喀斯特地区土地利用变化的生态服务功能价值响应

频繁发生的旱灾已成为限制我国西北半干旱区农业发展和生态环境建设的主要气象因子.以甘肃省榆中县为例,基于农户问卷调查,结合GIS技术,从社会、经济和生态三个角度选择水分敏感因子,构建社会-生态系统,然后根据修正的脆弱度概念性模型计算出干旱环境下农户尺度上社会一生态系统恢复力,并对造成恢复力差异的原因进行了分析.结果表明,榆中县农户社会生态系统对干旱的恢复力依赖于外部胁迫压力(干旱)和内部因素(社会,经济,生态)之间的相互作用.户人口数量、土壤湿度和土壤养分是3个区域农户社会-生态系统共同的水分敏感因子;而其它指标则属于局部区域农户社-生态系统的水分敏感因子.

Economic Response of Ecosystem Service Functions to Landuse Changes in Karst Region

By taking Hechi City of Guangxi Province in karstmountainous region as an example,the economic value of ecosystem service functions was estimated. The economic values of food production per hectare of cropland ecosystem in 1988,1998,and 2003 were used as a base of the study. Then the economic values in the three years were contrasted with the landuse situations in corresponding years so as to find outthe features of economic value changes of ecosystem service functions induced by landuse changes in differentperiods. Results showed thatduring the years from 1988 to 2003,the ecological responses to landuse changes were obvious. Economic values of ecosystem service functions were improved in general. From 1988 to 1998,exceptthe 14. 6 % incrementof economic value for farmland ecosystem,the increments of economic value for other ecosystems were all above 25. 9 %,while from 1998 to 2003,the increments became slow evidently and negative economic value for grassland ecosystem even appeared. Landuse changes were almostaccordantwith the changes in ecosystem economic value. These facts prove thatthe local landuse manner needs to be reformed. Especially,reconstruction of wider unused land and ecological restoration of stony desertification land may bring very significantecological benefits.