Holocene human activities recorded by pollen in the Mu Us Sandy Land in north-central China

Explaining the regional peculiarities of human activities in different phases of the Holocene is crucial for a better understanding of the development of the natural environment and of potential past, present, and future human-land relationships. However, Holocene human activity records, especially anthropogenic pollen indicators, are still rare. Here, we reconstructed a human influence index (HII) for the Holocene in the Mu Us Sandy Land utilizing a pollen-based random forest model. Nine human-related species were identified based on the analysis of the main pollen species, HII, mean annual temperature, and annual precipitation. The substantial increase in the reconstructed HII and the percentage of human-related pollen indicated a significant increase in the intensity of human activity since 5.0 ka BP. During the period of 7.0–5.0 ka BP, agriculture was the main lifestyle for humans, while a mix of agricultural and pastoral activities occurred after 5.0 ka BP. In addition, by combining human activities and climate proxies, we found that the intensity of human activity was controlled by climate change, and the impact of climate change on human activity intensity gradually decreased since 2.8 ka BP. Our results may provide a significant reference for understanding the process of human adaptation to natural variation and for sustainable ecological development.