As a climate-sensitive critical ecological function area, alpine grassland ecosystems on the Qinghai-Xizang Plateau (QXP) are highly vulnerable to global warming. This study aims to predict the spatiotemporal dynamics of aboveground biomass (AGB) for plant functional groups under future climate scenarios. To assess the response of the AGB to global warming on the QXP, four methods (random forest, multivariate adaptive regression, enhanced regression trees and support vector machine) were employed to evaluate alpine grassland conditions for both the recent past (2018–2021) and the projected future (2021–2100) base on 337 field observations of AGB. The results indicated that from 2018–2021, the average AGB of grassland was 91.80 g/m 2 , with the AGB that supports grazing being 60.39 g/m 2 . Specifically, the AGB values for grasses, sedges, legumes, and forbs were 26.03 g/m 2 , 20.80 g/m 2 , 4.28 g/m 2 , and 40.70 g/m 2 , respectively. The grassland AGB tended to decrease across all the time periods under all the future scenarios, except for SSP5-8.5 during 2060–2080. However, the AGB that supports grazing was projected to increase during the periods 2040–2060, 2060–2080 and 2080–2100 under all future scenarios. With respect to the different plant functional groups, the AGB of the grasslands increased across all the scenarios, whereas the AGB of the sedges, legumes, and forbs decreased in all the situations. In this study, we introduce a novel perspective in which changes in grassland AGB and grazing carrying capacity are not perfectly synchronized under future SSP climate scenarios.
Wan et al. (Fri,) studied this question.