Until now, nearly 90% of alpine grasslands on the Qinghai‐Tibetan Plateau (QTP) have been degraded. However, there is currently no consensus on how soil organic carbon (SOC) and soil total nitrogen (STN) stocks vary with the degradation succession of alpine grasslands in this region. Here, a meta‐analysis was conducted to quantify the dynamics of SOC and STN stocks in topsoil (0–30 cm) at different degradation stages of alpine grasslands on the QTP. The results showed that grassland degradation led to average losses of 48 and 39% for SOC and STN stocks, respectively. The changes in SOC and STN stocks following grassland degradation did not differ significantly between grassland types, but were significantly affected by grassland degradation stage. The reductions in both SOC and STN stocks increased with the degradation stage, and the highest reductions were all found at extreme degradation stage. The results indicated that the depletion of SOC and STN pools were aggravated with the degradation succession of grassland. The tightly coupled SOC and STN implied that the depletion of SOC stock was closely related to that of STN stock during the process of grassland degradation. Positive relationships were detected between the dynamics of vegetation coverage and that of SOC or STN stock, indicating that vegetation coverage could not only reflect grassland degradation, but might also be a potential indicator of SOC and STN status. The findings suggest that preventing the degradation succession of alpine grasslands is vital to maintain or promote SOC and STN levels on the QTP.

中文翻译：

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青藏高原高寒草地退化后土壤碳氮储量的变化：Meta分析

到现在为止，青藏高原（QTP）上近90％的高山草原已经退化。但是，目前尚无关于该地区高寒草地退化演替中土壤有机碳（SOC）和土壤总氮（STN）储量如何变化的共识。在这里，进行了荟萃分析，以量化QTP上高寒草地不同退化阶段表土（0–30 cm）中SOC和STN储量的动态。结果表明，草地退化导致SOC和STN库存分别平均减少48％和39％。草地退化后SOC和STN储量的变化在草地类型之间没有显着差异，但是受到草地退化阶段的显着影响。SOC和STN库存量的减少都随着降解阶段的增加而增加，在极端降解阶段发现的还原量最高。结果表明，SOC和STN库的耗竭加剧了草地的退化演替。SOC和STN的紧密耦合表明，草地退化过程中SOC的消耗与STN的消耗密切相关。植被覆盖度动态与SOC或STN种群动态之间存在正相关关系，表明植被覆盖度不仅可以反映草地退化，而且可能是SOC和STN状况的潜在指标。研究结果表明，防止高寒草原退化演替对于维持或促进QTP上的SOC和STN水平至关重要。结果表明，SOC和STN库的耗竭加剧了草地的退化演替。SOC和STN的紧密耦合表明，草地退化过程中SOC的消耗与STN的消耗密切相关。植被覆盖度动态与SOC或STN种群动态之间存在正相关关系，表明植被覆盖度不仅可以反映草地退化，而且可能是SOC和STN状况的潜在指标。研究结果表明，防止高寒草原退化演替对于维持或促进QTP上的SOC和STN水平至关重要。结果表明，SOC和STN库的耗竭加剧了草地的退化演替。SOC和STN的紧密耦合表明，草地退化过程中SOC的消耗与STN的消耗密切相关。植被覆盖度动态与SOC或STN种群动态之间存在正相关关系，表明植被覆盖度不仅可以反映草地退化，而且可能是SOC和STN状况的潜在指标。研究结果表明，防止高寒草原退化演替对于维持或促进QTP上的SOC和STN水平至关重要。SOC和STN的紧密耦合表明，草地退化过程中SOC的消耗与STN的消耗密切相关。植被覆盖度动态与SOC或STN种群动态之间存在正相关关系，表明植被覆盖度不仅可以反映草地退化，而且可能是SOC和STN状况的潜在指标。研究结果表明，防止高寒草原退化演替对于维持或促进QTP上的SOC和STN水平至关重要。SOC和STN的紧密耦合表明，草地退化过程中SOC的消耗与STN的消耗密切相关。植被覆盖度动态与SOC或STN种群动态之间存在正相关关系，表明植被覆盖度不仅可以反映草地退化，而且可能是SOC和STN状况的潜在指标。研究结果表明，防止高寒草原退化演替对于维持或促进QTP上的SOC和STN水平至关重要。但也可能是SOC和STN状态的潜在指标。研究结果表明，防止高寒草原退化演替对于维持或促进QTP上的SOC和STN水平至关重要。但也可能是SOC和STN状态的潜在指标。研究结果表明，防止高寒草原退化演替对于维持或促进QTP上的SOC和STN水平至关重要。