土地利用变化对生态服务价值的影响——以广西隆林县和西林县为例

Effects of land use change on ecological service values:A case study in Longlin County and Xilin County,Guangxi

为明确石漠化地区土地利用变化对生态服务价值(ESV)的影响。以广西典型石漠化区——隆林县和西林县为研究区,结合遥感解译与实地调查,分析2004—2010年土地利用变化特征;采用Costanza估算生态服务价值方法,基于谢高地的生态服务价值当量因子表,定量评价该区土地利用变化对9项生态服务价值(气体调节、气候调节、水源涵养、土壤形成与保护、废物处理、生物多样性保护、食物生产、原材料、美学景观)的影响。结果表明:研究期间,隆林县和西林县的林地、草地、建设用地面积均呈增加趋势,耕地、水域和未利用地面积则减少。两县总生态服务价值分别增加6.14亿和3.27亿元;除废物处理和食物生产价值减少外,其余7项价值均增加;林地生态价值构成ESV的主体。敏感性分析表明,研究区的ESV估算值相对稳定;生态经济协调度分析表明,两县的生态经济系统分别处于中度协调和潜在危机水平,说明隆林县生态环境有所改善,西林县需要加强生态建设。ESV可作为衡量石漠化地区生态环境的1个综合性指标,为当地制定生态环境保护政策提供参考依据。

[Background]Evaluation of Ecological Services Value（ ESV） is fundamentally important for measuring the sustainable level of social and economic development. Land use change affects ecosystem service value,through the interaction between ecological processes and services. In order to quantify the effects of land use change on the ESV in rocky desertification region,two counties（ Longlin and Xilin）with rocky desertification in Guangxi were taken as research area. [Methods] Land use change of the research area during 2004-2010 was analyzed, based on remote sensing data validated with field investigation. The Costanza ＇s calculation method was employed to quantitatively evaluate 9 types of ecological service values（ i. e.,gas regulation,climate regulation,water conservation,soil formation and protection,waste treatment,biodiversity conservation,food production,raw materials,and aesthetic landscape）. On the basis of the Xie Gaodi＇s equivalent weight factor of ESV,as well as combining with the local economic value of grain yield and costs of farmland,the coefficients of ESV of different land use type（ per unit area） in the research area were estimated. [Results] Results showed that the areas offorest land,grassland,and construction land increased in both Longlin and Xilin,while arable land,water area,and unused land declined during 2004-2010. The coefficients of ESV in Xilin were higher than those of Longlin. The total ESV of Longlin and Xilin increased by 6. 14 × 108 and 3. 27 × 108 Yuan,respectively. The ESV of waste treatment and food production reduced, while the other 7 ESVs increased. The ESV of forest land was the dominant component. In order to verify the reliability of coefficients of ESV,the coefficients of ESV adjusted up or down 50%,respectively,the sensitivity coefficients of each land use type was less than 1. Sensitivity analyses indicated that ESVs were relatively stable in the research area and the results were credible. Analyses of eco-economic harmony degree indicated that eco-economic system was moderate in Longlin,and in the potential crisis in Xilin,respectively. [Conclusions] This study revealed that the total ESV increased was mainly due to the improvement of forest cover. The ESV of forest land was the major ecosystem service value. Ecological value is much greater than productive value of the ecosystem. The ecological environment has been improved in Longlin, but the ecological and economic development was in a low level in Xilin.Therefore,the ecological environment should be maintained in Longlin,and strengthened in Xilin. The ESV can be used as a comprehensive indicator to weigh the sustainable development of ecological environment in the rocky desertification region,which may provide reference for formulating the policies on ecological environment.