Grasslands are the most critical ecosystem on the Qinghai-Tibet Plateau. Their effective protection and restoration are vital for maintaining regional environmental stability and ensuring national ecological security. However, intensified global climate change and increasing human activity have significantly impacted the fragile grassland ecosystems of the headwater region of the Yangtze River, leading to severe degradation. This study integrates data from literature reviews, field surveys in representative areas, and stakeholder questionnaires. It aims to identify grassland degradation patterns, evaluate the characteristics and effectiveness of current ecological restoration technologies, and assess regional demand for ecological solutions. Key findings include: (1) Four distinct types of grassland degradation were identified, primarily driven by natural factors (e.g., climate change, rodent infestation) and human activities (e.g., overgrazing, livestock overloading). (2) Ecological technologies applied across the four degraded areas were assessed across five dimensions: application difficulty, promotion potential, maturity, suitability, and benefits. A deviation degree score quantified technology performance and restoration effectiveness. Fencing and enclosure, ecological compensation, and species selection emerged as the most effective technologies. Ecological migration and artificial rodent control faced significant implementation challenges. (3) Based on implementation outcomes, the study identifies current challenges and future requirements for ecological technologies tailored to specific degraded areas. This research provides valuable case studies for addressing grassland degradation in fragile ecosystems and offers a scientific basis for advancing sustainable grassland use and enhancing regional ecological carrying capacity.

The “Yarlung Zangbo River, Lhasa River and Nyangqu River” (YLN) region is the main grain producing area on which the Tibetan people depend for survival. The densities of soil organic carbon (SOC), total nitrogen (TN) and total phosphorus (TP) in farmlands are closely related to grain production. Scientific management and regulation of these nutrient densities are of great significance for ensuring food security. However, accurate simulations of spatial variations in the densities of SOC (SOCD), TN (TND) and TP (TPD) and the spatial distributions of SOCD, TND and TPD are still unclear. In this study, 388 samples of cultivated soils at 0-10 and 10-20 cm in the YLN region were collected to determine the SOC, TN, and TP contents, as well as pH and bulk density (BD). Random forest models of SOCD, TND and TPD were constructed using longitude, latitude, elevation, mean annual temperature, mean annual precipitation, mean annual radiation and vegetation index, which were then used to obtain the spatial distribution maps of SOCD, TND and TPD, and the storages of SOC (SOCS), TN (TNS) and TP (TPS). Mean annual radiation can partially explain the spatial variations of SOCD and TND, in addition to temperature and precipitation. The relative biases between modelled and observed SOCD, TND, TPD, SOCS, TNS and TPS ranged from -9.43% to 7.57%. The SOCD and TND increased from west to east, but they were both low in the middle and high in the north and south. The SOCD and TND decreased with increasing pH and BD. SOCD, TND and TPD were low at mid-elevations but high at low and high elevations. The SOCD, TND, TPD, SOCS, TNS and TPS were 2.72 kg m^-2, 0.30 kg m^-2, 0.18 kg m^-2, 4.88 Tg, 0.54 Tg and 0.32 Tg, respectively, at 0-20 cm over the cultivated lands of the YLN region. Based on these results, the random forest models constructed in this study can be used for subsequent related studies. Besides warming and precipitation changes, radiation changes can also affect SOCD and TND. In terms of the production of food crops such as highland barley, the farmland soils in the YLN region currently can have relative deficiencies of nitrogen and phosphorus nutrients. In the future, measures such as increasing the application of organic fertilizers should be taken to improve the carbon sequestration capacity and nitrogen and phosphorus nutrition of the soil. These findings have important guiding significance for the fertilization management of cultivated lands in the YLN region and other alpine regions similar to the YLN region.

Few studies have categorically analyzed the factors governing soil erosion spatial layout formation and changes within it from a static or dynamic perspective. In this study, we explored the factors influencing soil erosion changes in Liangshan Prefecture, Sichuan Province. The Revised Universal Soil Loss Equation model was used to calculate and grade the soil erosion modulus in the study area from 1990 to 2023 and analyze its spatiotemporal variations. Geographical detectors were introduced to determine the factors influencing erosion layout, inception, and development. From 1990 to 2023, soil erosion in Liangshan Prefecture was moderately low. Areas with high soil erosion grades were mainly distributed in the Niri, Meigu, and Zhaojue river basins, characterized by low vegetation coverage and high topographic fluctuation, and along the Jinsha River, which is greatly affected by industrial development. Land use type was the most critical factor affecting the spatial layout of the soil erosion intensity. Precipitation (55.28%) was the dominant factor governing the change in soil erosion intensity distribution. This study revealed the dynamic changes and driving factors of soil erosion in the past 30 years in Liangshan and suggests erosion prevention measures that can be used for regional soil erosion control.