外来植物オオキンケイギク Ｃｏｒｅｏｐｓｉｓ ｌａｎｃｅｏｌａｔａ の定着した半自然草地の種組成および群落構造と遷移状況

Abstract

For the purpose of making clear of ecological community characteristics and considering with vegetation management methods, alien plant species Coreopsis lanceolata established semi-natural grassland communities were surveyed with vegetation and environmental conditions in the southern part of Nagano Prefecture. These vegetation data were analyzed mainly from the point of view of species composition, community structure, and diagnosis of plant succession. Three types of plant communities (Zoysia japonica dominant type (Zj type), C. lanceolata dominant type (Cl type), Miscanthus sinensis dominant type (Ms type)) were distinguished at the second level of TWINSPAN classification, and eight types of species groups were distinguished. There were differences in life-form spectrum and growth-form spectrum of each community type, with the result that relative photon densities in the communities declined by increasing the shoots densities of C. lanceolata on close to ground. Therefore, native grassland species that have inhabited on the short-grass type grasslands would have declined owing to dominance of C.lanceolata. On the index of degree of succession, Zj type was lower than other types that were almost same degree. These results suggested that by the invasion and dominance of C. lanceolata, species composition and community structure on the semi-natural grassland have altered, and plagiosere succession have been caused.