2.1. Study area and experimental design
This study was conducted in Ganchaitan, close to Haibei station
(101°19′E, 37°37′N, 3100 m), and included two neighboring sites (i.e.,
shrubs and grassland) in the northeastern Qinghai-Tibet Plateau, located
in Qinghai Province, China, (Figure 1). The region is in a semiarid,
cold, high-altitude climate zone(Dai et al., 2019b). The mean annual
precipitation is approximately 562 mm. Almost 80% of the annual
precipitation falls during the growing season (i.e., from May to
September). The mean annual air temperature is approximately -1.7℃, with
the maximum temperature occurring in July (9.8 ℃) and the minimum
temperature occurring in January (-14.80℃) (Dai, et al., 2021). Alpine
shrubs and meadows are the dominant vegetation types at the study sites.
The dominant primary vegetation is the shrub P. fruticose ; herbs
include Elymus nutans, Poaprsten, Kobresia humilis, Double-stigma
Bulrush, and Polygonum vivipsrum . The characteristics of the
community were investigated and shown in Table 1.
Table1 Community characteristics of grassland and shrub sites.