Patchiness acts as an indicator of terrestrial ecosystem degradation and can lead to considerable loss of soil organic carbon and total nitrogen. However, quantitative assessments of the effects of patchiness on soil organic carbon and total nitrogen stocks and their associated mechanisms remain limited. This study aimed to explore the influence mechanisms of patchiness on soil organic carbon and total nitrogen stocks and to project the quantitative contribution of the further expansion of patchiness and vegetation recovery. Soil properties, soil organic carbon and total nitrogen stocks were investigated using a combination of field sampling and aerial photography in four grassland types, alpine meadow, alpine steppe, temperate grassland, and desert grassland, at 47 sites in northwestern China. Soil organic carbon and total nitrogen densities in the bare patches were 34–54 % and 23–41 % lower, respectively, compared to the original vegetation. At the plot-scale, current soil organic carbon and total nitrogen stocks ranged from 30.85 to 77.80 T/ha and 3.26 to 10.19 T/ha, respectively, across grassland types; with a 10–27 % and 7–24 % potential loss of soil organic carbon and total nitrogen stocks, respectively, from the further expansion of patchiness but a 10–50 % and 9–37 % potential increase in soil organic carbon and total nitrogen stocks, respectively, from vegetation recovery. Soil organic carbon and total nitrogen stocks were positively correlated with vegetation biomass, soil clay content, and precipitation (p < 0.001), whereas they were negatively correlated with patchiness (p < 0.001). In summary, patchiness reduced soil organic carbon and total nitrogen stocks by decreasing vegetation inputs and increasing erosion outputs, while vegetation recovery showed potential for increasing carbon and nitrogen stocks. Our results highlight that maintaining intact vegetation cover is critical for preserving terrestrial ecosystem carbon and nitrogen storage.

中文翻译：

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植被恢复可以抵消由片状驱动的土壤有机碳和总氮损失

斑块状是陆地生态系统退化的一个指标，可能导致土壤有机碳和总氮的大量损失。然而，斑块对土壤有机碳和总氮储量的影响及其相关机制的定量评估仍然有限。本研究旨在探讨斑块状对土壤有机碳和全氮储量的影响机制，并预测斑块状进一步扩大和植被恢复的定量贡献。采用野外采样和航空摄影相结合的方法，对西北地区47个点的高寒草甸、高寒草原、温带草原和荒漠草原4种草原类型的土壤性质、土壤有机碳和全氮储量进行了调查。与原始植被相比，裸露斑块的土壤有机碳和总氮密度分别降低了 34-54% 和 23-41%。在地块尺度上，目前不同草地类型的土壤有机碳和总氮储量分别为 30.85 至 77.80 吨/公顷和 3.26 至 10.19 吨/公顷；由于斑块的进一步扩大，土壤有机碳和总氮储量分别潜在损失 10-27% 和 7-24%，但土壤有机碳和总氮潜在增加 10-50% 和 9-37%分别来自植被恢复的库存。土壤有机碳和总氮储量与植被生物量、土壤粘土含量和降水量呈正相关（p < 0.001），而与斑块状呈负相关（p < 0.001）。总之，斑块状区域通过减少植被输入和增加侵蚀输出来减少土壤有机碳和总氮储量，而植被恢复则显示出增加碳和氮储量的潜力。我们的研究结果强调，保持完整的植被覆盖对于保护陆地生态系统碳和氮储存至关重要。