共存域におけるゴリラとチンパンジーの現状と保護

抄録

The distribution of gorillas and chimpanzees overlaps extensively in eastern Zaire. A similar density is estimated for the 2 kinds of ape in lowland tropical forests, while the density is higher for gorillas than for chimpanzees in montane forests. These differences are reflected in their food selection and range utilization in both habitats. Like chimpanzees, gorillas tend to eat many kinds of fruit and to consume insects regularly in lowland forests. Gorillas and chimpanzees tend to select different food items and to range in different vegetation types in montane forests. The low availability of fruits in montane forests may be responsible for the low density of chimpanzees. When availability of fruits declines, the 2 kinds of ape adopt different strategies. Gorillas exhibit folivorous characteristics and decrease day journey length. Chimpanzees are always extensive frugivores and may possibly increase their ranging area. These findings of their ecological characteristics must be considered in conservation planning. Kahuzi-Biega National Park (6, 000km²) includes both montane and lowland forests and provides a variety of habitats for gorillas and chimpanzees. The recent census conducted in montane forests indicates a slight increase of gorilla population in this decade. However, gorillas and chimpanzees tend to concentrate their ranging in the small areas which are well protected by the Park. The increasing human population around the Park has gradually destroyed the ape's habitats everywhere. Recent developments in tourism and organization of NGO contribute financial supports for the country and knowledge to the local people to realize the value of their natural resources. More international attention is needed to increase conservation activities and to protect fauna and flora from the hazards of human disturbances in this area.