Effects of grazing on vegetation diversity
The linear fitting analysis of the vegetation diversity index and
grazing gradient in different sites showed that the diversity index of
five sites in the dry season and four sites in the rainy season (except
for SP) were inversely proportional to grazing intensity (Figure 2),
indicating that vegetation diversity was generally lost in the dry
season under grazing pressure. The slope of Pielou index is lower than
that of Simpson and Shannon. In addition, the relationship between
diversity and grazing pressure was different between sites and seasons
(Figure 2). Among them, DL (DT=0.1 ℃, RT=4.69 ℃, DP=118.8 mm, RP=306.7
mm) in wet and cold climate had the lowest slope with the increase of
grazing pressure in both dry and rainy seasons. SP (DT= 7.37 ℃, RT=11.01
℃, DP=62.5 mm, RP=139.8 mm) belongs to the warm-dry climate type, and
the relationship between vegetation diversity index and grazing
intensity is obvious seasonality, which is inversely proportional in the
dry season and directly proportional in the rainy season.