Montane peat bog records of vegetation, climate, and human impacts in Fujian Province, China, over the last 1330 years

Abstract

We used pollen and grain-size data from a peat bog in Xiansan, Fujian Province, southeastern China, to reconstruct a high-resolution record of vegetation change, climatic dynamics, and human impact over the last 1330 cal BP. During 1330–1200 cal BP, we infer the existence of a swamp bog with dense cypress forests, based on dominant Cupressaceae pollen, suggesting cold and dry conditions during this early period. Fine-grained sediment and higher percentages of wetland pollen and fern spores suggest intermittent-lake conditions, indicating a wet Medieval Warm Period (MWP; 1200–730 cal BP). The increase in coniferous forest and montane shrub-meadow pollen indicate a cold and dry climate during the early to mid-Little Ice Age (LIA; 730–370 cal BP), but coarse-grained sediments associated with more abundant wetland taxa pollen indicate a shallower intermittent-lake landscape, reflecting relatively humid periods during 620–560 cal BP and 400–450 cal BP. During the last 370 cal BP, a rapid increase in the secondary forest component and a gradual decrease in the pollen-inferred floristic diversity index suggest that the natural vegetation was converted to secondary vegetation, as a result of severe anthropogenic disturbance in the montane region of Fujian Province. The reconstructed regional precipitation trend prior to this period was mainly correlated with East Asian summer monsoon (EASM) intensity, which is related to variation in solar irradiation.