中国西部退化草地对不同类型恢复措施响应的Meta分析

The response of degraded grasslands to different types of restoration measures in western China:A Meta-analysis

草地是陆地生态系统的重要组成部分,退化草地的恢复对于生态系统结构和功能的稳定性具有重要意义。为研究不同类型恢复措施对退化草地的影响,本研究采用Meta分析方法研究了自然恢复、人工辅助和生态工程措施下草地Shannon-Wiener多样性指数、地上生物量、地下生物量以及土壤有机碳的变化特征,同时探讨了恢复措施适宜性随时空变化情况。结果表明:恢复措施对退化草地的影响存在差异,自然恢复显著增加地上和地下生物量,人工辅助显著增加地上和地下生物量,同时会显著减少物种多样性,生态工程对各指标影响均不显著,由此可知,自然恢复的正作用更明显,其适宜性更高。同时,草地恢复是动态变化过程,恢复措施的适宜性随时间变化,适宜性更高的措施在恢复5年以内为人工辅助而在5年以上为自然恢复。此外,正作用更明显的措施在重度、中度和轻度退化草地分别为生态工程、人工辅助以及自然恢复和人工辅助,说明不同草地退化阶段适宜的恢复措施存在差异。最后,恢复措施的适宜性还受空间影响,半湿润、半干旱和干旱地区适宜的恢复措施分别为人工辅助、自然恢复和生态工程。综上所述,对退化草地进行恢复时,需要因时制宜、因地制宜选择恢复措施。

Grasslands are an important component of terrestrial ecosystems.Restoring degraded grasslands is critical for the stability of ecosystem structure and function.The effects of different types of restoration measures on degraded grasslands were examined by meta-analysis.Restoration measures included natural restoration,artificial supplementary,and ecological engineering.This study investigated the effects of various restoration measures on the Shannon-Wiener index,aboveground biomass,underground biomass,and soil organic carbon.The spatial and temporal variability of the effectiveness of restoration measures was determined.The results revealed that the effects of restoration measures on degraded grasslands varied.Natural restoration significantly increased aboveground and underground biomass;artificial supplementary restoration significantly increased above-ground and under-ground biomass but significantly decreased species diversity;and ecological engineering had no significant effect on any of the indices.The positive effects of natural restoration were more evident,and its suitability was higher.Additionally,the suitability of the restoration measures changed over time.Artificial supplementary measures were more effective within five years of restoration,whereas natural restoration was effective after more than five years.Moreover,ecological engineering,artificial supplementary,and natural restoration exhibited positive effects on heavily,moderately,and lightly degraded grasslands,respectively.The suitability of restoration measures was also influenced by spatial characteristics.The restoration measures suitable for semi-humid,semi-arid and arid areas were artificial supplementary,natural restoration,and ecological engineering,respectively.Therefore,grassland restoration measures should be selected according to spatio-temporal characteristics.