An ecosystem service value assessment of land-use change on Chongming Island, China
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Chongming Island is the world's largest alluvial island. Its coastal wetland and tidal flats provide many important ecological services including buffers against tidal surges and staging areas for migratory birds. Due to its extraordinary resources, scenic qualities, and its proximity to the city of Shanghai 45 km away, the island is also an attractive tourist destination, and it supports important agricultural and fisheries economies. Yet, large-scale land reclamation projects that are severely affecting these ecosystems have been implemented. In this paper, we report an investigation of changes in land use and ecosystem services on Dongtan (East Beach of Chongming Island) between 1990 and 2000. We used three LANDSAT TM and/or ETM data sets to estimate changes in the size of five land-cover/land-use categories, and we also used previously published value coefficients to estimate changes in the value of ecosystem services delivered by each land category. Finally, we ranked the contribution of various ecosystem functions to the overall value of the ecosystem services. We determined that the total value of ecosystem services in Dongtan declined by 62% from $ 316.77 to 120.40 million per year between 1990 and 2000 (totaling $855.26-981.85 million over 10-years). This massive decrease is largely attributable to the 71% loss of wetlands/tidal flats. Our sensitivity analysis suggested that these estimates were relatively robust. We also found that the contribution of water regulation, water supply, waste treatment, and raw materials increased, while the contribution of nutrient cycling, food production, disturbance regulation, recreation, habitat/refugia, and biological control decreased during the 10-year time period. We conclude that future land-use policy formulation should give precedence to the conservation of these ecosystems over uncontrolled reclamation, and that further land reclamation should be based on rigorous environmental impact analyses. 2003 Elsevier Ltd. All rights reserved.