東京都区部の屋上緑化地における鳥類の分布特性に関する研究

Abstract

The purpose of this study is to determine the factors influencing bird distribution in rooftop vegetation in an urban area. We surveyed the distribution of bird species using point count method in fourteen study sites in the Tokyo Ward. We examined the relationships between bird distribution and other environmental factors, including vegetation on the rooftops and land use around the study sites. Pearson's correlation coefficient and TWINSPAN were used for data analysis. In this study's result, a significantly high rate of bird species inhabiting urban areas were found in study sites. Avian species diversity increased with the floristic species richness and the tall-tree-covered area of the rooftop vegetation, and the green-covered area around the study sites. Based upon these results, it may be desirable to increase the area covered with plants, including tall trees (h>3m) on the rooftops, to attract woodland bird species. As bird distribution on rooftop areas has implications for other environmental factors, like a surrounding green area, it appears it would be effective to consider rooftop vegetation area and surrounding green spaces together in the planning stage.