北方农牧交错带多伦县生态系统服务权衡与协同关系研究

科学理解生态系统服务的权衡/协同关系,对于正确指导生态系统可持续管理实践具有重要意义。以位于北方农牧交错带的多伦县为研究区,基于土地利用/覆被、气象、土壤类型、归一化植被指数(NDVI)以及社会经济统计资料等多种数据,分析了2000年、2015年食物供给、碳固持、土壤保持、防风固沙及产水量5种生态系统服务的时空变化,识别了5种服务的供给热点区,并基于相关分析法从县域、乡镇及不同地类3种尺度上对生态系统服务间的权衡/协同关系进行分析。结果表明:(1)2000—2015年,食物供给与土壤保持量增幅较大,产水量与碳固持的供给量增幅较小,防风固沙量大幅下降,5种服务的空间格局基本保持不变;(2)多伦县1类热点区面积明显增加,3类热点区面积明显减少;面积占比超过50%的草地提供5种服务的能力强于耕地;(3)多伦县生态系统服务的权衡关系主要存在于产水量与土壤保持、产水量与碳固持、产水量与食物供给三对服务中;由于研究区生态系统环境的空间异质性较强,各乡镇和两种地类(草地和耕地)上分别只有4对和3对生态系统服务的权衡/协同关系与县域保持一致;(4)不同土地利用类型、海拔、土壤类型等因素的组合使多伦县乡镇之间及乡镇与县域之间的权衡/协同关系存在明显差异。因此,在生态环境更为复杂的整个北方农牧交错带,更需选取合适的空间尺度进行生态系统服务的权衡/协同关系分析,以指导决策者制定合理的生态系统管理措施。

The trade-off and synergistic relationship among ecosystem services: A case study in Duolun County, the agro-pastoral ecotone of Northern China

Understanding the trade-offs and synergies of ecosystem services (ESs) is of great significance for guiding sustainable management practices within ecosystems. Based on multi-source data on land use and land cover, meteorology, soil types, normalized difference vegetation index (NDVI), and socio-economic statistics, the spatio-temporal variation of five ESs, namely, food supply, carbon sequestration, soil conservation, sand fixation, and water yield, was analyzed in Duolun County, the agro-pastoral ecotone of Northern China. We also identified hot spots for these five ESs'' supplies. In addition, based on the correlation analysis method, the trade-offs and synergies between ESs were analyzed at three scales: county, townships, and different land use types. Results showed that the food supply and soil conservation increased significantly, whereas the water yield and carbon sequestration increased slightly, the sand fixation had an evident decrease, and the spatial pattern of the five ESs basically remained unchanged from 2000 to 2015. The area of the first type hot spot in Duolun county clearly increased, while the area of the third type hot spot decreased. Grasslands with a proportion of more than 50% of the county area could provide these five ESs better than the cultivated land. Trade-off relationships in Duolun County mainly existed among three pairs of ESs: water yield and soil conservation, water yield and carbon sequestration, and water yield and food supply. Due to the spatial and environmental heterogeneity of the study area, there are four pairs of ESs at the township scale were consistent with those at the county scale, and three pairs of ESs at different land use types were consistent with those at the county scale. The combination of different land use types, elevation, soil types, and other factors made the trade-offs/synergies between townships and county in Duolun County obviously different. Therefore, at the agro-pastoral ecotone, where the ecological environment is highly complex, it is more necessary to select the appropriate spatial scale for the trade-offs/synergies relationship analysis and ecosystem management than in other, less complex, ecosystems.