2. Material and methods
Studied site
The studied site is located in Nyingchi City, Tibet Autonomous Region,
China (E94°45’25”, N29°58’10”), which has a warm and semi-humid plateau
climate with annual precipitation and temperature of 650 mm and 8.7℃,
respectively. This region belongs to the upper reaches of the Yarlung
Zangbo River high mountain gorge area, and the average elevation is 2940
m. The typical soil types are mountain brown soil, -yellow-brown soil
and sandy loam deposited in river flats, which are generally in coarse
textures and possess various gravel contents (Gao et al.,2021). The main
native herbage plants include Kobresia myosuroides , Stipa
capillata , Carex hirta, Potentilla chinensis, Elymus dahuricus .