Evolution of the relative abundance of C 4 plants on the Chinese Loess Plateau since the Last Glacial Maximum and its implications

Understanding the distribution of C 3 and C 4 plants and its forcing mechanisms since the Last Glacial Maximum (LGM) is important for anticipating their possible response to future climate change. The spatiotemporal pattern of C 4 plant abundance on the Chinese Loess Plateau (CLP) is complex and the dominant causal factors are contentious. Here, we use δ 13 C records of organic matter in paleosols from the CLP to reconstruct changes in the representation of C 4 plants since the LGM. The results indicate that the relative abundance of C 4 plants increased after the LGM, reaching a maximum during 10–6 ka bp, and then decreased. Spatially, the representation of C 4 plants was characterized by increasing values from north‐west to south‐east. In addition, the smallest spatial difference (∼10%) in the representation of C 4 plants between the north‐west and south‐east parts of the CLP was during the LGM, and the largest difference (∼30%) was during the early Holocene. We combined our findings with output from the BIOME4 model to study the sensitivity of C 4 plants to changes in climate and atmospheric CO 2 concentration. The results suggest that increasing temperature was the dominant factor driving C 4 plant expansion on the CLP since the LGM.