北方重点生态功能区生态系统服务权衡与协同

北方地区作为我国最重要的生态屏障区，也是我国荒漠化发展最快、生态极为脆弱、受风沙危害最严重的区域。分析了北方地区6个国家重点生态功能区生态系统结构变化和防风固沙、土壤保持、水源涵养、牧草供给等生态系统关键服务多年变化状况，从而客观科学地评价典型生态功能区生态保护效果，总结目前存在的主要生态问题，为重点生态功能区监管和考核提供科学地决策依据。结果表明：1）草地面积除阴山北麓有所增加以外，其他功能区皆减少；荒漠面积在东部三个功能区有所增加，而在西部三个功能区有所减少；草地植被覆盖度皆有所提高，增幅0.4%-7%。2）防风固沙服务除呼伦贝尔有所提升以外，其他功能区皆呈现下降态势；水源涵养在西部塔里木河与阿尔金先上升后下降，中部阴山北麓和科尔沁有所提高，而东部浑善达克与呼伦贝尔呈持续上升态势；各功能区的土壤保持呈现不同程度提升，而牧草供给皆有所下降。3）除呼伦贝尔和浑善达克南端以外，牧草供给与防风固沙服务之间以协同关系为主；除科尔沁西北部和呼伦贝尔东端以外，牧草供给与水源涵养、土壤保持服务之间以协同关系为主。通过生态系统类型变化及供给与调节服务相关关系分析可以看出，生态功能区开垦导致草地减少的现象需要遏制，出现权衡关系的东部区域也是生态保护与生产利用矛盾较大的农牧交错带，需要成为后续保护和修复的重点区域。

Tradeoffs and synergies of ecosystem services in key ecological function zones in northern China

North China is a significant ecological region with the fastest development of desertification and an extremely fragile ecology, and also seriously harmed due to the wind and sand. In this study, we consider six key national ecological function zones that are located in northern China as the study areas. We analyze the changes in the ecosystem structure and key ecosystem services such as sand fixation services, soil conservation, water conservation, and herbage allowance. Sequentially, we evaluate the effects of ecological protection, summarize the primary existing ecological problems, and provide scientific basis for decision-making on the supervision and assessment of key ecological function zones. The results indicated that except in Yinshan, the grassland area in others decreased, and the desert area of three key eastern ecological function zones increased, while that of others in the west decreased. The vegetation coverage of grassland increased from 0.4% to 7.0%. Further, the sand fixation services reduced (except in Hulunbuir); the water conservation services in Tarim river and Aerjin increased at first and then decreased, while it only increased in Yinshan and Horqin. The soil conservation services improved, while the herbage allowance decreased in all the zones. Furthermore, except in Hulunbuir and southern Hunshandak, the relationship between the herbage allowance and sand fixation was mainly synergistic, and except in the northwest of Horqin and eastern Hulunbuir, the relationship between the herbage allowance and water and soil conservation was mainly synergistic. From the changing of ecosystem and correlation analysis between the supply and regulatory services, the phenomenon of reduced grass should be controlled. The transition zone between the cropping area and nomadic area led to a relationship of tradeoff with strong contradiction between ecological protection and production. Hence, these should be key protected zones.