Holocene biome reconstruction on the Chinese loess plateau based on pollen

Reconstruction of past vegetation changes is critical for sustainable development in the fragile and highly eroded ecosystems on the Chinese Loess Plateau (CLP) under global change, particularly in light of future warming events. In this study, we collected fossil pollen data from 40 sites to reconstruct the Holocene (since 11 ka) vegetation pattern of the CLP using the biomization method. The results demonstrate that the CLP vegetation during the entire Holocene was dominated by grassland landscapes in most areas and periods, whereas the forest landscape only developed in some areas during certain periods. Steppe vegetation rather than forest vegetation was distributed in the central region of the CLP. Six forest biomes were primarily distributed in the southwestern and northeastern plateau high-altitude areas, showing notable expansion toward low latitudes and longitudes during the early to mid-Holocene. The steppe biome showed a rather wide distribution, primarily in the center and south, and especially in the expanded western region during the Early Holocene. Minor variations were observed for the widely distributed steppe biomes that shifted to high longitudes and latitudes during the Holocene. The desert biome was identified in the relatively restricted western and northern regions of China. Reconstructed biome spatial distributions showed a large vegetation gradient on the CLP. This suggests that variations in forest biomes on the CLP were potentially influenced by changes in precipitation. Different topographies within the same area led to different biomes. In addition, increased human activity may cause vegetation destruction.