Close-to-nature restoration of degraded alpine grasslands: Theoretical basis and technical approach

The alpine grasslands on the Tibetan Plateau, which account for about 40% of the total grassland area in China, serve as an important ecological barrier to protect China’s water resources and for ecological security. Although the vegetation activity of alpine grasslands on the Tibetan Plateau has been overall improving during the past decades, most of the grasslands are still suffering from varying degrees of degradation, with some part even deteriorating. In the present protection and construction of ecological barriers on the Tibetan Plateau, the restoration of the degraded alpine grasslands through current technical approaches often end up with low stability and sustainability, and the ecosystem multifunctionality and multiserviceability of the grasslands are often difficult to be fully recovered. This is mainly because the present approaches rarely draw support from the natural restoration processes, along with the technical limitations of optimizing the assembly and supplementary sowing with appropriate native grass species that are often rare, and of improving soil quality using microbial fertilizer and nutrients. Therefore, it is urgent to develop an effective and sustainable restoration approach of the degraded alpine grasslands. The primary tasks of close-to-nature restoration with ecological conservation as its premise focuses on maintaining biodiversity and enhancing ecosystem multifunctionality and multiserviceability. Close-to-nature restoration adopts traditional artificial restoration approaches and relies on natural ecological processes to achieve sustainable ecological restoration. It focuses on “based on nature” and “return to nature”, and realizes sustainable restoration through the self-regulating function of natural ecosystem. Therefore, ecosystems that are restored through close-to-nature restoration may maintain higher biodiversity, provide more ecosystem functions and services, and increase resilience to natural disasters. This paper proposes to apply the close-to-nature restoration to recover degraded alpine grasslands on the Tibetan Plateau, and addresses why it is a natural choice on the basis of ecological theories with respect to biodiversity and the multi-functionality and multiserviceability of ecosystems, as well as the uniqueness of alpine grasslands on the Tibetan Plateau. Based on this, this paper further proposes that seed multiplication, and assembly and supplementary sowing technology of native grassland species are the bottlenecks to the close-to-nature restoration of alpine grasslands, and that the combination of soil nutrients and microbial regulation is an essential supplementary measure. This study, which integrates the theory of close-to-nature restoration and the corresponding techniques, hopefully can provide a nature-based solution for the restoration of the degraded alpine grassland ecosystems on the Tibetan Plateau.