Plant community stability, indicator species and their driving factors at a gradient of grazing intensity in an alpine meadow

Abstract

On the Tibetan Plateau, most alpine meadows have undergone various degree of degradation due to heavy grazing practices. Assessing the progress of grazing succession, identify the indicator species for different grazing managements is crucial to facilitate the effective restoration of degraded alpine meadows. In this study, specific areas with varying levels of grazing intensity were selected to assess the stability of plant communities, to identify the indicator species for each stage, and to examine the driving factors influencing community stability. The results showed that (i) plant community stability was found to be highest under light and moderate levels of grazing. In comparison to heavy grazing treatment, the community “cohesion” index (|Negative cohesion|) increased by 54.45% under light grazing treatment and by 23.24% under moderate grazing treatment. (ii) the indicator species varied across different succession stages and played distinct roles. Dominant species were identified as indicator species with no grazing and light grazing treatment, whereas rare poisonous species served as indicators under heavy grazing treatment. (iii) the driving factors and mechanisms influencing community stability differed throughout gradient of grazing intensity. Plant-related factors primarily influenced community stability under light grazing, while soil-related factors began to play a joint role under heavy grazing. This empirical knowledge contributes to establishing a scientific basis for the rational utilization and management of alpine meadow ecosystems.

Keywords

• Grazing intensity
• Average variation degree
• Cohesion index
• Indicator species
• Driving factors
• Alpine meadow