Characteristics of plant functional groups and the relationships with soil environmental factors in middle part of northern slope of Tianshan Mountains under different grazing intensities
Aims Despite grazing being a significant driving factor for grassland ecosystems,it remains uncertain whether the responses of grassland plant communities and functional groups to soil variables remain consistent across grazing intensity gradients.Methods This study conducted field plant community surveys in the middle part of the northern slope of Tianshan Mountains,and lab soil analysis.It aimed to analyze the impact of grazing on plant communities and functional groups,as well as reveal differences in their responses to soil factors under grazing intensity.Important findings The results indicated that perennial grasses and sedges were the main dominant functional groups in light grazing and no grazing sites.However,heavy grazing sites had poisonous grasses as dominant functional groups,with Achnatherum inebrians being the dominant species.Light grazing significantly increased above-ground biomass for functional groups such as perennial grasses,legumes,sedges,and forbs while notably decreased for poison grasses compared to heavy grazing along the gradient.In terms of functional group diversity,Shannon-Wiener index,Margalef index,and Pielou index were significantly higher under light grazing than heavy grazing;however,Simpson index did not show significant differences between different levels of grazing intensity.Results from redundancy analysis,Mantel test,and structural equation models demonstrated significant correlations between plant community characteristics(including functional groups),community diversity indices(Shannon-Wiener index),and various soil factors such as organic carbon content,available nitrogen content,available potassium content,total phosphorus content,total potassium content,soil density,soil water content.Grazing directly exerted a significant negative impact on grassland height,coverage,density,aboveground biomass,diversity within both plant communities and functional groups.The soil density increase and soil nutrient reduction caused by grazing can also impact community height,coverage,density,above-ground biomass,as well as the diversity of plant community and functional groups.In summary,soil factors played a pivotal role in maintaining the stable growth of grassland plant communities amidst grazing disturbance in middle part of northern slope of Tianshan Mountains.The findings provide a scientific foundation for the rational utilization of grassland plant resources in Xinjiang.
NETL
NSTL
万方数据
