Trade-offs and cost-benefit of ecosystem services of revegetated degraded alpine meadows over time on the Qinghai-Tibetan Plateau

Abstract

A great number of ecological conservation and restoration projects have been implemented to prevent the deterioration of alpine grasslands on the Qinghai-Tibetan Plateau. However, few researches have documented the effects of ecological projects on the improvement of ecosystem services of alpine grasslands based on field investigations. In this study, 24 plots of alpine meadow along different succession times were investigated to estimate the impacts of ecological restoration on four key ecosystem services (i.e., soil organic carbon sequestration (SOCS), soil total nitrogen sequestration (STNS), biodiversity, and aboveground biomass) in the Glog Tibetan Autonomous Prefecture of Qinghai Province, China. The results showed that STNS and biodiversity of degraded alpine meadows were significantly improved through restoration actions, while SOCS and aboveground biomass didn’t change. The relationships of above- and belowground ecosystem services changed over restoration time. Trade-offs between aboveground biomass and biodiversity, between aboveground biomass and SOCS at stage Ⅲ were significantly improved, in contrast to those at stage Ⅰ. Trade-off between STNS and biodiversity at stage Ⅱ was significantly increased, in contrast to those at stage Ⅰ. Economic profit of ecological restoration was insignificantly changed along restoration time. Our results suggested that human-induced restoration was a feasible approach to improve the ecological and economical values of “Black Beach” on the Qinghai-Tibetan Plateau, and further restoration actions and long-term research are required to enhance the ecosystem services of revegetated degraded meadow.