Environmental change in the Late Pleistocene and later Holocene at Wanda site, Soroako, South Sulawesi, Indonesia

This paper reports the pollen analysis of an 8 m core from a mire at 445 m altitude and 2 degreesS latitude on ultramafic soils near the western shore of Lake Matano, South Sulawesi. The area is almost undisturbed by humans a nd the record is believed to cover about 50-75,000 yr B.P., with some break s in the record. A section from 17,000 to around 5500 yr B.P. and the last 1000 years of the record may be missing or disturbed. The results show that montane forest grew around the site continuously through the late Pleistoc ene with a maximum increase in higher altitude taxa from 35,000 to after 17 ,000 yr B.P., the time of glacial maxima elsewhere. Also in this period, in creases in grass and Casuarina indicate possible drier conditions. The Holo cene sections record lower altitude forest with increased taxonomic diversi ty, including secondary species. The results show that vegetation in the re gion has been sensitive to climatic change, the Pleistocene ecology being c onsistent with a temperature change of about 2.5-3.5 degreesC with a phase up to 50% drier than present. The site climate was possibly affected by she lf exposure in the Gulf of Bone due to lower sea levels. However the tropic al forest demonstrates overall long term stability in which changes in domi nance may reflect minor shifts in disturbance and tree longevity. A distinc tive record of fine charcoal occurs throughout the deposit. This shows that the forest has never been continuously fire-free for a very long time. The cause of the fires may be natural as no evidence for human occupation was discerned. (C) 2001 Elsevier Science BY. All rights reserved.