1. The analytical studies were made to clarify the community structure after drainage, especially of the amphiphyte zone on the littoral areas. Three typical types of vegetation are recognized in about thirty artificial reservoirs, in Fukui, Shiga and Hiroshima Prefectures in Japan, whose basins are dried up in summer.
2. The first vegetation type indicates the regular zonal arrangement, and is characterized by the amphiphyte zone which is predominated by the annual plant communities. The second type exhibits the typical vegetation type, which is the intermediate structure between the first and the third, as usually found in many never-dried up pond vegetations, and its amphiphyte zone is occupied by the communities of both of the large- and the small-stemmed emergent plants. The third type shows the marshy vegetation, and it is most remarkable that its amphiphyte zone which is occupied by the communities of the large-stemmed emergent plants, especially by
Phragmites, spread out over the central areas.
3. According to the analytical studies of life-form spectrum, Hemicryptophytes generally seem to be abundant in the basins of all three types. Besides, the amphiphte zone of the first type indicates therophytic, of the second shows hydrophytic and of the third is helophytic type.
4. The components of Therophytes in each dominant community remarkably increase in the amphyiphyte zone of the first vegetation type, though they decrease in those of the second type. On the contrary, the helophytic components are moderately poor in the amphiphyte zone of the first type though they are considerably abundant in the second and the third vegetation types.
5. The hydrarch which succeeded from the first to the second and ended in the third type will be illustrated in the vegetation among the three types of the artificial reservoirs.
6. The preservation of seeds of the annuals under the edaphic condition in winter, interspecific correlation between the germination ability of annuals, and the biotic control of Helophyes to annuals will be effective for the development of early stage of the community after drainage in the artificial reservoirs.
抄録全体を表示