The Tian Shan plays a key role in the sustainable development of ecological environment in arid and semi-arid regions along the Silk Road Economic Belt as an important ecological barrier connecting the Central Asia and Xinjiang, China. Previous studies indicated that the global warming led to a series of ecological problems in Tian Shan, such as a decrease in snowfall rate, severe glacier melting, and significant grassland degradation. It has become an important and urgent task to monitor the dynamic changes of vegetation in the region and analyze its driving factors. Based on MODIS NDVI data, we calculated the Fractional Vegetation Coverage (FVC) of the Tian Shan from 2000 to 2016 using the harmonic analysis of time series (HANTS) algorithm and the dimidiate pixel model. The linear regression and partial correlation analysis were used to map the tempo-spatial variations of FVC and to analyze the correlation results with the precipitation and temperature. The major conclusions were drawn as follows: (1) The vegetation growth in Tian Shan had significant regional differentiation, the mean FVC in the northern, central and southern part of Tian Shan was 0.37, 0.49 and 0.26, respectively. In addition, the FVC value was 0.29 in the eastern Tian Shan, which is inside China, and 0.43 in the western Tian Shan, which is outside China. The FVC was higher on northern slope and western part. (2) There were 66.8% of the vegetation pixels displayed in an improving trend. The farmland and forest with the highest FVC showed degradation trend with the area proportions of 66% and 53%, respectively. However, the shrub-desert and shrubland with the lowest FVC showed improving trend with the area proportions of 88% and 74%, respectively. Moreover, the most widely distributed grassland has an improvement ratio of 64%. (3) The temperature and precipitation of Tian Shan were increased by 0.85 °C and 1.87 mm respectively during the time period from 2000 to 2016, which indicated equivalently an increment of 6.2% of the average temperature and an increment of 1.4% of the precipitation, respectively. (4) The correlation ratios of temperature and precipitation with the FVC were 18.0% and 42.6% respectively. The precipitation was the dominant factor affecting the change of vegetation in Tian Shan. (5) The vegetation in the typical regions like Bayinbuluke Grassland was greatly disturbed by overgrazing. We suggested that the ecological restoration in the vegetation degeneration area should be strengthened and the regional governments should make the reasonable plan for the sustainable tourism development.
Chen Xiu-yan, Fu Bi-hong, Shi Pi-long, Guo Qiang
. Vegetation dynamics in response to climate change in Tian Shan, Central Asia from 2000 to 2016[J]. Arid Land Geography, 2019
, 42(1)
: 162
-171
.
DOI: 10.12118/j.issn.1000-6060.2019.01.19
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