A 2000-year environmental history of the Upo Wetland on the Korean Peninsula

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 We used information from historical documents and sediment records to investigate the wetland. A 40-cm sediment core was collected and dated using Pb-210 and C-14. Physical and chemical variables in the core were measured and pollen was analyzed. The environmental 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 characteristics 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 anthropogenic 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.