A Systematic Study on the Structure, Process and Evolution of the Ecosystems in Western China Arid Region

摘要

Based on studies of lake sediment, loess sediment and ice amass record and using geographical information system, remote sensing and ecological landscape methodologies, a systematic study on the structure, processes and evolution of the ecosystems in the western China arid region was conducted on time scales of 10,000 years, 1000 years, 100 years, and less than 100 years. Beginning from the Brand-new Life era, the climate of the western China arid region has been changing alternatively between warm-dry and cold-wet periods. The characteristics of climate differ among places and years in the early, middle, late Brand-new Life era. The human population relied mainly on the degree of aridity over the past 280-350 years when the rainfall demonstrated periodical changes and a slight decrease trend. However, in the past half century, the climate of Tianshan Mountain and Xinjiang area showed increases in both air temperature and rainfall. In these areas, vegetative land covers, especially typical grasslands, expanded significantly from 1980s to 1990s. It is also found that within certain climate environments the vegetative land covers in the oases have positive impacts on regional whether by increasing the rainfall of the areas.