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Acta Prataculturae Sinica ›› 2025, Vol. 34 ›› Issue (11): 17-30.DOI: 10.11686/cyxb2024523

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Effects of the duration of grazing exclusion on plant communities in alpine grassland

Cong HE1(), Yong-cai MA2, Hong-biao ZI1()   

  1. 1.State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems,College of Pastoral Agriculture Science and Technology,Lanzhou University,Lanzhou 730020,China
    2.Gannan Prefecture Animal Husbandry Comprehensive Experimental Field,Gannan 747000,China
  • Received:2024-12-30 Revised:2025-03-03 Online:2025-11-20 Published:2025-10-09
  • Contact: Hong-biao ZI

Abstract:

Large herbivores strongly influence plant communities and ecosystem processes in a variety of habitats. In this study, fencing was used to simulate the loss of large herbivores, and the “space-for-time substitutions” method was adopted to study the structure, aboveground net primary productivity, diversity and productivity-diversity relationships of alpine grassland plant communities after exclusion of grazers for different durations (0, 3, 5, 8, 10 years) in Haibei, Qinghai. The results show that: 1) Grazing exclusion significantly changed the plant community structure of alpine grassland. With longer periods of grazing exclusion, the proportion of grasses in the community gradually increased, while the proportions of other functional groups (legumes, sedges, and forbs) gradually decreased, and internal heterogeneity within the communities gradually increased. 2) The aboveground net primary productivity of the plant communities initially decreased and then increased as the duration of grazing exclusion extended, while litter mass showed the opposite trend. Grazing exclusion generally reduced species diversity, functional diversity, and phylogenetic diversity. 3) There was a significant negative correlation between aboveground net primary productivity and Pielou’s evenness index, Simpson’s dominance index, Rao’s quadratic entropy index, and mean nearest taxon distance, but no significant correlations with other diversity indices. These results indicate that the loss of large herbivores will significantly impact grassland ecosystems, particularly those in good health. Therefore, grazing exclusion should be carefully formulated based on the actual situation of grasslands.

Key words: alpine grassland, grazing exclusion, herbivores, diversity, productivity