喀斯特生态系统服务功能遥感定量评估与分析

Quantified evaluation and analysis of ecosystem services in Karst areas based on remote sensing

生态系统服务功能评估是人类对自然与生态系统认识成果应用于经济决策的桥梁。西南喀斯特区面临环境恶化和经济社会贫困的双重压力,揭示其生态系统服务功能时空变化特征是实现生态恢复和可持续发展过程中亟待解决的问题。本研究通过多年遥感影像及气象和统计资料等,对喀斯特典型区域桂西北1985～1990～2000～2005年的生态系统服务功能进行了定量评估与分析。其分析结果表明:(1)生态服务功能呈先降后升、总体减少趋势,4个年份分别是1096.52亿元、887.89亿元、1033.84亿元和1062.57亿元。大致呈由西向东、由山区向峰丛洼地减少的空间分布特征。高值区(西部)是减弱区,低值区(东部)是增强区;(2)营养物循环、调节气体和有机质生产等单项生态服务功能较高,总和分别占各自年份72.69%、64.57%、70.18%和72.10%;涵养水源、土壤保持和娱乐文化相对较低,都远低于100亿元。(3)林地和灌木是优势景观类型,也是生态服务功能的主要贡献景观类型,二者总贡献率在各自年份分别为71.22%、70.10%、73.66%、67.03%;居民用地和石漠化地生态服务功能少,总贡献率分别仅为0.90%、0.63%、0.77%、1.14%;(4)各行政区单位面积的生态服务功能变化幅度比较大,分别由23549.70元/hm2、173.5.10元/hm2、22705.1元/hm2、19062.3元/hm2低至9764.71元/hm2、7689.61元/hm2、9537.01元/hm2、7540.79元/hm2。典型喀斯特区单位面积生态服务功能显著增加,非喀斯特区单位面积生态服务功能明显减少。研究表明,喀斯特区域生态环境移民和退耕还林等石漠化控制措施效果显著,有利于生态系统服务的充分发挥。

Study on the service values of ecosystem is the bridge of understanding ecosystem and helping economic decisionmaking. Karst ecosystem faces the problem of eco-comeback and rebuilding in the Southwest of China. Revealing the spatiotemporal variations of its ecosystem service is urgent requirement in the process of ecological restoration and sustainable development. Through the remote images, meteorological and statistic data of many years, the spatial distributions and variations of ecosystem service were evaluated and analyzed for the typical karst area in the Northwest of Guangxi Province in 1985, 1990, 2000 and 2005. The result shows that ： （ 1 ） from 1985 to 2005, total ecosystem services decreased firstly and then increased, but the value in 2005 was less than that in 1985 in general. The estimated values of the ecosystem services in above years are 1096.52 million Yuan, 887.89 million Yuan, 133.84 million Yuan, and 1062. 57 million Yuan, respectively. The trend of spatial distribution is declined from west to east, from mountain to peak-cluster depression areas. The ecosystem services in high-value areas （ the western part of the region） are decreased, while those in low-value areas （ the eastern part of the region） are increased ; （2） The ecosystem services of nutrient cycling, organic production and gas regulation are high, the corresponding total ratios are 72.69%, 64.57%, 70.18% and 72.10%, respectively. While the ecosystem service values of water conservation, soil reservation and recreation and culture are low （below 100 million Yuan each） ; （3） Woodland and shrub are the dominated landscape types, and they are the first two large landscape types contributed to total ecosystem services. The total ratios of them in the four year are 71. 22%, 70. 10%, 73. 66%, 67.03%, respectively. The ecosystem services of residence and rocky land are very low and their total ratios are only 0. 90% , 0.63 %, 0.77%, 1.14% respectively; （4） The change of ecosystem services per unit in every county is distinct, falling from 23549.70, 173.5.10, 22705.10, 19062.30 Yuan/hm^2 to 9764.71, 7689.61, 9537.01, 7540.79 Yuan/ hm^2. The ecosystem service values have been obviously increasing in typical karst areas, but distinctly decreasing in nonkarst areas. Our study indicates that ecosystem conditions are improving because of the application of policies regarding of rocky desertification control, such as ecological migration and returning farmland to forest.