Phytosociological studies in the north-eastern Tibetan Plateau (NW China) A first contribution to the subalpine scrub and alpine meadow vegetation
Kürschner, Harald; Herzschuh, Ulrike; Wagner, Dorothea
published: Dec 14, 2005
The study contributes to the knowledge of the high mountain vegetation of the north-eastern Tibetan Plateau. The most common and most impressive vegetation units in the area are Potentilla scrub, alpine grassland and alpine Kobresia mats, the latter forming the zonal vegetation under the cold and moist climatic conditions. Phytosociologically, the Kobresia mats can be classified into the new and widespread Leontopodio souliei-Kobresietum humilis, essential as a grazing resource for domestic livestock in summer. In relation to temperature, soil conditions, water availibility and grazing pressure, four developments [Juncus thomsonii-development (on permafrost soils), Kobresia capillifolia-development (under high grazing pressure), K. schoenoides-development (on moist to swampy soils), typical development] can be observed. The alpine grassland, dominated by medium-sized Poaceae rather than by Cyperaceae, belongs to the new Moringo chinensis-Elymetum nutantis, which is widespread especially in the Qilian Shan. It is frequently used for winter pasture. The Kobresia royleana-Potentilla parviflora community at present summarizes the 'Potentilla scrub' of the area. Its syntaxonomical classification, however, remains open owing to the taxonomical difficulties of the 'Potentilla fruticosa'-aggregate and the absence of sufficient samples. The species diversity, structure, site ecology and effects of human influence are elucidated for all three vegetation units. Altogether, they display a relatively high number of Sino-Himalayan floral elements indicating a common higher-ranked syntaxon, still to be described, when more samples are available from the large Tibetan Plateau.