御蔵島における鳥類の垂直分布

概要

論文の詳細を見る
The elevational gradient of species richness is often asserted to mirror the latitudinal gradient, and a monotonic decline in species richness with increasing elevation has been traditionally assumed. On the other hand, it has also been claimed that the species-richness curve was hump shaped rather than monotonic. Here I investigated elevational gradient of species diversity of birds at Mikura-jima Island, of which vegetation does not sustain much human disturbance. Bird line census during breeding season in 7-10 June 2001 at the island revealed hump shaped curve with the maximum at about 400 m altitude both in observed number of species and in species diversity. This shape of the curve could be mainly explained by the following. There are mainly four types of vegetation along altitude, which are secondary forest, evergreen forest, highland forest and grassland from low to high elevation. Number of bird species favoring each of the vegetation types as their habitat is dependent on the elevation where the vegetation distributes. The secondary forest, evergreen forest, highland forest and grassland, from low to high, are favored by 7, 9, 6 and 2 species of birds, respectively.
国立科学博物館の論文
2002-12-25