Reconstruction of an 8,000-year environmental history on pollen records from lake buyan, central bali

Abstract

New evidence from Lake Buyan, a 65-m-deep caldera lake in central Bali, presents an 8,000-year record of vegetation and climate change through palynological and physio-geochemical analyses. The distinct sediment phases associated with relative vegetation fluctuations and change of physio-geochemical index suggest that Bali might have experienced cycles of wet and dry climate change over 8,000 years. Vegetation composed of marshland/gap-colonizers, being coeval with the intensive process of erosion as indicated by an increased input of minerogenic material from the catchment, characterizes the periods when homogeneous lake mud sediments are formed, indicating relatively higher rainfall at period of 8.0–6.6 ka BP, 5.1–3.6 ka BP and 2.8 ka BP to present. At the time when laminated lake sediments commence, e.g., 6.6–5.1 ka BP and 3.6–2.8 ka BP, vegetation of a rather dry and fire-resistant character dominates, in concomitant with lower input of minerogenic material and suggests drier episodes. Regional comparison indicates that human-induced vegetation destruction is insignificant in Bali, except that cultivation activities might have been manifested in the recent 3,000 years, and the climatic variability observed from this core was probably El Niño Southern Oscillation (ENSO)-related.