Quantitative evaluation of the ecological service function on the Qinghai-Tibet plateau based on GIS analysis

Ecosystem services are essential for ensuring our survival and development and comimg true regional sustainability. Based on the quantitative indicator assessment method of net primary productivity (NPP) of vegetation and GIS spatial analysis method, the spatial distribution characteristics and importance of the functions of water soil retention, soil and water conservation, wind and sand control, and biodiversity maintenance in the Tibetan Plateau were evaluated during 2000-2015. The results show that: (1) The indices of water conservation, soil conservation, wind protection and sand fixation, and biodiversity maintenance functions are high in the southeast and low in the northwest, showing a reducing trend from the southeast to the northwest. (2) From the grading characteristics of the significance of the ecological service features mentioned above, the four types of ecological system services have the largest area, accounting for 27.06%, 19.73%, 61.44% and 41.7% of the gross area of the plateau, respectively; the area of ecological services with weaker functions is the smallest, accounting for 16.47%, 16.96%, 0.97% and 4.06% of the gross area of the plateau, severally. (3) The ecological function of the Qinghai-Tibet Plateau from 2000 to 2015 shows two obvious characteristics, namely, the southern part of the plateau, the Sanjiangyuan region, the southern end of Qinghai Lake and Qilian Mountain area have a decreasing trend of comprehensive ecological service function, the northern Tibetan Plateau, the southern valley of Tibet, the Hengduanshan area have an increasing trend of comprehensive ecological service function, and the rest of the area stays unchanged.