Grassland restoration activities improved ecosystem services: A quantitative synthesis via meta-analysis

Grasslands, as the largest terrestrial ecosystem, hold significant ecological and economic value. Due to widespread grassland degradation driven by environmental changes and human activity, restoration efforts have increasingly prioritized improving the health of grassland ecosystems. Ecosystem services serve as a critical metric for evaluating the success of these ecological restoration efforts. However, quantitative evidence remains limited regarding how different restoration measures affect multiple ecosystem service categories and how these effects are regulated by environmental and baseline conditions. In this study, a meta-analysis was conducted to assess the impact of grassland restoration on ecosystem services. The results revealed that combination measures produced the most substantial improvements in ecosystem services, with increases of 94.2 % in total services, 120.1 % in provisioning services, and 102.4 % in regulating services. Natural recovery and reseeding showed stable benefits, with total, provisioning, and regulating services increasing by 50.7 % and 77.7 %, 96.6 % and 152.4 %, and 64.6 % and 101.1 %, respectively. Fertilization demonstrated the least improvement, with total and provisioning services increasing by 35.5 % and 57.4 %, respectively. Supporting services, however, proved difficult to restore, with only natural recovery showing a significant positive effect. Additionally, the effectiveness of ecological restoration measures is influenced by various factors, including time accumulation, precipitation, altitude gradients, and the baseline condition of the ecosystem. The restoration of grassland ecosystem services is a complex, nonlinear process shaped by the interaction of these factors. Therefore, it is crucial to understand the specific environmental background of a given location before selecting the most suitable restoration measures based on the restoration goals. This approach will enhance the effectiveness and sustainability of future restoration efforts.