Abstract
Papers on alien species and control measures were called for the Journal and a review paper and an original paper are included in this issue. In the review paper, Miyawaki and Washitani describe the present situation of invasive alien plants in riparian habitats of Japan based on the monitoring data obtained by the Ministry of Land, Infrastructure and Transport, and propose an ecosystem approach for the management of the invasive species populations in order to conserve biodiversity in riparian plant communities. The original paper by Tamura et al. deals with distribution patterns of an invasive Formosan squirrel in urban areas and concludes that size of the forest with broad-leaved evergreen trees is an important factor for successful invasion by the squirrel. It indicates that habitat restoration in urban area might result in helping invasion of some alien species. This is a reason why we should investigate on uninvasibility of natural communities to apply the mechanisms to habitat restoration in ecosystem management. In this paper, a model for judging investment ratio of direct community manipulation to habitat manipulation (Community-Habitat Investment Model) was proposed.
