The Effects of Different Grazing Periods on the Functional Traits of Leymus chinensis (Trin.) Tzvelev in a Typical Inner Mongolia Steppe

Plant functional traits are effective indicators and predictors of environmental change, revealing plants’ ecological countermeasures and adaptability through phenotypic plasticity. We conducted a 6-year grazing experiment on typical temperate grassland to assess the impact of different grazing periods on the plasticity and variability of the functional traits of Leymus chinensis and the relationship between traits and individual plant biomass. Our study included four treatments: CK (enclosure), T1 (grazing in May and July), T2 (grazing in June and August), and T3 (grazing in July and September). The results for 13 functional traits indicated that the T3 treatment showed the smallest reduction in individual plant biomass, plant height, leaf area, stem length, and leaf length, making it the most effective type of grassland management and optimal for the maintenance and restoration of L. chinensis traits. Under T1, T2, and T3, the plasticity of stem weight, total leaf weight, total leaf area, and stem length was higher and crucial for regulating individual plant biomass. The results underscore that the changes and plasticity of dominant species under grazing treatments are key to understanding the relationship between ecosystem function and grassland management. This study provides a theoretical basis and data support for the adaptive utilization and restoration management of typical grassland resources.