关键词: 陕西省, 植被覆盖度, 气象因子, 地形因子, 人类活动

Abstract: The aim of this study is to evaluate the changes of vegetation coverage in different landform types in Shaanxi Province since the implementation of ecological projects such as returning farmland to forest or grass. The vegetation coverage of Shaanxi Province was estimated by using the pixel binary model based on the MODIS data from 2000 to 2017. According to the geomorphic division, the spatial and temporal variation of vegetation coverage and its influencing factors were analyzed. Results showed that: 1) Over the past 18 years, the vegetation coverage in Shaanxi Province had an overall increasing trend. The coverage was lower in the wind and sand transition zone and the loess Plateau yet presenting a significant upward trend, while high and stable in the Qinling mountains, Hanjiang Basin and Daba Mountains. The coverage had a downward trend in the Guanzhong Plain. 2) Vegetation coverage in 38.88% of the province boosted significantly, mainly in the Loess Plateau, whereas decreased significantly in 8.49% of the province, mainly around the cities in the Guanzhong Plain and other landform types. 3) The effects of precipitation and temperature on vegetation coverage vary in different landform types. Vegetation coverage in the Loess Plateau was mainly positively and negatively correlated with precipitation and temperature, respectively, while negatively correlated in high altitude areas of Qinling-Daba Mountains. 4) The vegetation coverage was lower in the area with elevation less than 500 m and slope less than 8°, and the vegetation coverage was higher in the area with elevation above 1 500 m and slope above 15°. The research results will offer scientific basis for partition implementation of ecological and environmental protection in Shaanxi Province.

Key words: Shaanxi Province, vegetation coverage, meteorological factors, topographic factors, human activities