Abstract:
Although grazing is the most common use of grassland, the ecological
function of grassland far exceeds its productivity. Therefore, the protection
of plant diversity is of the utmost importance and cannot be ignored. Existing
research on the effect of grazing on grassland mainly focuses on grazing
intensity and the type of livestock, but the consequences of the timing of the
grazing on the vegetation community remains unclear. We investigated plant
community characteristics of winter pastures in alpine meadow with different
grazing termination times (grazing before and during the grassland greenup
periods) in Maqu County, eastern QTP. The results showed that vegetation
height, coverage, aboveground biomass and Graminoid biomass were lower
in grassland when grazing happened during the greenup period compared
to grassland where grazing was terminated before the greenup period.
However, the total plant species richness and forbs richness were higher in
grassland with grazing during the greenup period compared to grassland
without grazing during the greenup period. Our structural equation modeling
reveals a potential indirect implication for the total plant species richness and
forbs richness of winter pastures mainly through a decrease in the vegetation
coverage and grass biomass abundance. Our findings imply that grazing
during the grassland greenup period may facilitate the maintenance of plant
diversity in winter pastures. These findings have important implications for
grassland ecosystem functioning and for the conservation of plant diversity.
