Late Holocene vegetation, climate, and natural disturbance records from an alpine pond in central Taiwan

Abstract

Paleo-typhoon activity and its correlation with El Nino Southern Oscillation (ENSO) during the late Holocene has been reported by numerous studies, but our understanding of the impacts of typhoons as natural disturbance events on subtropical forest ecosystems remains unclear. In this study, we used a multi-proxy method, including pollen, grain size, and the ratios of Sr/Ti and Rb/Ti from XRF-scanning measurements, on a sediment core from Tunlumei Pond (TLM) to reconstruct vegetation dynamics and the records of natural disturbances, such as heavy rainfalls, earthquakes, or typhoons, in central alpine Taiwan during the past 2400 calibrated years before the present (cal yr BP, where present refers to 1950 AD). The trend in variation between the percentages of upper montane forests and PC1 value indicates that the cold/dry climate changed to a warm/humid climate from 1800 cal yr BP upward, corresponding to the Roman Warm Period. This local change might be corresponded to regional trend and relative to the East Asian summer monsoon fluctuation. Coarse grain particles associated with the transition of the pollen zone indicate frequent and/or strong natural disturbances at 1510 cal yr BP and the impacts of the early Little Ice Age (LIA) during 530-480 cal yr BP. The palaeoecological record of TLM provides very useful information for both decision making and policy planning in present and future subtropical forest management, as well as restoration after a catastrophic event.