不同放牧管理方式对新疆山地草原植物群落特征的影响

Mountain grassland are an essential component of pasture resources in the Xinjiang UygurAutonomous Region. However, mountain grassland are highly vulnerable to human-associated disturbance andclimate change. The responses of the mountain grassland plant community characteristics and diversity todifferent grazing managements in Barkol County, Xinjiang, are still unclear. In this study, three different grazingmanagement treatments were set up in 2012 to investigate the response patterns of the plant communitycharacteristics, diversity, and the relationship between the diversity and the aboveground biomass in the mountaingrasslands. The three grazing management blocks were M0, M1, and M2, which represented the permanentgrazing prohibition, winter grazing, and year-round grazing management, respectively. During the peak growingseasons of 2013, 2017, and 2022, the data regarding the number of species, height, coverage, density, andaboveground plant biomass were collected for further analysis. The results indicated that the different grazingmanagements had no significant impacts on the importance value of the dominant species, such as Stipa glareosa.However, the importance values of the nondominant species such as Neotrinia splendens and Achnatheruminebrians (Hance) Keng increased under winter and year- round grazing. As grazing intensity increased, plantheight, coverage, density, aboveground biomass, and their response ratios declined significantly (P<0.05). Therewere no significant differences in the Shannon- Wiener diversity, Simpson dominance, and Pielou evennessindices in M0, M1, and M2. In contrast, the Margalef richness index elevated markedly (P<0.05), indicating thatgrazing provided more survival resources helpful for other species. In the permanent grazing prohibition block,the aboveground biomass was negatively correlated with the Simpson dominance, Shannon-Wiener diversity, andPielou evenness indices. In the winter grazing block, aboveground biomass was negatively correlated with theMargalef richness index. Overall, the importance value of the dominant species showed no remarkabledifferences under varying grazing management, and its dominance remained unchanged. Except for the Margalefrichness index, the other diversity indices were not significantly influenced by grazing. Winter and year- roundgrazing enhanced the vital value of unpalatable species, altering the composition of forage, which was notconducive to future animal husbandry development. In summary, as the enclosure time increased, permanentgrazing prohibition was beneficial for restoring degraded grasslands, improving community characteristic values,improving grassland productivity, and maintaining community stability to a certain extent. Grazing would affectresource redistribution in the ecosystem, releasing ecological niches for more species, but year-round grazing ledto intensified grassland degradation because of overgrazing pressure.