南方丘陵山地带土壤保持功能及其经济价值时空变化特征

土壤保持是生态系统提供的重要调节服务之一,在区域侵蚀控制以及生态安全的维持方面具有不可替代的作用。以全国主体生态功能区划中"两屏三带"的南方丘陵山地带为研究对象,在遥感和地理信息系统的支持下,以2000、2005和2010年3期生态系统类型数据为主要数据源,运用通用土壤流失方程(Universal Soil Loss Equation, USLE)分析了南方丘陵山地带生态系统土壤保持功能,并对其经济价值进行动态核算。结果表明:10 a间,南方丘陵山地带土壤保持总量呈上升趋势,土壤保持总量上升了76.79×10⁷ t,森林、灌丛和农田生态系统是研究区土壤保持功能的主要贡献者,总贡献率3个年份分别为82.29%、82.59%和80.58%,不同生态系统土壤保持总量排序为森林> 灌丛> 农田> 草地> 湿地> 人工表面> 稀疏地,土壤保持能力排序为湿地> 草地> 灌丛> 森林> 农田> 人工表面> 稀疏地;10 a间,研究区土壤保持功能总经济价值增加了270.34×10⁸元,总经济价值中以保持土壤肥力价值为主;土壤保持功能经济价值的变化以轻微增加为主,其呈现增加的区域面积和价值增幅大于经济价值减少的区域面积和价值减幅。在对该区域生态系统进行保护的基础上,因地制宜地合理增加植被盖度对防治土壤侵蚀、保持土壤养分可以起到良好效果。

SPATIAL-TEMPORAL VARIATION CHARACTERISTICS OF THE SOIL CONSERVATION FUNCTION AND ITS ECONOMIC VALUE IN THE SOUTHERN HILL AND MOUNTAIN AREA,CHINA

Assessment of ecosystem services is the basis of scientific ecosystem management and sustainable use of natural resources. Today, ecosystem services assessment has become a hot spot in the fields of ecology and ecological economics. Soil conservation service, as one of the most important regulating services provided by ecosystems, guarantees the ecological security and sustainable development of a region. The ecosystem function of the soil conservation was analyzed in the southern hilly and mountainous area in this paper, based on the ecosystem type data of 2000, 2005 and 2010, and the Universal Soil Loss Equation (USLE), with the support of RS and GIS. The results showed that: The total amount of soil conservation presented an upward trend and increased by 76.79×10⁷ t during 2000-2010, and forest, shrub, wetland ecosystem were the main contributors (total ratios were 2.29%, 82.59% and 80.58% in 2000, 2005 and 2010, respectively). Total amount of soil conservation had a significant difference among different ecosystem types with a decreasing order: forestland > shrub > farmland > grassland > wetland > artificial surface > sparsely, While the capacity of soil conservation had a significant difference among different ecosystem types with a decreasing order: wetland > grassland > shrub > forestland > farmland > artificial surface > sparsely; The total economic value of soil conservation function had increased by 270.34×10⁸ Yuan, in which the main type was the economic values of maintaining soil fertility; The main change of economic value of soil conservation function presented a slight increase, and the area where value had increased and its range were more than the decreased and its range. To rationally increase the vegetation coverage through reliable ecosystem management based on local conditions would make good effect in preventing soil erosion and maintaining soil nutrient in the region. However, the soil conservation functions of ecosystems in the region were only one contribution of the overall ecosystem services provided by them. The economic value of other ecosystem services together may be far higher. Therefore we concluded that the total economic value of ecosystem services must be a quite substantial contribution to the human welfare in the local areas analyzed. In addition, it was impossible to replace them by man-made ways. With this work we hoped to contribute to the conservation of soil of the region and the restoration of ecosystem services of soils in the region.