Data_Sheet_1_Effects of Different Grazing Disturbances on the Plant Diversity and Ecological Functions of Alpine Grassland Ecosystem on the Qinghai-Tibetan Plateau.docx

Grazing is one of the main human disturbance factors in alpine grassland on the Qinghai-Tibet Plateau (QTP), which can directly or indirectly influence the community structures and ecological functions of grassland ecosystems. However, despite extensive field grazing experiments, there is currently no consensus on how different grazing management approaches affect alpine grassland diversity, soil carbon (C), and nitrogen (N). Here, we conducted a meta-analysis of 70 peer-reviewed publications to evaluate the general response of 11 variables related to alpine grassland ecosystems plant diversity and ecological functions to grazing. Overall, the results showed that grazing significantly increased the species richness, Shannon–Wiener index, and Pielou evenness index values by 9.89% (95% CI: 2.75–17.09%), 7.28% (95% CI: 1.68–13.62%), and 3.74% (95% CI: 1.40–6.52%), respectively. Aboveground biomass (AGB) and belowground biomass (BGB) decreased, respectively, by 41.91% (95% CI: −50.91 to −32.88%) and 17.68% (95% CI: −26.94 to −8.52%). Soil organic carbon (SOC), soil total nitrogen (TN), soil C:N ratio, and soil moisture decreased by 13.06% (95% CI: −15.88 to −10.15%), 12.62% (95% CI: −13.35 to −8.61%), 3.27% (95% CI: −4.25 to −2.09%), and 20.75% (95% CI: −27.89 to −13.61%), respectively, whereas, soil bulk density and soil pH increased by 17.46% (95% CI: 11.88–24.53%) and 2.24% (95% CI: 1.01–3.64%), respectively. Specifically, moderate grazing, long-durations (>5 years), and winter grazing contributed to increases in the species richness, Shannon–Wiener index, and Pielou evenness index. However, AGB, BGB, SOC, TN, and soil C:N ratios showed a decrease with enhanced grazing intensity. The response ratio of SOC was positively associated with AGB and BGB but was negatively related to the Shannon–Wiener index and Pielou evenness index. Furthermore, the effects of grazing on plant diversity, AGB, BGB, SOC, and TN in alpine grassland varied with grazing duration, grazing season, livestock type, and grassland type. The findings suggest that grazing should synthesize other appropriate grazing patterns, such as seasonal and rotation grazing, and, furthermore, additional research on grazing management of alpine grassland on the QTP is needed in the future.

放牧行为系青藏高原（QTP）高山草原生态系统的主要人为干扰因素之一，其可直接影响或间接作用于草原生态系统的群落结构和生态功能。尽管广泛开展了实地放牧实验，但对于不同放牧管理方法对高山草原多样性、土壤碳（C）和氮（N）的影响，目前尚无共识。本研究通过元分析70篇同行评审的出版物，旨在评估11个与高山草原生态系统植物多样性和生态功能相关的变量对放牧的一般响应。总体而言，结果表明放牧显著提升了物种丰富度、香农-威纳指数和皮尔卢均匀度指数，分别增加了9.89%（95%置信区间：2.75–17.09%）、7.28%（95%置信区间：1.68–13.62%）和3.74%（95%置信区间：1.40–6.52%）。地上生物量（AGB）和地下生物量（BGB）分别下降了41.91%（95%置信区间：−50.91至−32.88%）和17.68%（95%置信区间：−26.94至−8.52%）。土壤有机碳（SOC）、土壤全氮（TN）、土壤碳氮比和土壤湿度分别下降了13.06%（95%置信区间：−15.88至−10.15%）、12.62%（95%置信区间：−13.35至−8.61%）、3.27%（95%置信区间：−4.25至−2.09%）和20.75%（95%置信区间：−27.89至−13.61%），而土壤容重和土壤pH值则分别上升了17.46%（95%置信区间：11.88–24.53%）和2.24%（95%置信区间：1.01–3.64%）。具体而言，适度放牧、长期放牧（>5年）和冬季放牧有助于物种丰富度、香农-威纳指数和皮尔卢均匀度指数的提高。然而，随着放牧强度的增强，AGB、BGB、SOC、TN和土壤碳氮比均表现出下降趋势。SOC的响应比率与AGB和BGB呈正相关，但与香农-威纳指数和皮尔卢均匀度指数呈负相关。此外，放牧对高山草原植物多样性、AGB、BGB、SOC和TN的影响因放牧持续时间、放牧季节、牲畜类型和草原类型而异。研究结果表明，放牧应综合其他适宜的放牧模式，如季节性放牧和轮牧，并且未来有必要对青藏高原高山草原的放牧管理进行更深入的研究。