Abstract: To investigate the impact of alpine meadow degradation on vegetation community， in this study we analyzed habitat， biomass， diversity， and community structure differences within the context of alpine meadow succession to alpine steppe. Additionally， we explored the driving factors of diversity and community differences. The results showed that as alpine meadows were degraded into alpine steppes， precipitation significantly was decreased （P<0.05）， temperature significantly was increased （P<0.05）， soil pH value significantly raised （P<0.05）， and soil nutrients were depleted. Biomass significantly was declined （P<0.05）， species richness of vegetation significantly were decreased （P<0.01）， and community differences became pronounced （P<0.001）. Furthermore， multi-year average precipitation significantly promoted vegetation diversity （P<0.01）， while grazing had a significant negative impact （P<0.05）. Habitat accounted for 64% of the changes in vegetation communities. Multiple regression and hierarchical partitioning indicated that grazing， altitude， precipitation， and soil organic matter were the main factors regulating changes of vegetation communities （P<0.01）. In summary， adjusting grazing management， protecting water resources， and improving soil conditions are crucial measures to maintain biodiversity in grassland ecosystems.

Key words: Alpine meadow, Degradation, Multiple regression, Hierarchical partitioning

摘要： 为探讨高寒草甸退化对植被群落的影响，本研究以高寒草甸逐渐退化并演替为高寒草原的过程为研究背景，分析了植被群落的生境、生物量、多样性和群落结构差异，并探索了多样性和群落差异的驱动因子。结果表明：从高寒草甸退化为高寒草原，降水显著减少（P<0.05），气温显著升高（P<0.05），土壤pH值显著升高（P<0.05），土壤养分流失；生物量显著下降（P<0.05）；植被物种丰富度显著下降（P<0.01），群落差异显著（P<0.001）。同时，年平均降水对植被多样性有显著促进作用（P<0.01），而放牧对其有显著负面影响（P<0.05）。此外，生境解释了植被群落变化的64%，多元回归和层次分割法表明，放牧、海拔、降水及土壤有机质含量是植被群落变化的主要调节因子（P<0.01）。综上，调控放牧压力、加强水资源保护以及改善土壤状况，是防止草地退化和保持生物多样性的重要策略。

关键词: 高寒草甸, 退化, 多元回归, 层次分割