Late Holocene multi-proxy records of environmental change on the South Atlantic island Tristan da Cunha Karl Ljung ⁎ , Svante Björck, Dan Hammarlund, Lena Barnekow GeoBiosphere Science Centre, Quaternary Sciences, Lund University, Sölveg. 12, SE-223 62 Lund, Sweden Received 20 November 2005; received in revised form 19 April 2006; accepted 7 May 2006 Abstract Sediment stratigraphies from three sites, one lake, one overgrown lake, and an exposed section, on the island Tristan da Cunha in the temperate South Atlantic were analysed by means of pollen analysis, total carbon, nitrogen and sulphur content determination, magnetic susceptibility measurements and detailed radiocarbon dating. The aim of these studies was to reconstruct the late Holocene vegetation and climatic variations. The oldest sediment sequence extends back to 2300 cal. years BP. The vegetation was relatively stable up to the arrival of humans in the 17th century. The appearance of the introduced taxon Rumex acetosa/acetosella at c. 300 cal. years BP and a subsequent decline in forest cover on the lowland plain provide evidence of substantial human influence on the vegetation well before the establishment of the first permanent settlement in the 19th century. Before the first anthropogenic influence centennial- scale fluctuations in the proxy records are interpreted as reflections of local hydrological changes, probably caused by variations in precipitation. As inferred mainly from changing proportions of pollen derived from telmatic and terrestrial taxa and corresponding changes in the deposition of mineral matter by fluvial erosion, lake levels were low between c. 1450 and 1050 cal. years BP, and high between c. 1050 and 300 cal. years BP. These variations coincide with known climatic changes in Southern Africa and in the North Atlantic, suggesting that the inferred hydrological changes on Tristan da Cunha were related to large-scale variations in the general oceanic and atmospheric circulation in the Atlantic region. © 2006 Elsevier B.V. All rights reserved. Keywords: Late Holocene; Pollen analysis; Vegetation history; Hydrological changes; Tristan da Cunha; South Atlantic Ocean 1. Introduction The South Atlantic circulation plays an important role in the global climate system and is coupled to the climate of the bordering continents and the North At- lantic region (e.g. Wefer et al., 2003). However, studies of Holocene environmental change in the South Atlantic are hampered by the lack of suitable terrestrial archives. Islands are few and many are situated in areas dominated by permanent high-pressure cells with low precipitation, and few archives such as peat or lacustrine sequences occur. The stratigraphic resolution of most marine sediment cores obtained from the South Atlantic Ocean outside the diatom ooze belt is often too low to portray detailed information about Holocene changes below the centennial scale (e.g. Nielsen et al., 2004). In this study results from three sites, two sediment cores from crater lakes and one sediment section exposed by fluvial erosion, on the island Tristan da Cunha in the central South Atlantic are presented. The aim is to reconstruct the local environmental history of Palaeogeography, Palaeoclimatology, Palaeoecology 241 (2006) 539 – 560 www.elsevier.com/locate/palaeo ⁎ Corresponding author. Tel.: +46 46 2227888; fax: +46 46 2224830. E-mail address: Karl.Ljung@geol.lu.se (K. Ljung). 0031-0182/$ - see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.palaeo.2006.05.007