Study On Spatial-temporal Evolution Of Vegetation Ecology And Its Influencing Factors In Subei Lake Basin

The Ordos Basin is rich in coal,oil,natural gas and other mineral resources.It is a state-level energy and chemical base.The basin is located in the arid-semi-arid region of northwestern China.Water resources are scarce and the ecological environment is relatively fragile.The construction of the ecological environment is very important for the construction and development of the Ordos energy base.And vegetation is an important component of terrestrial ecosystems and plays a very important role in maintaining the energy balance in terrestrial ecosystems.In particular,for arid and semi-arid areas,vegetation is an important indicator of whether ecosystems are good or not.Subei lake basin locates in the northern of the Ordos plateau basin,it is one of the important construction areas of the Ordos energy base.In 2006,Subei lake basin was used as water supply source to supply water to the Shenhua coal liquefaction project,resulting in the occurrence of vegetation such as salix matsudana in some areas.This shows that there is a certain contradiction between the construction of the energy base and the development of water resources and vegetation ecological environment in Subei lake basin.Therefore,this paper relies on the “1:50 000 hydrogeological survey of lakes concentrated in northern Ordos Basin” project,with Subei lake basin as the main research area,based on the collection and analysis of existing data,guided by hydrogeology and ecology theory,comprehensively using field surveys,remote sensing interpretations,GIS technology and statistical analysis methods to study and analyze the temporal and spatial distribution of vegetation and its response relationship with temperature,precipitation,and groundwater during the period from 2000 to 2015 in Subei lake basin.This article mainly obtains the following several understanding.First,use remote sensing method to estimate NDVI and vegetation NPP.The results show that the vegetation in Subei lake basin is a slow and fluctuating growth trend over the interannual period,and there are an obvious differences in the spatial distribution of vegetation types.Second,using statistical methods to analyze the response relationship between vegetation and depth to water table.The results show that NDVI increases first and then decreases with the increase of depth to water table,and the surface vegetation types are abundant within 4 meters of depth to water table.Third,using one-dimensional linear regression to analyze the response of vegetation and meteorological factors.The results show that the impact of temperature on vegetation is greater than the effect of precipitation.In the range of 20°C to 21°C,vegetation and air temperature are positively correlated,when temperatures above 21°C,it will have a negative effect on vegetation growth.The correlation between vegetation and precipitation is weak,and there are an obvious lag effect and cumulative effect.This paper studies the temporal and spatial evolution of vegetation and its relationship with environmental factors in order to provide certain data technology support for the development of ecological environment and groundwater resources in arid and semi-arid regions.