Vegetational succession and climatic variability in the monsoonal margin over the past three millennia as indicated by pollen influx data from Daihai Lake, Inner Mongolia

In recent years, the impact of global warming has received increasing attention, and changes in climatic factors such as temperature and precipitation are certain to affect vegetation succession. To assess the impact of climate change on future vegetation succession more effectively, we need to obtain information from the history of vegetation succession. Here, we present a detailed record of the vegetation coverage in the northern margin of East Asian summer monsoon from 812 BCE to 2011 CE based on a well-dated high-resolution pollen influx record from Daihai Lake. The results showed that there were two different stages of high pollen influx: 812 to 500 BCE, when the forest coverage in the Daihai Lake region was the highest, and 1050 to 1550 CE, when the Daihai Lake region was covered by dense grassland vegetation. In other stages, especially after 1550 CE, the vegetation coverage in the Daihai Lake region was relatively sparse. Then, we compared the pollen influx record of Daihai Lake with proxy climate records from high and low latitudes as well as the solar variability through the last 3000 years. We found that the vegetation coverage in the Daihai Lake area was higher when the climate was cooler and wetter and lower when the climate was warmer and drier. We speculate that the vegetation coverage in the marginal region was substantially controlled by moisture conditions and was related to the hydrographic processes of the surface ocean in the tropical Pacific.