Combining CENTURY model and vulnerability assessment index to estimate aboveground biomass and ecological vulnerability of grassland: An analysis in Northwest Sichuan Plateau

Evaluating the impact of climate change on grassland productivity using grassland ecological models is of great significance for the sustainable use of grasslands. Based on meteorological, soil, and grassland data, this study employed the Grassland Ecosystem Model (CENTURY) to scrutinize the spatiotemporal distribution characteristics of above-ground biomass (AGB) of grasslands in the northwest Sichuan Plateau (NWSP) and established a spatial distribution pattern of grassland vulnerability levels in the NWSP. Utilizing five on-site verification points, the CENTURY model worked well in simulating the AGB of grasslands in the NWSP and was suitable for investigating the impact of climate change on grassland productivity in the NWSP. Simulation outcomes revealed a zonal distribution pattern of the annual average AGB in grasslands across the NWSP, with the central region exhibiting higher levels surpassing 800 g m−². From 1961 to 2020, the AGB of grasslands showed a significant increase trend, with growth rates ranging from 14.2 to 25.9 g m−2·(10a)−1. Overall, the northern and central regions of the NWSP experienced substantial climate impacts, coinciding with a marked increase in biomass. From 1961 to 2020, the overall vulnerability of grasslands in the NWSP was relatively low, with areas exhibiting moderate or lower vulnerability levels accounting for 83.8 %. The overall spatial distribution pattern showed low vulnerability in the north and central regions, and high vulnerability in the eastern and southwestern edges.