Evaluation of Habitat Functions of Fragmented Urban Forests for Wildlife: The Case of Kitakyushu City

Urban forests with various shapes and areas exist in the mid-northern part of Kitakyushu City, Japan. These forests, which are dominated by evergreen canopy species, became fragmented largely in the 1960s. The differences in species composition between sample plots, as well as within the plots, were large for recently recruited small individuals in comparison with large ones. Thus, the effects of fragmentation on recruitment of woody species have recently become stronger. A molecular ecological approach also indicated that the effects of fragmentation on the genetic structure of one of the dominant woody species Neolitsea sericea had become severe. The effects of fragmentation on forest habitat functions were significant for large mammals such as wild boars as well as small mammals such as mice. For mid-sized mammals, however, the effects varied between species. Thus, to evaluate the habitat function of urban forests for wildlife, it is important to analyze the effects of fragmentation on various taxa using hierarchically related levels of biological organization.