基于Meta分析的放牧对黄土高原草地生态系统的影响

Effects of Grazing on Grassland Ecosystem on the Loess Plateau Based on A Meta-Analysis

为明确放牧对黄土高原草地生态系统的整体影响,本文对39篇相关文献进行Meta分析,探讨了放牧对黄土高原草地植被、土壤理化性质和土壤微生物的影响,并进一步分析了影响其放牧效应的相关因素。结果表明:放牧对黄土高原草地植物多样性、土壤细菌丰度和放线菌丰度以及土壤微生物总丰度没有显著影响,但却显著降低了草地的生产力和土壤碳氮磷养分,明显增加了土壤容重、pH值和土壤真菌相对丰度;草地生态系统对放牧的响应受放牧强度和年平均降水量的影响,中度放牧有利于维持植物地下部分的生长,轻度放牧有利于维持土壤水分和养分;在年平均降雨量较低(<300 mm)的干旱地区,植物可能具有更好抵抗放牧干扰的能力,放牧对土壤养分的扰动不严重,在年平均降雨量较高(>400 mm)的湿润地区,放牧更容易改变土壤微生物的群落组成。

To clarify the overall influence of grazing on the grassland ecosystem on the Loess Plateau,39 relevant literatures were selected for Meta-analysis to explore the effects of grazing on grassland vegetation,soil physicochemical properties,and soil microorganisms on the Loess Plateau,and further analyzed the relevant factors affecting its grazing effect in this study.The results showed that grazing had no significant effect on grassland plant diversity,soil bacterial abundance,actinomycetes abundance,and total microbial abundance,but significantly reduced grassland productivity and soil carbon,nitrogen,and phosphorus nutrients,and significantly increased soil bulk density,pH,and soil fungal abundance.The response of the grassland ecosystem to grazing was affected by grazing intensity and mean annual precipitation.Moderate grazing is beneficial to maintain the growth of the underground part of plants,and light grazing is beneficial to maintain soil moisture and nutrients.In dry regions with lower mean annual precipitation(<300 mm),plants may have a better ability to resist grazing disturbance,and the destabilization of grazing on soil nutrients is not serious.In moist regions with higher mean annual precipitation(>400 mm),grazing is more likely to alter the community composition of soil microorganisms.