三江源生态保护和建设一期工程生态成效评估

Assessment on the effects of the first-stage ecological conservation and restoration project in Sanjiangyuan region

基于生态系统结构—服务动态过程趋势分析,针对生态保护与建设工程预期目标,构建了由生态系统结构、质量、服务及其变化因素构成的生态成效评估指标体系,研究发展野外观测、遥感监测和生态过程定量模拟一体化的监测评估技术体系,评估了三江源生态保护和建设一期工程的生态成效。结果表明：工程实施8年以来,三江源区宏观生态状况趋好但尚未达到1970s比较好的生态状况,草地持续退化趋势得到初步遏制但难以达到预期＂草地植被盖度提高平均20%~40%＂的目标,水体与湿地生态系统整体有所恢复,生态系统水源涵养和流域水供给能力提高,区域水源涵养量达到了增加13.20亿m3目标;重点工程区内生态恢复程度好于非工程区,除了气候影响以外,工程的实施对促进植被恢复具有明显而积极的作用;然而,草地退化局面没有获得根本性扭转,工程实施尚未遏制土壤水蚀增加趋势,一期工程局部性和初步性特点突显出三江源区生态保护任务的长期性和艰巨性。

In this paper, we developed a series of assessment indexes based on the evaluation of ecological effects, which consists of the ecosystem structure, qualities, services, and main impacting factors for these changes. Comprehensive monitoring and assessment methods that focused on the planning objectives of ecological conservation and restoration project were developed based on field observation, remote sensing monitoring and quantitative simulation of ecological processes. Then we assessed the ecological effects of the first- stage of ecological conservation and restoration project in Sanjiangyuan region by adopting the trend analysis of dynamics in ecosystem structure and services. The results showed that since the beginning of the project eight years ago, the macro- situation of ecosystem in this region has been getting better but not reached the best situation in the 1970 s. The continued degradation trends of grassland have been initially contained, but it is difficult to achieve the expected objective of ＂the vegetation coverage of grassland increasing by an average of 20%-40%＂. The wetland and water- body ecosystems have been restored. The water conservation service of ecosystem and water supply capacity of watershed were increased, and the volume of ecosystem water conservation reached the objective of increasing by 1.32 billion m3. The ecological restoration in the project regions tended to be better than that outside the project regions. In addition to climate change, implementation of the ecological conservation and restoration project had obvious and positive effects on vegetation restoration. However, the degradation situations of grassland were not fundamentally reversed, and the implementation of the project has not been curbing the increasing trend of soil erosion. Therefore, the local and preliminary characteristics of the first-stage of the project highlighted the long-term and arduous ecosystem conservation and protection in the Sanjiangyuan region.