Understanding the dynamic process of community diversity after grazing exclusion is crucial for the management and conservation of alpine grassland ecosystems. This study conducted a ten‐year grazing exclusion experiment across four altitudinal gradients on Mount Gongga, ranging from 3000 to 4130 m, and surveyed community diversity during the years 2012–2016, 2020, and 2022. Several key findings were revealed: (1) the linear mixed‐effects models showed that the interaction between altitude and time was significantly correlated with α‐diversity, which decrease during the long‐term grazing exclusion period across all altitudes. However, the changes in community composition at low altitudes occurred at a slower pace compared to those at higher altitudes; (2) across all altitudes, β‐diversity significantly increased under long‐term grazing exclusion compared to short‐term grazing exclusion, primarily due to species replacement, as evidenced by the seven newly emerged species observed in 2022 relative to 2012; and (3) overall, the coverage of livestock‐favored plants, including sedges (Cyperaceae) and grasses (Poaceae), has increased under long‐term grazing exclusion, whereas the coverage of other forbs has declined. Pioneer species (e.g., Potentilla leuconota and Plantago asiatica) played a crucial role at low altitudes. These results highlight the complexity of ecological replacement and how factors such as altitude and grazing exclusion influence the dynamics and composition of alpine grassland communities over time.

中文翻译：

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放牧排斥对草地群落多样性的影响沿海拔梯度变化——以贡嘎山为例


了解放牧排斥后群落多样性的动态过程对于高寒草原生态系统的管理和保护至关重要。本研究在 3000 至 4130 m 的贡嘎山 4 个海拔梯度上进行了为期 10 年的放牧排斥实验，并调查了 2012—2016 年、2020 年和 2022 年的群落多样性。揭示了几个关键发现：（1） 线性混合效应模型表明，海拔和时间之间的交互作用与α多样性显著相关，在所有海拔的长期放牧排除期内，多样性都会降低。然而，与高海拔相比，低海拔群落组成的变化速度较慢;（2） 在所有海拔地区，与短期放牧相比，长期放牧排除下的β多样性显着增加，这主要是由于物种更替，2022 年相对于 2012 年观察到的 7 个新出现的物种证明了这一点;（3） 总体而言，在长期放牧排除下，包括莎草 （Cyperaceae） 和草 （Poaceae） 在内的畜牧植物的覆盖率有所增加，而其他杂草的覆盖率则有所下降。先锋物种（例如 Potentilla leuconota 和 Plantago asiatica）在低海拔地区起着至关重要的作用。这些结果突出了生态替代的复杂性，以及海拔和放牧排斥等因素如何随着时间的推移影响高山草原群落的动态和组成。