Spatiotemporal Variation of NDVI and Its Driving Factors in the Three Rivers Source Region
The Three Rivers Source Region is an important water conservation area in China and a key area for ec-ological and environmental protection,which is located in the hinterland of the Qinghai-Xizang Plateau.However,the ecological environment in this area is extremely fragile,and it is of great significance to carry out the analysis of vegetation change characteristics and their influencing factors for the ecological protection of the Three Rivers Source region.Based on the MODIS NDVI data from 2001 to 2020,combined with the datasets of climate,topog-raphy,vegetation types,soil texture and human activities,this study analyzes the temporal and spatial variation characteristics and driving factors of NDVI in the Three Rivers Source by using trend analysis,M-K trend test and geographic detector model.The study found that between 2001 and 2020,the average NDVI in this area was 0.42,of which the NDVI in the area of the Lancang River was the highest(0.54),followed by the source area of the Yellow River(0.52),and the lowest in the source area of the Yangtze River(0.32).The NDVI of vegetation in the whole region showed a gradual increase trend from northwest to southeast;The rate of change of NDVI in the source area of the Yellow River showed an increasing trend in the north and a slight degradation trend in the south and the center.The vegetation in most places in the source area of the Lancang River showed a degradation trend,and the vegetation condition in the source area of the Yangtze River basically remained unchanged;The magnitude of influence of each factor on NDVI of vegetation in the Three Rivers Source region was air temperature(0.46)＞elevation(0.40)＞precipitation(0.31)＞soil texture(0.29)＞vegetation type(0.13)＞slope(0.11)＞slope aspect(0.02)＞human activities(0.004);The interaction detection results mainly showed two-factor enhancement,fol-lowed by nonlinear enhancement,and to a lesser extent independence.the interaction of precipitation and eleva-tion had the strongest explanatory power for the spatial distribution of NDVI(65％)among all the driver interac-tions.
Three Rivers Source Regionnormalized vegetation indexgeographical detectordriving factors
NETL
NSTL
万方数据
