The effects of development on forest-patch characteristics and bird diversity in Suji,South Korea

In a forested area located in the Suji District of Yongin City, Gyunggi Province, South Korea, the relationship between development and forest-patch characteristics and that between development and bird biodiversity were observed and analyzed. As four development projects progressed over a 13-year period (1990–2003), Landsat images showed how a continuous forest was reduced and fragmented and how isolated forests either shrank or disappeared. The ratio of the edge area to the forested area changed also and reflected the stages of the four development projects. A single continuous forest patch was studied, and it showed fragmentation and a reduction in size over time associated with the development projects. The effect of the later developments on adjacent forested areas was much greater than the effect of the initial development. As expected, the initial development affected the forested area near the initial development, but the later developments also significantly affected the same area near the initial development. Bird population characteristics—numbers of individuals and species (biodiversity)—were analyzed using field observations at nine sites in both continuous and isolated forest areas. A gradient of decreasing bird species and the number of individuals was established by an analysis of observations made in the interior, intermediate, and edge areas of the continuous forest. Whereas both the isolated forest and the interior areas of the continuous forest studied had similar numbers of individual birds, the isolated forest areas and the edge areas of the continuous forest showed significantly lower biodiversity than the interior areas studied. The results show that developments cause not only the forest loss, fragmentation, and expansion of the edge area but also a lowering of bird diversity; especially, the later developments have been under more pressure to develop the surrounding area. Therefore, it is necessary to manage the edge area, which is vulnerable to development, to minimize the effects of development.