Quantitative vegetation reconstruction in the Central North China Plain of the last 3000 years based on the REVEALS model

Abstract

The North China Plain is a region where the natural vegetation was increasingly influenced by human activities from ∼3000 cal yr B.P. (Zhang et al., 2017; Peng, 2019). We used pollen, charcoal and sediments from the Dacaozhuang Holocene profile in Ningjinpo, central North China Plain, in combination estimates of relative pollen productivity, to quantitatively reconstruct vegetation changes over the last 3000 years using the REVEALS model. Our aims were to study the combined effects of climate change and human activities on the zonal vegetation. The principal findings are as follows. 1) During 3000–2600 cal yr B.P., the study area was strongly influenced by the Yellow River, leading to a complex pollen source area, which is inappropriate for REVEALS models. Since 2600 cal yr B.P., the sediments were mainly supplied by rivers originating in the Taihang Mountains, and the reconstructed tree coverage was generally less than 20%, while that of herbaceous plants such as Artemisia, Poaceae and Asteraceae was more than 50%. This indicates that the study area was predominantly grassland with trees sparsely distributed in the mountains. 2) Crop plants (Poaceae≥35 μm, and Fagopyrum), and the occurrence of synanthropic plants like Brassicaceae and Urtica/Humulus, together with a high sedimentary content of coarse charcoal particles (>100 μm), indicate substantial disturbance of the natural vegetation by human activities from 2600 cal yr B.P. 3) During the Medieval Warm Period (1300–600 cal yr B.P.), the concentration of charcoal and the proportion of synanthropic plants were relatively high, indicating strong human activity. Nevertheless, the proportion of trees, dominated by Pinus and Quercus, was substantially higher (increasing to more than 19%) compared with the previous interval, indicating an increase in forest vegetation and thus a strong climatic influence on the vegetation. 4) During the periods of the Ming and Qing Dynasties (after 500 cal yr B.P.), the concentration of charcoal and crop plants reached a maximum and the tree coverage decreased substantially (to 4.8%), indicating the highest level of human influence on the vegetation. The shift to a cool and dry climate may also have contributed to the reduction of trees within the landscape.