Status of hydrophyte communities in the watershed of Yongsan River, southwestern Korea

Abstract

The authors listed hydrophyte communities and surveyed their distributions along the Yongsan River and its tributaries, southwestern Korea, between March 1996 and October 1999 by using phytosociological methods. In total 23 hydrophyte communities were found: they were grouped into 4 submerged hydrophytes, 5 floating leaved hydrophytes, 10 emergent hydrophytes, 3 free-floating hydrophytes, and the Salix gracilistyla community. Surveys of seven river-crossing profiles showed that those hydrophyte communities, the Salix gracilistyla community, and three man-made habitats were regularly distributed from the upper stream to the estuary of the main river and from the stream to the banks depending on the water depth, water flow speed, stream width, and land development along the river. In the flood plain between banks of the middle and lower river, crop lands, sports parks, car parks, cycling roads, dams, reservoirs, and sewage drains have occupied, destroyed, and badly affected habitats of the native hydrophyte communities. Thirteen hydrophyte and other communities were surveyed in the 15 tributary rivers of Yongsan River. Among those communities, three hydrophyte communities, Zizania latifolia, Paspalum distichum, and Potamogeton crispus communities, were commonly found predominating in 11 or 12 of the 15 tributary rivers, and the others were found in fewer than five tributaries, seemingly dependent on the extent of land development.