不同土地利用/覆被情景下生态系统减轻水库泥沙淤积的服务能力与经济价值模拟

以ArcGIS9.2为平台,构建了生态系统减轻水库泥沙淤积服务物质量和价值量评估模型.整合2000年的相关数据将此模型应用于二滩水库,并模拟了10种不同土地利用/覆被情景下集水区生态系统该项服务的能力和在水库使用年限内服务总价值的响应.结果表明:2000年,二滩水库集水区土壤保持量12.1亿t·a-1,高值区分布于雅砻江干流和支流水网附近.泥沙输移比在河道附近和水库周边较高.水库周边是最为主要的保沙区.水库使用年限内,集水区对于减轻二滩水库泥沙淤积服务总价值27.53亿元.集水区内不同结构类型的土地利用/覆被情景对保沙能力所产生的影响各异,模拟保沙量符合林地＞草地＞裸地＞农田规律,农田保沙能力最弱,是二滩水库最为主要的产沙源.

Evaluation on ecosystem service of avoided reservoir sedimentation and its economic value under different land use/cover scenarios

Based on the integrated Geographic Information System (GIS) software package, ArcGIS9.2, a model was established to simulate an ecosystem service of avoided-reservoir-sedimentation and its economic value. Relevant data of the year 2000 were used in Ertan reservoir by this model. The quantity of avoided-reservoir-sedimentation and the economic value of this ecosystem service for the reservoir′s designed operating life(100a) were simulated under ten different land use/cover scenarios as well. The results showed that in 2000, the total quantity of soil retention in the watershed of this reservoir was 12.1×10~8 t · a~(-1). The region with higher soil retention was near the main and branch streams of the Yalong River; The sediment delivery ratio that was near to the stream and the Ertan reservoir was higher. The region with a higher quantity of sediment retention was around the reservoir; For the reservoir′s designed operating life(100a), the total value of the avoided Ertan reservoir sedimentation service in the watershed was 2.75 billion Yuan. The influence that different land use/cover scenarios′ pattern had on the ability of sediment retention was different. The simulated results of sediment retention accorded with the regulation that was: forestland>grassland>wasteland>farmland. The farmland′s ability of sediment retention was the weakest. It was the most important source of sediment yield in the watershed of Ertan reservoir.