Active restoration of extremely degraded grasslands on the Qinghai–Tibetan Plateau: a review

Approximately 11 million hectares, or 8% of the grasslands on the Qinghai–Tibetan Plateau (QTP), are extremely degraded, posing serious threats to biodiversity conservation, livestock production, and soil erosion. Under the cold, hypoxic environment of the QTP, passive restoration of the degraded grasslands is extremely slow. To accelerate recovery, active restoration, primarily by sowing seeds of native grasses, has been adopted; however, the effectiveness and cost of active restoration remain uncertain. This paper reviews over 100 peer-reviewed publications, and provides a comprehensive analysis of the methods and outcomes of active restoration of extremely degraded QTP grasslands. In general, current restoration efforts have positive impacts on degraded grasslands of the QTP, mainly by increasing soil nutrients, soil seed-bank resilience, vegetation cover, and forage productivity, and by reducing soil erosion. However, detrimental effects such as soil nutrient imbalance, acidification, and vegetation homogenisation have also emerged. Given the critical role of these grasslands in cold-season livestock production, it is essential to develop long-term grassland management strategies administered by local governments and herders. Effective restoration on the QTP should be viewed as a phased continuum, in which interventions are adjusted to shifting recovery constraints and long-term management is needed to balance ecological recovery with the sustained use of grasslands as cold-season pastures. Such an approach would enhance the sustainable resilience of QTP grassland ecosystems.