Continuous Decrease in Grassland Quality in Cold-Season Pasture over Three River Headwater Region

Alpine grasslands in the Three River Headwater (TRH) region have suffered serious degradation owing to global climate change and human activity. Fencing is a major countermeasure implemented in the TRH region by the Ecological Protection and Restoration Program (EPRP) launched by the Chinese government. Fencing from the EPRP was to guarantee prohibited grazing during the growing season and rotation grazing during the cold season in the cold-season pasture. However, fencing excluded grazing over the entire growing season in previous studies, which was quite different from the EPRP. Thus, the protective effect of fencing from the EPRP in the TRH region cannot be confirmed based on previous studies. This study presents trends in vegetative and reproductive branch heights, vegetation cover, and aboveground biomass from 2005 to 2017, using ordinary least squares regression based on field observation data from 39 fenced sites from the EPRP in the TRH region. The results indicated that vegetative branch height, reproductive branch height, and vegetation cover decreased significantly by 34.8%, 38.2%, and 5.4%, respectively, over the study period ( P < 0.05). The biomass proportion of Gramineae and Cyperaceae decreased by 48.2% and 23.9%, respectively ( P < 0.05), whereas those of poisonous weeds and edible forbs increased by 170.3% and 42.0% ( P < 0.10), respectively. This indicated a decrease in grassland quality at the fenced sites from the EPRP. The decrease in grassland quality may have been mainly caused by severe livestock overloading during the cold season. A competitive edge from forbs and poisonous weeds under fencing in degraded alpine grasslands may have further exacerbated grassland degradation. These results suggest that fencing in cold-season pasture from the EPRP did not achieve the objective of restoring grasslands under severe livestock overloading in the TRH region over the study period. These findings provide a significant basis for improving ecological protection and restoration policies in the TRH region. (c) 2025 The Authors. Published by Elsevier Inc. on behalf of The Society for Range Management. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)