Zhang Zhenchao, Zhao Yiran, Lin Hao, Li Yanpeng, Fu Jinmin, Wang Yingxin, Sun Juan, Zhao Yanhua
Key Laboratory of National Forestry and Grassland Administration on Grassland Resources and Ecology in the Yellow River Delta, College of Grassland Science, Qingdao Agricultural University, Qingdao, Shandong, China.
School of Mapping and Geographic Information, Jiangxi College of Applied Technology, Ganzhou, China.
Front Plant Sci. 2023 Jan 17;13:1083709. doi: 10.3389/fpls.2022.1083709. eCollection 2022.
Livestock grazing is a dominant practice in alpine grasslands and plays a crucial role in the ecosystem service of the Qinghai-Tibetan Plateau. The effects of grazing on alpine grasslands highly depends on grazing intensity. Up to now, we still lack comprehensive understanding of the general responses of alpine grasslands to different grazing intensities over broad geographic scales across the Qinghai-Tibetan Plateau. Here, we conducted a meta-analysis to explore the responses of plant characteristics and soil properties to grazing intensity in alpine grasslands of the Qinghai-Tibetan Plateau based on 52 peer-reviewed literatures. The results showed that grazing did not change the belowground biomass, while significantly increased the ratio of root to shoot ( 0.05). Light grazing exhibited no significant effects on the plant richness, Shannon-Wiener diversity, soil water content, soil bulk density, nutrients, microbial biomass carbon, and microbial biomass nitrogen ( > 0.05). Moderate grazing significantly increased the plant richness and Shannon-Wiener diversity, while significantly decreased the soil organic carbon and total nitrogen ( 0.05). Heavy grazing significantly decreased the plant richness, Shannon-Wiener diversity, water content, soil organic carbon, total nitrogen, microbial biomass carbon, and microbial biomass nitrogen, and significantly increased the soil bulk density ( 0.05). These findings suggest that overgrazing is closely associated with grassland degradation, and moderate grazing is a sustainable practice to provide animal production and simultaneously maintain ecological functions for alpine grasslands on the Qinghai-Tibetan Plateau.
牲畜放牧是高寒草原的主要利用方式，在青藏高原生态系统服务中发挥着关键作用。放牧对高寒草原的影响高度依赖于放牧强度。截至目前，我们仍缺乏对青藏高原广大地理尺度上高寒草原对不同放牧强度的总体响应的全面认识。在此，我们基于52篇同行评议文献进行了一项荟萃分析，以探究青藏高原高寒草原植物特征和土壤性质对放牧强度的响应。结果表明，放牧并未改变地下生物量，但显著增加了根冠比（P<0.05）。轻度放牧对植物丰富度、香农-威纳多样性、土壤含水量、土壤容重、养分、微生物生物量碳和微生物生物量氮均无显著影响（P>0.05）。中度放牧显著增加了植物丰富度和香农-威纳多样性，但显著降低了土壤有机碳和全氮（P<0.05）。重度放牧显著降低了植物丰富度、香农-威纳多样性、含水量、土壤有机碳、全氮、微生物生物量碳和微生物生物量氮，并显著增加了土壤容重（P<0.05）。这些发现表明，过度放牧与草地退化密切相关，适度放牧是一种既能提供畜牧生产又能同时维持青藏高原高寒草原生态功能的可持续利用方式。
