On the connexion of vegetation dynamics with climatic changes in High Asia

Within the scope of research on environmental changes in High Asia indications of desiccation and thermal oscillations are described. They refer to different periods and are caused by different climatic factors. Distribution patterns of forest constituents with disjunctions in the Central and Eastern Himalayas are explained with changes in monsoonal rainfall presumably during the Holocene. thern Tibet the plant relicts of one of the younger Holocene phases of higher humidity (“Kobresia pygmaea age”) have been widely destroyed by the Himalaya-föhn, giving way to semiarid alpine steppe on stone pavements. observations of a recent intensification of gelifluction processes in the southeastern part of the Tibetan Plateau is in accordance with a cooling period between the late 1950s and the late 1970s. viously decreased vigour and lacking regeneration of the climax vegetation in the alpine belt becomes conceivable under the presumption that the respective cover of alpine turf is a relict of the climatic optimum which slowly but increasingly deteriorated since then. ease of plant vigour at climatically sensitive vegetation borders (upper treeline, drought limit of forests, transition zone between alpine Cyperaceae mats and the free gelifluction belt, transition zone between humid alpine mats and alpine steppe) gives evidence of diminishing winter precipitation during the last 30 to 40 years in the Karakorum.