Study site
We selected five grassland pastures located in northwest China, namely
Duo lun (DL), Er er duo si (EE), Hai La er (HL), Sha po tou (SP), Wu lan
aodu (WA). The pastures chosen were far from urban industrial areas and
had little human activity other than grazing. Climatic conditions are
reflected by four indicators: dry season temperature (DT), dry season
precipitation (DP), rainy season temperature (RT) and rainy season
precipitation (RP). DL (DT=0.1 ℃, RT=4.69 ℃, DP=118.8 mm, RP=306.7 mm),
EE (DT= 4.78 ℃, RT=8.88 ℃, DP=98.3 mm, RP=280.1 mm), HL (DT= 5.77 ℃,
RT=9.94 ℃, DP=40.1 mm, RP=104.5 mm), SP (DT= 7.37 ℃, RT=11.01 ℃, DP=62.5
mm, RP=139.8 mm), WA (DT=5.77 ℃, RT=9.94 ℃, DP=40.1 mm, RP=104.5 mm). In
the pasture, different grazing intensity locations were selected to set
the quadrat. Grazing intensity was divided according to dry season
vegetation cover (DVC) and rainy season vegetation cover (RVC). The
control group (grazing intensity 0, DVC> 60%,
RVC> 70%) and four gradients of different grazing
intensities, namely 1
(45%<DVC<60%、55%<RVC<70%),
2
(30%<DVC<45%、40%<RVC<55%),
3
(15%<DVC<30%、20%<RVC<40%),
and 4 (DVC<15%、RVC<20%). Plant species were
identified and counted in five replicate quadrats for each grazing
intensity at each site.