西北干旱区山地-绿洲-荒漠系统生态恢复综合效益评估

西北干旱区目前已实施众多生态恢复举措试图修复和重建受损的生态系统,截至目前恢复效果如何我们不得而知,但生态恢复效益评估却能够检测其结果,并为未来的生态工程提供参考。在前人研究的基础上,以地面观测的气象资料、土壤调查数据、多源遥感数据和陆面模型模拟数据作为输入,对基于像元二分法的植被覆盖度估算方法、修正的风力土壤侵蚀模型、修正的通用土壤流失方程和基于光能利用率的净初级生产力模型中的参数进行本地化,更为准确的估算了西北干旱区生态恢复效益评价体系中的关键指标,并集成生态恢复效益指标,评估了1990—2015年西北干旱区14个山地-绿洲-荒漠子系统的生态恢复效益。研究发现:(1)山地-绿洲-荒漠子系统的生态系统结构、生态系统质量和生态系统功能时空分异明显:全区山地系统的生态系统结构有所改善,北疆和伊犁地区的山地-绿洲-荒漠子系统生态系统质量上升,荒漠生态系统的生态系统功能下降;(2)1990—2015年西北干旱区的荒漠子系统生态恢复效益在下降,而绿洲和山地的生态恢复效益在上升。基于多指标的生态恢复效益定量评估有助于客观认识西北干旱区的生态恢复现状和动态,评估结果可为未来生态工程提供具体的空间位置,也为我国其他生态脆弱区的生态恢复效益评价提供参考。

Effectiveness of ecological restoration in the mountain-oasis-desert system of northwestern arid area of China

A number of ecological restoration measures thus far have been implemented with the attempt to repair and reconstruct the damaged ecosystems in the northwestern arid area of China. However, there is not much available information on the effectiveness of these restoration measures. Assessment for the effectiveness of ecological restoration could serve as a reference for scientists, project designers and managers in related fields. The input grid data for our study were generated from meteorological observations of 86 stations, soil data, multi-source remote sensing images and land surface simulations. We analyzed these data with the universal soil loss equation, revised wind erosion equation, dimidiate pixel model of vegetation coverage fraction, and Carnegie Ames-Stanford Approach to estimate each index. In order to obtain more accurate indices, key land surface parameters were calibrated and localized by the observations from previous studies. Finally, a comprehensive index for the effectiveness of ecological restoration was integrated to assess the effectiveness of ecological restoration in 14 mountain-oasis-desert sub-regions in the period from 1990 to 2015. Our results showed that:(1) the ecosystem structure, quality, and functions of all investigated mountain-oasis-desert sub-systems displayed significant spatio-temporal differences. From 1990 to 2015, the ecosystem structure of the whole study area was improved, and the ecosystem quality of northern Xinjiang and Yili mountain-oasis-desert sub-system areas increased, while the ecosystem functions of the desert declined. (2) During 1990-2015, the effectiveness of the ecological restoration of the desert areas declined, but the effectiveness of ecological restoration of the oasis and mountains increased. Assessment based on the multiple indices for the effectiveness of ecological restoration could be helpful in order to objectively assess and understand the situation and dynamics of ecological restoration in the northwestern arid area of China. The results of this assessment could provide information on specific locations for future ecological restoration projects and they could be a reference for assessing the effectiveness of ecological restoration in other vulnerable regions.