Inhabitants near Poyang Lake, in the Central Yangtze River Basin, China, are
vulnerable to loss of life and livelihood because of the interactions of flooding and land-use policies and decisions. We analyzed implications of land-cover patterns for vulnerability to flooding in the Poyang LakeRegion. Land-cover and change were mapped using multitemporal Landsat TM/ETMϩ images at high and low water levels from 1987, 1993, 1999, and 2004
IntroductionTo support China's population, which grew from 540 million in 1949 to 1.3 billion in 2006, agricultural self-sufficiency, especially in grain production, has been one of the central goals of the Chinese government. Because of a limited area of farmland per capita and inefficient farming methods historically, the primary means of increasing the total amount of agricultural yield has been to enlarge the farmland area. One consequence of this has been the conversion of large areas of natural wetlands in fertile areas, such as those in the Central Yangtze Basin, to farmland (wetland reclamation). During the past twentieth century, many levees were built to encircle new farmland in low elevation areas adjacent to lakes and rivers, forming polders that are protected against flooding (Zhao et al., 2003 Chinese government declared that agricultural grain selfsufficiency had been reached and certain land-use policies were reconsidered (Rozelle et al., 1997). Beginning in 1986, wetland reclamation was banned, and laws have promoted restoring some reclaimed farmland back to natural wetland (wetland restoration). In addition to the policies and laws regulating the conversion of wetlands and farmlands, grain markets have also had an impact on land-use. Beginning in the early 1990's, China has transitioned from a planned economy, where grain prices were fixed by the government, to a market economy, where prices have been determined mainly by the grain market. Grain prices increased gradually in the period from 1980 to 1993, very rapidly from 1993 to 1997, and then decreased between 1997 (Statistics Bureau of Jiangxi Province, 2004. In response to the recent decrease, the central government exempted farmers from agricultural taxes in 2004 to encourage farmers' activity in grain production (Gale, 2005). In the transitioning economy, the trend has also been toward greater and more rapid economic growth and urbanization, including rural farming and wetland areas. Over time, intense land-use and human settlement in the floodplains of the Central Yangtze Basin have exposed millions of people to flooding hazards in that region. We used the distribution and changes of natural (e.g., wetlands and water) and human-managed land covers (e.g., urban and agriculture) over an approximate 20-year period to evaluate the vulnerability of a population and how it has changed as a result of these recent policy and economic changes.The Poyang Lake Region (PLR) in the Central Yangtze River Basin in Jiangxi Province is an important regional example of such interactions between government policies...