Mid-late Holocene peatland vegetation and hydrological variations in Northeast Asia and their responses to solar and ENSO activity

Abstract

Peatlands are common components of the Northeast Asian landscapes, while the vegetation and hydrological variations of these peatlands remain unclear. To address this issue, here we use plant macrofossil and grain size analyses to reconstruct the regional vegetation and hydrology dynamics of the Hani peatland over the past ~7766 years. From 7766 cal. yr BP to 6000 cal. yr BP, the Hani peatland was characterized by wet conditions and high water levels. The vegetation community was mainly composed of hygrophilic plants during this period. These features were probably controlled by the high total solar irradiation (TSI) and less El Niño–Southern Oscillation (ENSO) activities. From 6000 cal. yr BP to 2000 cal. yr BP, the Hani peatland was characterized by moderate moisture conditions and decreasing water levels, with the vegetation community dominated by both hygrophilic and xerophilic plants. These features were probably influenced by the decreased TSI and increased ENSO activities. From 2000 cal. yr BP to the present, the Hani peatland was characterized by dry conditions and low water levels composed mainly of xerophilic plants. These features were linked to low TSI and more ENSO activities. These correlations reveal that the millennial scale changes of the peatlands in Northeast Asia were primarily driven by the collective impacts of solar irradiation and ENSO activity, thus expanding our understanding of long term interactions between vegetation, hydrology, and climate of Northeast Asian peatlands.