Systematic studies of Gramineae and Cyperaceae in Himalayas.

点击翻译按钮获取中文摘要

We will report here the systematic and ecological studies of the flora of the Gosain Kund area in Langtang Himal, central Nepal.1.Systematic studyIn this research, we collected about 3000 herbarium specimens of Gramineae and Cyperaceae.We identified 55 species of 29 genera in Gramineae and 35 species of seven genera in Cyperaceae.Colpodium tibeticum, Festuca cumminsii and Paspalum dilatatum are the first record in the alpine region of central Nepal.Chromosome numbers of 25 species of Carex, Kobresia and Cyperus were found for the first time in this study.Consecutive chromosome numbers, 2n=50-120, were found in Koresia, showed many cytological races of Kobresia were distributed in alpine region of Himalaya.2.Relationship between gramineous plants and topographical gradientA belt transect was set on one of the scree slope near Gosain Kund.The dominant species on the belt was Kobresia nepalense.The second dominant species was Potentilla contigua, and the third dominant was K.pygmaea.Cyper … More aceae and Gramineae species tend to appear on the middle and upper part of the scree slope which is relatively stable.In the lower part of the slope, which is unstable by rocks from the upper part of the slope, P.pygmaea was dominant.The mean number of the species in the plot was greater in K.nepalense and K.pygmaea dominant area.3.Assessment of grazing effects on grammineous plantsThe Arundinella community was dominant at the upper limit of the forest zone, while the Poa and Festuca communities were dominant above 4000m.Between these zones, the Kobresia communities were dominant, which is characteristic to the alpine Himalaya.These communities were heavily used by domestic ungulates such as sheep, goats, horses and cattle.Plants growing in both the Kobresia and Potentilla communities varied in sizes according to the difference of grazing intensity.It was shown that the Kobresia communities are unique in the alpine Himaraya and that grazing seems to be a key factor for their dominance and miaintenance. Less