Soc Changes Were More Sensitive in Alpine Grasslands Than in Temperate Grasslands During Grassland Transformation in China: A Meta-Analysis

Abstract

[Abstract] The effect of grassland utilization and management changes (grassland transformations) may change soil carbon storage even to carbon emission. Grassland types may present a greater contribution to changes in soil carbon storage during grassland utilization and management changes, however, few studies focused on effects of grassland types on changes in soil organic carbon (SOC) stocks during grassland transformations. Here, a comprehensive meta-analysis was conducted to explore the effects of grassland transformation on SOC stocks among grassland types based on 325 peer-reviewed studies over China. The results showed that SOC changes were more sensitive in alpine grasslands than in temperate grasslands during grassland transformation. Especially in the C loss process, the SOC loss rates (Rs) of alpine grasslands were 3.3 and 7.3 times that of temperate grasslands on 1–5 and 6–10 years, respectively. Additionally, the higher SOC stock was the major factor of the SOC loss of alpine grasslands, and the initial SOC stock of alpine grasslands was about 3 times that of temperate grasslands. The low-temperature environmental conditions may limit the carbon decomposition and emission in alpine grasslands, but excessive disturbance will destroy the protective effect of low temperature. Therefore, the results proposed that soils of alpine grasslands in high-altitude areas have a large carbon sink potential but are also vulnerable and more attention should be paid to alpine grasslands relative to temperate grasslands. The future plan should be focused on maintaining of the low-temperature habitat and protecting of the existing soil carbon storage in alpine grasslands, and improving soil carbon sink capacity in temperate grasslands, because improving soil carbon sink capacity during sustainable utilization of grassland ecosystem is of great significance for coping with future reducing carbon emission.