Grazing is a major driving force of biodiversity, functions and stability of alpine meadows. In selenium-deficient alpine meadows, moderate selenium supplementation can promote plant growth and increase selenium content within the food web. However, the combined effect of grazing and selenium (Se) addition on the stability of alpine meadow communities within selenium-deficient soil is still unclear. Therefore, we conducted a three-year experiment in an alpine meadow of Qinghai-Tibetan Plateau (QTP), with two stocking rates (0 and 6 sheep months ha) and six levels of Se addition (0, 5, 10, 20, 40 and 80 g ha) to explore how grazing and Se addition affect community stability and its relationship with species richness, species asynchrony and functional group stability. Results showed that the community stability, species richness and biomass response ratio of the community increased gradually with the increase in the selenium application under grazing and enclosure treatments, reaching the maximum values at 20 g ha. However, when the selenium addition exceeded 20 g ha, the above mentioned indexes were decreased gradually, especially under grazing. Structural equation model showed that grazing and selenium addition indirectly affected the temporal stability of sedges and forbs, thus influencing the temporal stability of the community. Results of this study indicated that the alpine meadow can maintain high species diversity and community temporal stability under moderate grazing combined with selenium addition, providing a scientific basis for selenium-enriched grazing management in alpine meadows.

中文翻译：

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放牧和硒通过增加异步性和莎草、草丛稳定性影响青藏高原高寒草甸群落稳定性


放牧是高寒草甸生物多样性、功能和稳定性的主要驱动力。在缺硒的高寒草甸，适量补硒可以促进植物生长，增加食物网中的硒含量。然而，放牧和硒（Se）添加对缺硒土壤中高寒草甸群落稳定性的综合影响仍不清楚。因此，我们在青藏高原高寒草甸进行了为期三年的试验，两种放养率（0和6只羊月公顷）和六个硒添加水平（0、5、10、20、40）和80克公顷）探讨放牧和硒添加如何影响群落稳定性及其与物种丰富度、物种异步性和功能群稳定性的关系。结果表明，放牧和围封处理下，随着施硒量的增加，群落稳定性、物种丰富度和生物量响应比逐渐增加，在20 g ha时达到最大值。但当硒添加量超过20 g ha时，上述指标逐渐下降，特别是在放牧条件下。结构方程模型表明，放牧和硒添加间接影响莎草和杂草的时间稳定性，从而影响群落的时间稳定性。研究结果表明，适度放牧结合补硒条件下，高寒草甸能够保持较高的物种多样性和群落时间稳定性，为高寒草甸富硒放牧管理提供科学依据。