The factors affecting land birds in urban parks of Osaka
Hiroshi HASHIMOTO, Yosihiro NATUHARA and Yukihiro MORIMOTO
Abstract: Bird survey was conducted in 85 urban parks in the breeding season of 2000 in
Osaka city, western Japan, to clarify the factors affecting bird species richness and bird
community in urban small parks. Eleven species of land birds were observed. As the result of
comparison of goodness of fit between a species-log area and a species-log tree area curve,
the former fitted better. We made a multiple regression analysis to predict the number of
species in the urban parks. Tree area of parks was a positive factor, whereas areas of streets,
offices and commercial buildings were negative factors affecting species richness.
But the obtained model fit less than that of an earlier study in Osaka Prefecture.
The reason may be related to the small number of bird species in urban parks in the
central area of Osaka city. Bird communities were classified using TWINSPAN.
We recognized three types of bird species groups, such as, "urban birds", open habitat
species and forest species. The result of a discriminant analysis showed that tree area
positively affected bird communities in urban parks. Street coverage, and office and
commercial building coverage had negative effects. Busy streets and tall buildings will
interfere bird movement. We suggest the minimum area of tree stands required for creating
adequate habitat for forest birds in an urban area may be about 5 ha.
Key Words: bird community, multivariate statistics, Osaka, species-area relationship, urban parks
H. Hashimoto, Y. Natuhara and Y. Morimoto (2003) The factors affecting land birds in urban parks of Osaka. Bulletin of the International Association for Landscape Ecology - Japan 8: 53-62(in Japanese with English abstract)