Climate Change Impacts on Vegetation in Humid Asian Mountains

抄録

　Diverse landscapes or ecosystems of mountainous terrain pose a challenge to predicting the response of mountain ecosystems to potential global change impacts. Isolated high mountain areas are intrinsically fragile habitat-islands surrounded by lowland vegetation that is impassable to highland biota. In humid East Asia, the more or less continuous extension of high mountain chains exhibits a latitudinal transition of vertical arrangement of forest zones on mountains. Since Humboldt, differences between vegetation zonation in humid tropical and temperate mountains have been described, but the causal temperature factors responsible for the patterns have not been fully explored. This has made it difficult to evaluate the impact of climatic change on mountain vegetation. In temperate mountains, latitudinal transition of vegetation is controlled by increasing temperature seasonality or minimum winter temperature. In tropical mountains, a year-round decrease in temperature with no seasonality causes a shortage of energy for forest growth as altitude increases. By distinguishing between these two temperature factors, most of the structural diversification in terms of life-forms, biomass, stratification, and diversity, among tropical and temperate mountain-forests can be explained. Furthermore, the critical temperature factors controlling the patterns can be used for elucidating potential global-warming-induced changes in forest zones and the causal effects, particularly at the interface between tropical and temperate vegetation in the mid-latitudes.