental conservation strategy

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The main results obtained by this study are as follows.(1) Connectivity of forests was evaluated by calculating a newly proposed index "CON", which is defined as the number of forest grid cells around a central forest grid in a 3×3 grid cell, using a standard grid (approx. 1km grid cell)-based data on vegetation. Distribution of terrestrial mammals was overlain on the forest connectivity. These mammals were classified into four groups according to the reaction of each species to the CON-value : 1) mountain-dwelling mammals, 2) semi-mountain dwelling mammals, 3) hill-dwelling mammals, and 4) mammals showing low reactions to CON-value. The results of our study indicated that the forests in Chugoku district are comparatively fragmented for its forest coverage ratio. The forest connectivity is strongly correlated to topographical factors.(2) Movements of radio-collared black bears (Ursus thibetanus japonicus) were monitored in the Hyounosen Mountain region. By using GIS, their homerange si … More ze, movement pattern and characteristics of habitat vegetation were analyzed.(3) GPS (Global Positioning System)-Collars were attached to one female Sika deer (Cervus nippon) on Kinkazan Island, and to two male black bears (Ursus thibetanus japonicus), one in Hyounosen region and another in Chichibu region. The GPS-collar in Kinkazan Island was successfully recovered and the location data was downloaded. The integrated analysis by GIS showed that the deer seasonally changed its habitat.(4) The migration of Gray-faced Buzzards (Butastur indicus) was satellite-tracked in 1998 and 1999. Wintering habitat of the buzzards was also studied using satellite locations, field observations, and GIS analysis on Ishigaki Island, Okinawa. Three of the ten individuals with PTTs (platform transmitter terminals) were successfully tracked from the wintering sites on Ishigaki and Iriomote Islands, Okinawa, to their breeding sites. Tracking of the autumn migration of one individual was not fully successful, although a part of its migration route could be determined. In spring, the buzzards migrated north along the Ryukyu Islands and the Satsunan Islands. They repeated a migration pattern of single day movements separated by short to long stop-overs on small islands. In winter, the buzzards avoided forests and preferred farmlands and grasslands. Less