Environment Evolvement And Spatio-Temporal Patterns In The Source Regions Of Yangtze, Yellow And Lancang Rivers

Yangtze and Yellow Rivers are regard as the mother rivers of China. So the recent enrionmental degradation of source regions of Yangtze, Yellow and Lancang Rivers get more attention from government and research field who put more devotion to improve it. The research of its environment evolvement is the basic premise of its environmental status and quality asseeement as well as equal protection.Based on the summings-up of the theory of environment evolvement, by way of 3 years'fieldwork (2002～2004), literature search, tree's growth ring analysis, meteorologic remote data analysis and meteorologic observation data analysis, the environment evolvement in geological time, the environment changes recently, environmental status, spatio-temporal patterns of ecosystems, determinant ecosystem of research area are researched and discussed. The results are as following:As the part of Qinghai-Tibetan Plateau and its transitional zone between north fauna and south fauna, environment evolvement and spatio-temporal patterns of ecosystems of research area is the outcome of globe climate changes and upheaval of Qinghai-Tibetan Plateau. It was shallow sea with some islands that developed tropical rain forest during Devonian and Triassic. It was becoming land during Jurassic and Cretaceous. It was sub-tropical climate in Tertiary. It was dry in early Eocene, warm and wet in middle Eocene. Then it became dry again in late Eocene and early Oligocene because of Plateau's early upheaving (500 m). It went into warm and wet in middle and late Oligocene. It became dry and cool again due to upheaving (500～1 000 m) and globe climate colding. There were forest (Nangqian), shrub steppe (Maduo), desert steppe from southeast to northwest during Eocene and Oligocene. Immemorial lakes was developed in Nangqian and area around modern Qinghai-Tibetan road. From early Miocene to middle Pliocene, it was quite warm and humid under the influence of Mediterranean climate and Indian Ocean monsoon climate, thus sub-tropical forest and forest steppe distributed far and wide, and immemorial lakes expanded to Zhiduo, Dari, Gande, Guide, Tongren and Zeku. From late Pliocene to the very early-Pleistocene in Quaternary, Plateau upheaved mightily (from 1 000 m to 2 000 m), glacier appeared, it reverted to warm and wet after short time of cold and dry. Vegetation succession emerged with the climate...