Grassland ecosystem service value in the Tibetan Plateau has not recovered during 1995–2015

Grasslands in the Tibetan Plateau (TP) provide substantial ecosystem services (ESs) but face considerable challenges. Previous assessments of grassland ecosystem service value (GESV) have revealed substantial uncertainties due to inconsistencies in GES classifications, land use data, and assessment methods. Here, we propose a new classification system, present merged land use data, and develop integrated comprehensive assessment methods to reassess the GESV in the TP from 1995 to 2015, and then analyzed spatiotemporal changes and driving factors. Our findings indicate that: 1) grasslands dominate the TP, covering approximately 70% of the land surface, but have been continuously declining, especially during 1995–2000. 2) The value equivalent factor method tends to overestimate GESV, and our reassessment further emphasized the critical role of grasslands. 3) Temporally, GESV exhibited a measured recovery post-2000, though it remained below initial levels. 4) Spatially, GESV declined from southeast to northwest, mainly influenced by precipitation, although this spatial gradient has gradually diminished. 5) Both climatic and anthropogenic factors significantly influenced changes in GESV, but even dual factors had limited explanatory power. Our reassessment sheds light on the spatiotemporal changes and drivers of GESV in the TP over two decades, which is important for grassland management in the region. However, methodological limitations remain, particularly with regard to data accuracy; and further exploration of spatial heterogeneity and multi-factor interactions are also required.