关键词: 划区轮牧, 植物群落, 物种多样性, 凋落物, 荒漠草原

Abstract: Studying the effects of different grazing regimes on grassland vegetation characteristics can provide a scientific basis for optimizing grassland grazing practice. In the desert steppe of Ningxia, grazing exclusion was used as a control (CK), and was compared with continuous grazing (CG), two-paddock rotational grazing (TG), four-paddock rotational grazing (FG), and six-paddock rotational grazing (SG) at a sheep stocking rate of 0.75 head·ha^-1 during the growing season. Measurements made included vegetation composition, community cover, biomass, net primary productivity, species diversity, and biological stability of the community. The results showed that: 1) Rotational grazing decreased the importance value of the preferred forage species in the desert steppe plant community, but increased the number of plant species. Increasing the number of paddocks in the grazing rotation helped to maintain the importance values of preferred forage species and perennial herbs, but had little impact on the semi-shrubs. 2) The vegetation cover was, as expected, higher in the CK treatment and was also elevated in the FG treatment. The above-ground biomass and net primary productivity were higher in the FG and SG rotational grazing plots, and the underground biomass was higher in CK and SG treatments. The amount of grassland litter under rotational grazing was higher than that in the CK treatment. 3) Rotational grazing increased species richness, diversity and dominance index, while decreasing the community evenness index. 4) Under all treatments, the plant community was unstable. However, the CK plots displayed the highest stability, and CG had the lowest stability. Based on all the vegetation data collected and ease of operation of the grazing system, it is considered that the FG rotational grazing system is an appropriate grazing regime for the study area.

Key words: rotational grazing, plant community, species diversity, litters, desert steppe