A numerical niche differenciation model, previously proposed by the authors, was applied to reproduction of meshed vegetation maps of three alternate bars formed in a row at a downstream reach of the Yoshino River, in Shikoku island, Japan. The model was utilized for judging the dominant plant community type in each mesh element from a set of physical habitat attributes and so-called preference curves. In cases when the preference curves were prepared with regard to an individual bar and referred to within this bar alone, the dominant plant communities were successfully judged with an accuracy of 70%. In cases when a set of preference curves were commonly applied to the three bars, however, accuracy was considerably reduced.