Impacts of the Sloping Land Conversion Program on the Land Use/Cover Change in the Loess Plateau: A Case Study in Ansai County of Shaanxi Province, China
2011, 26 (11):
Induced by population pressure, economic growth, and historic exploitation, a large portion of China’s primary forests and wetland was depleted, and a high percentage of its farmland and grassland was degraded. These ecosystem disturbances caused extensive desertification, flooding, soil erosion, dust storms, elevated levels of greenhouse gas emissions, and severe damage to wildlife habitat. In order to address devastating environmental crises and improve human well-being, China has been undertaking several major ecological restoration efforts, of which the Sloping Land Conversion Program (SLCP) (also called Grain for Green Project) is the largest land retirement/reforestation program in the developing world, which can alter the land use/cover pattern in a considerably short time period. Here, we characterized the impacts of the SLCP on the land use/cover pattern and their consequences in Ansai County on the Loess Plateau, China, by using Landsat MSS/TM/ETM+images of six periods of 1978, 1990, 1995, 1999, 2006 and 2010. Land use/cover information was obtained using satellite remote sensing techniques. Then the impacts of SLCP on the land use/cover pattern were analyzed by the statistical models. Grassland, cultivated land and woodland were the three dominant land cover categories of the study area, and the land use/cover change was generally in unbalanced status dominated by one-way transition. In the whole research period, cultivated land declined substantially after a small increase, with an overall decreasing rate of 38.4%, woodland decreased first then followed by an increase, with an overall increasing rate of 4.36%, and shrubs together with grasslands decrease while the built-up area increased continuously. SLCP accelerated the decline trend of the cultivated land, and increased the newly forested land substantially. The area of newly forested land had significantly exceeded that of the natural forest. These changes may reduce soil erosion and water yield, restore the soil structure, and increase the soil organic matter. Most farmers support the SLCP because it can increase farmer’s net income. Nevertheless, the potential negative consequences of SLCP can never be ignored. These findings are not only useful for an integrated understanding over the impacts of SLCP, but also for the planning and decision-making of the eco-restoration projects together with the eco-environmental protection.
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