ORIGINAL PAPER A 2000-year environmental history of the Upo Wetland on the Korean Peninsula Heungtae Kim • Jae Geun Kim Received: 1 May 2009 / Accepted: 24 November 2009 / Published online: 5 December 2009 Ó Springer Science+Business Media B.V. 2009 Abstract The Upo Wetland was designated an internationally important wetland by the Ramsar Convention and is the largest inland wetland on the Korean Peninsula. This study was conducted to reveal the environmental history of the wetland and its surroundings, and to evaluate the influence of human activities on the ecosystem. We used infor- mation from historical documents and sediment records to investigate the wetland. A 40-cm sediment core was collected and dated using 210 Pb and 14 C. Physical and chemical variables in the core were measured and pollen was analyzed. The environmen- tal history of the Upo Wetland over the last 2,000 years was divided into three phases. Seawater may have entered the wetland around 2,000 years ago. Upo was probably a riverine wetland with a floodplain that experienced relatively rapid water flow and erosion until about AD 870. Thereafter, Upo became a palustrine wetland with lacustrine charac- teristics during an unstable environmental phase until some time between 870 and 1880 AD, when water flow decreased and both the water retention time and the area of flooding within the wetland increased. Construction of artificial levees within the wetland during the twentieth century constituted an anthro- pogenic impact superimposed on natural changes, and Upo became a shallow lake. Inputs of nutrients and other pollutants from the catchment continue to threaten the Upo ecosystem despite the establishment of policies intended to protect this important ecosystem. Keywords Embankment Á Eutrophication Á Lacustrine wetland Á Palustrine wetland Á 210 Pb and 14 C dating Á Seawater intrusion Introduction Wetlands perform many economically and ecologi- cally valuable services. They purify water, support biodiversity, prevent floods, and store carbon (Zedler and Kercher 2005). Wetlands in northeast Asia, including those in the Nakdong River Basin in the southeastern part of the Korean Peninsula, are impor- tant habitats for migrating waterbirds (Brinson and Malvarez 2002). In addition to their ecological func- tions, wetlands have high productivity and can be converted into agricultural lands. Therefore, economic development and increases in the human population in the twentieth century have caused conflicts over land use, and freshwater wetlands have disappeared in many areas around the world despite their ecological impor- tance (Foote et al. 1996; Brinson and Malvarez 2002; Byun et al. 2008). Although the Nakdong River Valley originally included many floodplain sys- tems, many small backswamps were converted to H. Kim Á J. G. Kim (&) Department of Biology Education, Seoul National University, Seoul 151-748, Korea e-mail: jaegkim@snu.ac.kr 123 J Paleolimnol (2010) 44:189–202 DOI 10.1007/s10933-009-9396-6