植被生态系统防风固沙功能价值动态变化研究--以榆阳区为例

以榆阳区北部风沙过渡带1988-2003年的土地利用数据为依据,运用按研究区实际情况建立的测算模型,对该区1988-2003年的林草植被的年度防风固沙服务功能价值进行了测算和动态分析.研究表明:(1)1988-2003年,榆阳区北部风沙草滩区林草植被的防风固沙价值在波动中增加,其中1988-1998年和2001-2002年为上升期;1998-2001年和2002-2003年为下降期.(2)榆阳区林草生态系统防风固沙服务功能价值量的变化是国家生态政策、自然因素、经济因素等合力驱动的结果."退耕还林还草"和"营造防护林"等生态措施的实施,对保育风沙区的环境起到了积极作用.(3)人类对生态系统服务功能的干预主要通过改变土地利用方式来实现,土地利用类型的动态变化会产生相应的生态响应.

Study on the Dynamic Change of Value of Vegetation Sand-fixing Effect--A Case Study in the Yuyang Region

At present,most of the researches about the economic value of vegetation sand-fixing effect are static and qualitative,but the studies on the dynamic change and quantitative appraisal are insufficient to guide the formulation of policies and the implementation of measures for conserving and regenerating ecology.In order to solve the problems above,in this paper,a case study on the estimation and dynamic change of the ecological service value of the woodlands and the grasslands in the Yuyang region during the period of 1988-2003,where strong winds sand drift disasters occur frequently,is carried out based on the data of land use in the region,and an estimating model is developed.The results are as follows:(1) The economic value of vegetation sand-fixing effect was increased in a fluctuation way in the Yuyang region during the period of 1988-2003,in which it was increased during the periods of 1988-1998 and 2001-2002 but decreased during the periods of 1998-2001 and 2002-2003;(2) Ecological policies,natural factors and economic factors affected jointly the change of the ecological service value of sand-fixing effect of the woodlands and the grasslands in the Yuyang region during the period of 1988-2003,and the implementation of the policies about building the shelter-forests and returning farmlands to woodlands has improved the ecological environment in the region;(3) The change of the service value of ecosystems are affected by many different kinds of factors,human disturbance to the change of the service value of ecosystems is mainly by changing the land use patterns,and the response of ecological environment to the dynamic change of the land use patterns is sensitive in the Yuyang region.