Temporal and Spatial Pattern Characteristics of Vegetation in Qaidam Basin and Its Response to Climate Change

Abstract

vegetation is a sensitive indicator of climate change. The spatial-temporal dynamic changes of vegetation cover and aboveground biomass and their relationship with climate factors in Qaidam Basin in recent 13 years were studied by using vegetation index. The results are as follows: (1) the total area of vegetation in Qaidam Basin increased from 2002 to 2015, with a growth rate of 644.11km2/a (R2 = 0.4919). In recent 14 years, the change of vegetation area has been increasing → decreasing → increasing → decreasing, among which the vegetation area has been increasing continuously from 2009 to 2012; (2) During the period of 2002-2015, the vegetation area of each level of vegetation coverage showed an increasing trend, and the increasing rates were 300.2km2/a, 242.8km2/a and 101.2km2/a, respectively, which indicated that the vegetation ecology in Qaidam Basin was developing to a benign trend; (3) the aboveground biomass of vegetation was mainly low-yield vegetation less than 1500kg/hm2, followed by vegetation of 1500-3000kg/hm2, accounting for the total area of vegetation The proportion is less than 10%, and the vegetation area of other grades is very small, only scattered, while the high-yield vegetation larger than 6000kg/hm2 is distributed in the southeast of the basin and the alpine mountains around the basin; (4) there is a certain coupling relationship between the climate and vegetation change in Qaidam basin, which is reflected in the positive correlation between the total vegetation area and the annual precipitation, the precipitation from May to September and the precipitation in summer, and the correlation significance of summer precipitation > may September precipitation>annual precipitation. However, it was negatively correlated with winter precipitation, but not with autumn precipitation and annual average temperature (P > 0.5).