Grass-livestock balance based grassland ecological carrying capability and sustainable strategy in the Yellow River Source National Park, Tibet Plateau, China

The Yellow River Source National Park (YRSP) is one of the most sensitive and fragile ecological regions in the world. The historical intensive grazing and climate change have resulted in ecological degradation that threatens the wildlife and livestock. Exploring the sustainable strategy is urgent for policy makers to meet the demands for wild ungulates and livestock. In our study, the grassland ecological carrying capability (GECC) was assessed based on the updated grass-livestock balance that considered the grass competition from wild ungulates. The balances between grass and livestock, and GECC and grassland pressure index (GPI) in the YRSP were measured through overlay analysis and geostatistic analysis. The results showed that: (1) the ratio of livestock to wild ungulates in the research area was approximately 4.56: 1, in which the proportion of livestock was 81.75% and the actual number of livestock was 33.84 x 10(4) standard sheep units; (2) Under the scenario of minimum grazing utilisation rate, the theoretical grazing capacity and GECC were 37.83 x 10(4) standard sheep units and -0.13, respectively. Under the maximum grazing utilisation rate, the theoretical grazing capacity and GECC were 41.93 x 10(4) standard sheep units and -0.21, respectively. Since GECC in both scenarios were both less than 0, the grassland was considered to be in surplus and the livestock was not overloaded. However, GPI in the two scenarios were 0.87 and 0.79, respectively, both of which exceeded the warning line of 0.70. Based on GECC, we recommend that the sustainable strategy in YRSP is either to increase the supplementary feeding about 6.40 x 10(4) standard sheep units or reduce the grazing livestock by about 3.50 x 10(4) standard sheep units.

Automated summary

The Yellow River Source National Park is a highly sensitive and fragile ecological region due to historical grazing and climate change. Assessment of grassland ecological carrying capability and balance between wild ungulates and livestock in the area showed that while livestock were not overloaded, the grassland faced pressure above the warning line. Recommendations for a sustainable strategy include increasing supplementary feeding or reducing grazing livestock to maintain a balanced ecosystem.