Benefits, potential and risks of China's grassland ecosystem conservation and restoration.

Severe threats from ongoing degradation undermine the grasslands to support ecosystem services, biodiversity, and human well-being. Unfortunately, grasslands are often underappreciated and ignored in sustainable development agendas. Despite a series of projects for Grassland Ecosystem Conservation and Restoration (GECR) been implemented in China, the effects and cost-effectiveness of these efforts remain uncertain and untested. Therefore, we developed an integrated assessment framework to evaluate the benefits of GECR, considering ecological value accounting and input-output efficiency estimation. Additionally, we projected potential and risk areas for GECR in the future. The results showed that in 2020, the annual ecological value of China's grassland ecosystem was CNY 246 trillion. The investment in GECR exceeded CNY 7 billion, leading to an ecological benefit of CNY 3478 billion, with an input-output ratio of 1:446. Over the past 20 years, GECR positively impacted nearly 90 % of China's grassland. Furthermore, grasslands in southern provinces with favorable hydrothermal conditions exhibited significantly higher GECR efficiency, boasting an input-output ratio of >1:2000. The arid and semi-arid northern grasslands and the alpine grasslands on the Tibetan Plateau, despite being the main regions for animal husbandry development and GECR, exhibited comparatively lower efficiency and input-output ratio in GECR. Moreover, the central and northwest parts of Tibet showed higher potential and lower risk, indicating their greatest likelihood of benefiting from GECR in the future. Meanwhile, Hulunbeier and Inner Mongolia deserve more special attention to reverse degradation and mitigate climate change due to their lower potential and higher risks. Our study provides an important basis for prioritizing and implementing effective and sustainable GECR treatment methods.