抄録
Two hundred and six stands of submerged macrophytes were surveyed in Lake Biwa by SCUBA diving. Among the 20 species recorded throughout the survey, Hydrilla verticillata, Potamogeton maackianus and Elodea nuttallii were most-abundant species. Applying priucipal component analysis, all the species could be reasonably ordinated by the first (PC1) and second (PC2) principal components. Considering the horizontal and vertical distribution of respective species, PC1 and PC2 were respectively interpreted to represent hypothetical species able to grow in a windless habitat or to have a tolerance for wave force. Results suggested wind force to be the most important factor influencing the distribution of submerged macrophytes in Lake Biwa. Changes of submerged macrophyte flora, due to either water quality degradation or invasion of exotic species in the lake in recent years, are also described.
