Effects of Climate Change on Land Cover Change and Vegetation Dynamics in Xinjiang, China

Abstract

<jats:p>Since the Silk-road Economic belt initiatives were proposed, Xinjiang has provided a vital strategic link between China and Central Asia and even Eurasia. However, owing to the weak and vulnerable ecosystem in this arid region, even a slight climate change would probably disrupt vegetation dynamics and land cover change. Thus, there is an urgent need to determine the Normalized Difference Vegetation Index (NDVI) and Land-use/Land-cover (LULC) responses to climate change. Here, the extreme-point symmetric mode decomposition (ESMD) method and linear regression method (LRM) were applied to recognize the variation trends of the NDVI, temperature, and precipitation between the growing season and other seasons. Combining the transfer matrix of LULC, the Pearson correlation analysis was utilized to reveal the response of NDVI to climate change and climate extremes. The results showed that: (1) Extreme temperature showed greater variation than extreme precipitation. Both the ESMD and the LRM exhibited an increased volatility trend for the NDVI, with the significant improvement regions mainly located in the margin of basins. (2) Since climate change had a warming trend, the permanent snow has been reduced by 20,436 km2. The NDVI has a higher correlation to precipitation than temperature. Furthermore, the humid trend could provide more suitable conditions for vegetation growth, but the warm trend might prevent vegetation growth. Spatially, the response of the NDVI in North Xinjiang (NXC) was more sensitive to precipitation than that in South Xinjiang (SXC). Seasonally, the NDVI has a greater correlation to precipitation in spring and summer, but the opposite occurs in autumn. (3) The response of the NDVI to extreme precipitation was stronger than the response to extreme temperature. The reduction in diurnal temperature variation was beneficial to vegetation growth. Therefore, continuous concentrated precipitation and higher night-time-temperatures could enhance vegetation growth in Xinjiang. This study could enrich the understanding of the response of land cover change and vegetation dynamics to climate extremes and provide scientific support for eco-environment sustainable management in the arid regions.</jats:p>

Spatial-temporal Evolution of ESV in the Yellow River Basin and Its Response to Land Use Change

“…Because the economy in the upstream areas such as Qinghai, Lanzhou and Sichuan is lagging behind that of the downstream areas, there is less construction land, grasslands are widely distributed, and these areas have higher altitudes and lower accessibility to human activities. The water source produced by melts snow and ice all year round nourishes the local grassland [32], and mainly undertakes ecological service functions such as soil and water conservation [33]. The northern Qilian Mountains, Taihang Mountains and Qinling Mountains are rich in grassland forest resources.…”

China’s deserts greening and response to climate variability and human activities

“…In the Hexi region, approximately 70% of the vegetation area presented a significant increasing trend, and only 2.85% presented a significant decreasing trend [ 74 , 75 ]. And a significant increasing trend of the NDVI was observed in Xinjiang [ 76 ]. In general, precipitation has been shown to be the main cause of NDVI rise in arid and semiarid regions, such as the Hexi region, Xinjiang, and Central Asia [ 34 , 73 , 75 , 76 ].…”

“…And a significant increasing trend of the NDVI was observed in Xinjiang [ 76 ]. In general, precipitation has been shown to be the main cause of NDVI rise in arid and semiarid regions, such as the Hexi region, Xinjiang, and Central Asia [ 34 , 73 , 75 , 76 ]. However, from this study, although the correlation between precipitation and NDVI was significant on the annual scale, the area with significant correlation was only 15.14%.…”

Downscaling Snow Depth Mapping by Fusion of Microwave and Optical Remote-Sensing Data Based on Deep Learning

“…The total land area is 0.97 million km 2 , accounting for nearly 10% of China's land area. Junggar Basin is lying between Tianshan Mountains and Altai Mountains, forming a mountain-basin system, which is the most significant landform in NX [46][47][48]. Xinjiang is far from the ocean and has a continental arid and semi-arid climate with an annual mean temperature varying from 4 to 8 • C in NX.…”