人类的不合理利用造成我国典型草原的严重退化，危害区域的可持续发展。自然草地的研究已发现植物-土壤反馈对植物群落的构建和演替、物种多样性的维持及生态系统功能起着关键作用。然而在典型草原退化过程中植物-土壤反馈如何驱动植物群落的动态变化及作用机制尚不清楚。本项目以典型草原退化过程中早期、中期、晚期的优势物种为研究对象，从个体和群落两个尺度上系统研究植物-土壤反馈对草地退化演替的影响及作用机制。在个体尺度，阐明植物-土壤反馈对个体动态生长的影响及作用的关键生长时期；在群落尺度，明确植物-土壤反馈对种间竞争和群落动态的影响；最后通过对关键根系性状和土壤特性的定量分析，并结合结构方程模型，揭示植物-土壤反馈影响植被退化演替的作用机理。本研究既能深化对草地退化过程中植被演替驱动机制的理解，同时也可以为区域生态系统的保护和恢复提供理论依据。

Unreasonable human disturbance leads to severe degradation of steppe grassland, which threatens regional sustainable development. Plant-soil feedback plays a key role in plant community composition and succession, biodiversity maintenance and ecosystem services in natural grasslands. However, it remains unclear how plant-soil feedback steers plant community dynamics and the underlying mechanisms on degradation succession of steppe grassland. This project will systematically study the effects and unravel the underlying mechanisms of plant-soil feedback on degradation succession of steppe grassland at individual and community levels. Specifically, we will first study the effect of plant-soil feedback on individual plant growth during plant life stage and identify the key growth stage. Then, we will investigate how plant-soil feedback alters the severity of interspecific competition and community dynamics. We further unravel the underlying mechanisms through quantifying the root traits and soil properties and analyzing their relationships with the structural equation modeling. This project will deepen the understanding of the driving factors affecting vegetation succession during grassland degradation and provide scientific evidence and foundation for conservation and restoration of regional ecosystems.