58.帰化植物セイタカアワダチソウおよびその近縁種の分布構造

概要

論文の詳細を見る
The North American wild flower goldenrod, Solidago altissima, was probably introduced into the northern area of Kyushu, a southern island of Japan, in 1952, 30 years ago. Since this invasion, the plant has rapidly been distributed throughout all the southern Japanese islands. The related species, Solidago gigantea, was also introduced from North America within the past few decades into Hokkaido, the northern most Japanese island. This survey was carried on to check the distributions and population structures of S. altissima and S. gigantea in all the Japanese islands through travel and field observations in 3 recent years. The results of the examinations are as follows: (1) At the present time S. altissima grows most density in the northern Kyushu area and the Hanshin area (Osaka and Kobe) (Photo. 1-3, Fig. 1 grade 5, Fig. 2). (2) The Chugoku area, which connects the northern Kyushu and Hanshin areas, shows a second-grade distribution and population density of S. altissima. The southern Kyushu and Nagoya areas have the same grade of distribution (Fig. 1 grade 4, Fig. 2). (3) It is interesting that the Solidago plants are not found in the Tohoku area of northern Japan or in the Hiroshima region of the Chugoku area (Fig. 2). (4) In the Kanto area (including Tokyo) and on Shikoku island S. altissima grows with a medium-grade distribution (Fig. 1 grade 3, Fig. 2), but it seems now to be spreading. (5) S. gigantea is mainly found in Hokkaido (Fig. 2). The highest grade (Fig. 1 grade 4) of the distribution of the species is to be found in the Sapporo-Iwamizawa area of central Hokkaido. The species has spreaded recently to the Kushiro and Abashiri regions of eastern Hokkaido (Fig. 2). (6) In general, the distribution of Solidago plants is poor in areas along the Sea of Japan. On the basis of the above distributions of S. altissima and S. gigantea, it is considered that the follwing factors account for the rapid distribution of the plant: 1. The areas in the Japanese islands where the Solidago plants are to be found have climatic conditions similar to those of the plants native area in North America (Fig. 3, Table 1). It seems that the adaptive mechanism of the plant to the environment work in both the native and Japanese areas. Especially the northern Kyushu and Hanshin areas, in which the density is greatest, have conditions of annual temperature and moisture quite similar to those of the southeastern United States, the homeground of goldenrods (The State Flower of Alabama is the goldenrod). 2. Solidago plants have an excellent reproductive system in those of pollen dispersion, seed dispersion, and the development of the root system. The system of seed dispersion is especially well developed, working chiefly by means of wind and human transportation system (Plate 15, 16). 3. Solidago plants are now a well-developed evolutionary period in terms of adaptability and variability by means of hybridization. It seems that these adaptabilites and variabilities encourage the invasion in new area of habitation. 4. It is considered that, in various ways, man might have helped to produce the rapid development distribution of Solidago plants in the Japanese islands from North America. The following ways are possible: (a) Railway transportation seems to encourage the seed dispersion of the introduced Solidago plants because the distribution of the plant has developed along the railway (Fig. 2, Plate 18). (b) Landdevelopment and the construction of new houses has also given a chance for the invasion of Solidago (Plate 19). The Solidago species does not invade places where a native plant grows well. (c) Cuttings of the stems by hand do not exterminate the plant, but increase its variability by gene exchange through pollen dispersions in different flowering periods.
東京女子大学の論文
1982-03-20

著者

福田一郎
東京女子大学

58.帰化植物セイタカアワダチソウおよびその近縁種の分布構造

スポンサーリンク

概要

著者

関連論文

スポンサーリンク