コンゴ, ヌアバレ=ンドキ国立公園に生息するゴリラ (<i>Gorilla gorilla gorilla</i>) の密度推定と集団編成の特徴 Population density and group organization of gorillas (<i>Gorilla gorilla gorilla</i>) in the Nouabalé-Ndoki National Park, Congo
The population density of western lowland gorillas in the Nouabalé-Ndoki National Park, northern Congo, was estimated both by the “bed-census” method and the “counting” method based on bed-count and direct observation. The density was calculated as 1.92-2.56animals/km<sup>2</sup> and 2.29-2.61 animals/km<sup>2</sup> respectively. Because this was the first time to attempt the “bed-census” method in the Ndoki forest, direct comparison of population density was possible between western lowland gorilla populations at all study sites. It was concluded that the density of the Ndoki gorillas was highest. High population density of the Ndoki gorillas was considered to be possible because they have access to a wide repertoire of foods such as highly nutritious terrestrial herbaceous vegetation (THV) and various kinds of fruits and seeds, corresponding to the seasonal fluctuation of food availability. Although the feeding habits and habitat were different between western and eastern gorillas, they shared a basically one-male group composition, large group size, and unit groups that largely shared their home ranges with each other.
アフリカ研究 1994(44), 29-45, 1994