长江流域2000—2015年生态系统质量及服务变化特征

分析生态系统质量与服务现状及变化特征，有助于准确了解流域生态系统状况与趋势，为流域生态保护与修复的高效管理提供参考依据.采用相对生物量密度与相对植被覆盖度指数以及生态系统服务（土壤保持、防风固沙、洪水调蓄、粮食生产）评估模型，评估2000—2015年长江流域生态系统质量及服务变化特征.结果表明:①2000—2015年，长江流域森林、灌丛以及草地生态系统质量提升显著，56.56%的森林、45.65%的灌丛以及19.26%的草地生态系统质量得到不同程度的提高.②研究期间，长江流域粮食生产、洪水调蓄、土壤保持、防风固沙均呈显著上升趋势，其中粮食生产能力增加13.7%，洪水调蓄功能提升10.1%，土壤保持服务提高19.5%，防风固沙总量增加30.0%.③长江流域生态系统质量不高，处于低与差质量等级的生态系统面积比例在25%~35%之间；受不同类型的自然和人类活动影响，长江流域生态系统质量与服务均存在局部退化现象.研究显示，在生态质量与服务评估的基础上，分区域、分类型实施不同的生态系统保护与恢复途径，是今后长江流域加强生态系统管理的重要途径. 

Changes of Ecosystem Quality and Services between 2000 and 2015 in Yangtze River Basin

Analysis of ecosystem quality and services and their changes can provide important information on ecosystem management. Using the Relative Biomass Density Index, Relative Vegetation Coverage Index and assessment models of ecosystem service (soil retention, sandstorm prevention, flood regulation and grain yield), the changes of ecosystem quality and services in the Yangtze River Basin from 2000 to 2015 were analyzed. During this period, the ecosystem quality and services increased generally in the Yantze River Basin. The quality improvement areas of forest, shrub and grassland ecosystems accounted for 56.56%, 45.65% and 19.26%, respectively. Correspondingly, grain yield, flood regulation, soil retention and sandstorm prevention increased by 13.7%,10.1%, 19.5% and 30.0%, respectively. However, the overall ecosystem quality in the Yangtze River Basin was relatively low. The area proportion of ecosystems with poor and low quality grades was between 25% and 35%. Because of different nature and human activities impact, ecosystem quality and ecosystem services declined in some regions. Our results highlighted the importance of adopting differentiated ecosystem management approach in different subregions and different types of ecosystem degradation.