Relationships and Changes of Grassland Community Diversity and Biomass in the Pasture Area of the Two Rivers Under Grazing Disturbance
Grazing affects the characteristics of plant communities and the relationship between above-ground biomass and diversity,which has been become a hot issue in grassland ecosystem research in recent years.In this study,we investigated the grassland vegetation in the pasture area of the two river sources based on the data collected from 60 sampling points,and used the sampling method to analyze the effects of grazing on the structural characteristics of plant communities using the α-diversity index,and to explore the relationship between species diversity and above-ground biomass(AGB)of plant communities and their changes.The results showed that 1)under natural grazing conditions that may result over stocking,the number of plant families and genera in the pasture area of the two river sources decreased,the height and cover of the plant community showed a decreasing trend(P<0.01),and the density showed an increasing trend(P<0.01).2)Grazing significantly reduced the AGB of plant communities(P<0.01).The AGB of the grass community decreased,the AGB of the weed community increased and the AGB of the legume community did not change significantly.3)Grazing had a significant impact on the plant communities in the pastoral areas of the two river sources,resulting in a decrease in species richness,dominance and diver-sity of the plant communities,but a more even distribution of the number of community species.4)The AGB of plant communities showed highly significant and positive correlations with Margalef's richness in-dex,Shannon-Wiener's diversity index and Alatalo's evenness index(P<0.01),and highly significant and negative correlations with Simpson's dominance index(P<0.01).The relationship between AGB and plant community species diversity remained significant under grazing disturbance.Therefore,in grassland man-agement and conservation,the effect of grazing on the structural characteristics of plant communities should be taken into account,and appropriate response policies should be made according to the actual local situation.This study provides a theoretical basis for grassland conservation,management and sustainable development of ecosystems in the pastoral areas of the two river basins.
grazingplant community structurediversity indexabove-ground biomasstwo rivers pastoral area
万方数据
维普
