三江源草原生态系统生态服务价值的能值评价

摘要

The Three Rivers Source Region is located in the heart of the Qinghai-Tibetan Plateau and,consid-ering the complexity and sensitivity of the area’s ecological system,it is important to comprehensively evaluate this region’s ecological services in order to be able to maintain and sustainably develop the Plateau environ-ment.Combining sequence classification with emergy analysis,six indexes were selected to measure the 2001-2010 grassland system and to determine the value of ecosystem services in the Three Rivers Source Region.The results show that over the ten-year period the value of ecosystem services varied from 137.5 billion yuan/year to 178 billion yuan/year.From a cut-off point in 2006,the total value of ecological services rose continually. The value of ecological services varies by different grassland types.Rain tundra alpine meadow made up more than 99.5% of ecological value over the ten-year period,a result that reflects the fact that these meadows ac-count for the largest area of all grassland types.The proportional contribution of each grassland type to the o-verall value of ecosystem services does not significantly change on a year-by-year basis.Of the various indica-tors of ecological value,the release of O2 and fixed CO2 hold the largest share,with the two combined account-ing for some 90% of all value.The value of hay provided directly by the grassland ecosystem accounted for a-bout 1% of the total,much lower than the contribution of other ecological services.%三江源地区处于青藏高原腹地，考虑三江源地区草地生态系统的特殊性、复杂性、敏感性，及其所蕴含的巨大的生态服务价值，全面的评价该地区的生态服务价值对于维护该地区生态环境健康和未来该地区经济社会的可持续发展具有重要意义。本研究以草地综合顺序分类法为理论基础，以能值分析法为主要计算方法，选择合适的6项评估指标，对2001－2010年三江源区草原生态系统生态服务价值进行逐项评估。研究结果表明，在过去的10年中，三江源区草原生态系统生态服务价值总量从1375亿元／年上升到1780亿元／年，年际变化较大；从趋势上，以2006年为分界点，2006年后的年份，其生态服务价值总量基本保持上升趋势，且普遍高于2006年前的年份。对不同草原类型进行生态服务价值评价可以看出，多雨冻原高山草甸类生态服务价值占全部草原类型生态服务价值的比例最大，10年中皆超过99．5％，这主要与该草地类型所占的面积比例有关；各类型草地生态服务价值占总价值的比例年际变化不大；在6项指标中，释放 O2与固定 CO2的价值所占总价值比例最大，两者之和约占全部价值量的90％，而直接的草产量价值仅占全部价值量的1％左右，远远低于其他生态服务项目的价值。