Assessing the Spatiotemporal Evolution of Anthropogenic Impacts on Remotely Sensed Vegetation Dynamics in Xinjiang, China

Abstract

The dynamics of the ecosystem represented by vegetation under the influence of human activities have become an important issue in the study of the regional ecological environment. Xinjiang is one of the most ecologically fragile areas in the world, and vegetation changes have received extensive attention. Xinjiang is one of the most ecologically fragile areas in the world, and vegetation changes have received extensive attention. However, the spatiotemporal patterns and evolutionary trends of anthropogenic impacts on vegetation dynamics in Xinjiang are still unclear. In this study, the anthropogenic impacts on vegetation dynamics were quantitatively assessed by combining the improved normalized difference vegetation index (NDVI) prediction model and the residual analysis method in Xinjiang, China. The human driving factors were analyzed with the support of a stepwise multiple regression model for vegetation changes at the county scale. Based on trend analysis and the Hurst exponent, the spatiotemporal characteristics and evolutionary trends of the impact of human activities on vegetation change were discussed. The results show that (1) the NDVI values in Xinjiang showed a gradually increasing trend at a rate of 0.005/10 years from 1982 to 2018, and the vegetation dynamics mainly showed significant improvements (57.09% of the vegetated areas), especially for crops. (2) The anthropogenic effects of vegetation changes in Xinjiang mainly included positive impact increases (43.22% of the vegetated areas) from 2000 to 2018. Human activities promoted the increase in the NDVI of various vegetation types. Both the positive and negative impacts of human activities increased over the study period, and the growth rate of the positive influence (0.08%/10 years) was higher than that of the negative influence (0.04%/10 years). (3) The cultivated area, GDP of primary industry, and population are the main anthropogenic factors causing the increase in NDVI, which dominate the vegetation greening in 30.34%, 29.22%, and 28.09% of the counties in Xinjiang, respectively. The animal husbandry population, agricultural population, and livestock number are the main anthropogenic factors causing the decrease in NDVI, which dominate the vegetation degradation in 23.60%, 21.35%, and 17.98% of the counties in Xinjiang, respectively. (4) The evolutionary trend of the anthropogenic impact on vegetation dynamics in Xinjiang will be dominated by anti-persistence (53.84% of the vegetated areas), thereby mainly showing that the positive impacts continued to increase (22.56% of the vegetated areas), especially for crops, shrubs, grasslands, and alpine vegetation. Our results are helpful in understanding the characteristics and evolutionary trends of vegetation changes in arid areas caused by human activities and are of significance as a reference for policymakers to appropriately adjust policy guidance in a timely manner to promote the protection and sustainable development of fragile ecosystems.

Assessment of ecological quality in Northwest China (2000–2020) using the Google Earth Engine platform: Climate factors and land use/land cover contribute to ecological quality

“…The improved areas were not only in the oases, but also in the desert-oasis ecotone and deserts. The main reason for this change is that the climate in Xinjiang has become warmer and more humid; the increased precipitation has greatly improved the soil moisture content and habitats, leading to the recovery of vegetation (Guan et al, 2021). Warmer temperatures have also accelerated the melting of glaciers and glacial snowmelt is the main means of water recharge in arid areas.…”

“…For instance, the Three-North Shelterbelt Program (Li et al, 2012;Zhang et al, 2016;Guo et al, 2022a) and the comprehensive management project in the Tarim River Basin (Xue et al, 2019) serve as good examples in China. In the last four decades, vegetation in Xinjiang has recovered, regional desertification has been improved and human activities have had a positive effect on the greening of the region's vegetation (Guan et al, 2021). Soils have been improved in some areas with native soil salinity due to the improvements in vegetation (Ge et al, 2022b).…”

“…Evaporation exceeds precipitation and therefore groundwater and the seasonal melting of glaciers serve as the primary sources of freshwater recharge, although they are lost to evapotranspiration (Rodell et al, 2018). The vegetation is sparse and consists mainly of farmland and grassland, although the overall trend is toward greening for all vegetation types, particularly farmland (Ge et al, 2021;Guan et al, 2021). The main cultivated crop is cotton, of which Xinjiang is the largest producer in China.…”

Spatiotemporal Evolution and Driving Forces of Vegetation Cover in the Urumqi River Basin

“…The average strength of the explanatory power of natural factors on vegetation cover over the 21-year study period varied with temperature (0.216) > elevation (0.205) > soil clay content (0.172) > precipitation (0.163) > soil sand content (0.138) > slope (0.059) > slope orientation (0.014) ( Figure 6 ). Changes in vegetation cover are complex processes and are significantly influenced by human activities (land use type, GDP density, population density and distance from roads) [ 23 , 54 , 55 ]. Previous studies in Xinjiang have shown that human activities and active policies are the main influences on the regional vegetation cover [ 56 ].…”

Anthropogenic Transformations of Vegetation in the Kuyalnik Estuary Valley (Ukraine, Odesa District)

“…Several scientists [3][4][5][6][7] developed successive changes in vegetation cover, and clarified the challenges to sustainability and risks of biosystem losses [8][9][10]. The anthropogenic aspect of evolution (resistance and synanthropization) has been developed [11][12][13][14][15][16]. Synanthropization of vegetation refers to the process of replacing species of natural communities with synanthropic species that are resistant to anthropogenic impact.…”