1、J.Geogr.Sci.2023,33(3):483-507 DOI:https:/doi.org/10.1007/s11442-023-2093-y 2023 Science Press Springer-Verlag Impacts of climate change and anthropogenic activities on the normalized difference vegetation index of desertified areas in northern China MENG Nan,*WANG Naiang,CHENG Hongyi,LIU Xiao,NIU Z
2、henmin College of Earth and Environmental Sciences,Center for Glacier and Desert Research,Scientific Observing Station for Desert and Glacier,Lanzhou university,Lanzhou 730000,China Abstract:Vegetation plays a key role in maintaining ecosystem stability,promoting biodiver-sity conservation,serving a
3、s windbreaks,and facilitating sand fixation in deserts.Based on the Moderate Resolution Imaging Spectroradiometer Normalized Difference Vegetation Index(MODIS NDVI)and climate data,a TheilSen median trend analysis combined with the MannKendall test and partial correlation and residual analyses were
4、employed to explore spatiotemporal patterns of vegetation dynamics and key drivers in the Badain Jaran and Tengger deserts and Mu Us Sandy Land.Data were collected during the growing season between 2001 and 2020.Further analyses quantified the relative contribution of climate vari-ation and anthropo
5、genic activities to NDVI changes.Results revealed a predominantly in-creasing trend for average NDVI.The spread of average annual NDVI and growth trends of the vegetation were determined to be influenced by spatial differences.The area with im-proved vegetation was greater than that of the degraded
6、region.Climate variability and hu-man activities were driving forces controlling vegetation cover changes,and their effects on vegetation dynamics varied by region.The response of vegetation dynamics was stronger for precipitation than temperature,indicating that precipitation was the main climate v
7、ariable influencing the NDVI changes.The relative role of human activities was responsible for 70%of the changes,demonstrating that human activities were the main driving factor of the NDVI changes.The implementation of ecological engineering is a key driver of increased vegeta-tion coverage and has
8、 improved regional environmental quality.These results enhance our knowledge regarding NDVI change affected by climate variation and human activities and can provide future theoretical guidance for ecological restoration in arid areas.Keywords:desert;sandy land;vegetation dynamics;climate variation;
9、human activities;relative contribution rate 1 Introduction With climate change,regional responses,and regional human-earth coupling,terrestrial Received:2022-05-15 Accepted:2022-09-30 Foundation:National Natural Sciences Foundation of China,No.41871021 Author:Meng Nan(1996),PhD,specialized in climat
10、e change.E-mail:*Corresponding author:Wang Naiang(1962),PhD and Professor,specialized in climatic environment change.E-mail: 484 Journal of Geographical Sciences ecosystems are experiencing considerable change(Forzieri et al.,2017;Piao et al.,2020).As a crucial part of ecosystems worldwide,the funct
11、ions of vegetation are to change the surface conditions,regulate local microclimate,adjust the global carbon balance,and reflect regional human activities(Eastman et al.,2013;Sun et al.,2015;Qu et al.,2020;Wang et al.,2022).Changes in vegetation cover are the direct result of the ecological environm
12、ent.It is common to use an index to evaluate terrestrial and environmental conditions,especially to measure the degree of desertification(Hellden et al.,2008;Wei et al.,2021).Understanding the dynamic processes and spatial patterns associated with vegetation change and their mechanisms is a critical
13、 concern in studies of land ecosystem change(Piao et al.,2015;Du et al.,2019).Satellite remote sensing-based vegetation indices offer the best method for monitoring spatial and temporal vegetation change regionally and globally(Nemani et al.,2003;For-zieri et al.,2017;Song et al.,2018).NDVI is the m
14、ost common index for characterizing vegetation growth,which has a positive correlation with vegetation coverage(Tucker et al.,1985;Eastman et al.,2013;Li et al.,2017).In recent years,researchers have monitored vegetation dynamics to identify the driving factors at regional and global scales.The tren
15、d of vegetation greening plays a key role at the global scale,especially in the mid-latitude of the Northern Hemisphere,owing to global change(Mynel et al.,1997;Eastman et al.,2013;Piao et al.,2020).Vegetation activity has also been increasing in China(Chen et al.,2019).The synergistic effects of cl
16、imate variation,namely temperature and precipitation,and an-thropogenic factors(Sun et al.,2015;Gao et al.,2019;Jin et al.,2020;Piao et al.,2020)influence vegetation dynamics.There are considerable differences in the response charac-teristics of Normalized Difference Vegetation Index(NDVI)under different wet and dry conditions and climate change.In ecological regions with limited temperature,climate warming promotes vegetation coverage in temperature-limited areas but can inhibit vegeta-tion gro