Climate resource utilization rate and livestock-carrying capacity of grasslands in the Three River Headwaters region over the past 40 years

The scientific evaluation of the climate resource utilization rate and livestock-carrying capacity of grasslands in the Three-River Headwaters region (TRHR) is the basis for effective resource utilization and ecological protection. This is of great significance to the sustainable development of grassland animal husbandry and the construction of a regional ecological civilization. The Three-River-source National Park, located in the ecologically fragile and sensitive alpine region of the Qinghai Tibet Plateau, is an important biodiversity protection area for Tibetan antelopes. The traditional utilization area outside the Three-River-source National Park is an important support area for local herders in the maintenance of their livelihood. Using the GLOPEM-CEVSA model, this study simulated the actual grassland yield (GY_A) and climate grassland yield (GY_C) in the TRHR from 1981 to 2018, calculated the corresponding theoretical livestock-carrying capacity (CL) of the grassland, and evaluated the climate resource utilization rate (C) and theoretical livestock-carrying capacity of grasslands. The results showed that the average GY_A and GY_C were 852.56 and 1 357.14 kg·ha⁻¹, respectively; the average climate resource utilization rate (GY_A/GY_C) of grassland in the TRHR was 62.82%; and the spatial distribution presents an increasing trend from the southeast to the northwest. The average climate resource utilization rate of the three parks in the Three-River-source National Park was 61.92%～66.42%. In addition to the Three-River-source National Park and Tanggula Township, with a high utilization rate of climate resources, the eastern and southern counties still had approximately 35% climate potential, that is, 505.53 kg·ha⁻¹ grassland yield potential and 0.44 SU·ha⁻¹ livestock carrying potential. Therefore, it is suggested to make full use of climate resources and develop grassland animal husbandry in areas with good hydrothermal conditions in the eastern and southern regions of the TRHR; improve the climate resource utilization rate and productivity of grasslands; undertake and share the pressure of animal husbandry production in the Three-River-source National Park, so as to protect the fragile ecosystem and biodiversity of the park; and promote the stable and sustainable development of herdsmen’s livelihood, animal husbandry production, and ecosystem in the TRHR.