石羊河流域生态系统服务相互作用的时空变化及驱动机制研究

Spatiotemporal changes and driving mechanism of ecosystem service interactions in the Shiyang River Basin

了解生态系统服务的时空变化及其内部复杂关系对管理生态系统服务是至关重要的。以石羊河流域为研究区,评估流域2010、2015年和2020年6种生态系统服务,分析栅格和乡镇尺度上生态系统服务权衡协同及生态系统服务簇的时空变化,利用增强回归树模型探讨研究区生态系统服务簇的驱动机制。结果表明:(1)各类服务空间分异明显,产水量、碳储量、土壤保持和生境质量呈“西南高-东北低”的空间格局,粮食供应主要集中于流域中部和北部的耕地区,休闲娱乐高值区分布于流域南部及中部和北部人口密集地区;研究期间内各类服务均有不同程度提高,其中土壤保持的增幅最大,碳储量和生境质量增幅较小。(2) 2个尺度上生态系统服务权衡协同作用呈相似性,但权衡协同作用强度不同,总体上表现为12对协同关系,3对权衡关系。(3) 2个尺度上生态系统服务簇的空间格局相似,流域南部分布除粮食供应外其他5种服务为主的服务簇,流域中部和北部民勤绿洲地区分布与粮食供应和休闲娱乐为主的服务簇,其他地区的生态环境相对恶劣,分布其中的服务簇内各项服务供应较低;研究期间内服务簇存在明显的空间和数量转移变化。(4)多种因素在研究区生态系统服务簇的变化中起着重要作用,影响因子在不同年份的影响程度略不相同,其中土地利用类型、归一化植被指数、年降水量和海拔是生态系统服务簇变化的重要驱动因子。

Understanding the spatiotemporal distribution and the internal complex relationships of ecosystem services is essential for their management.With the Shiyang River Basin,Gansu Province,China as the research area,six ecosystem services were evaluated in 2010,2015,and 2020.The trade-off/synergy of ecosystem services and the spatial changes of service bundles on the grid and township scale were analyzed,and a boosted regression tree model was used to analyze the driving mechanism of ecosystem service bundles in the research area.The results showed the following:(1)The spatial differences of various services were obvious.The spatial pattern of water yield,carbon storage,soil conservation,and habitat quality was“southwest high-northeast low”.Food production was mainly distributed in the farming areas in the north-central part of the basin,and the high-value areas of recreational service were distributed in the southern areas and the central parts of the basin and in densely populated areas in the north.During the research period,all kinds of services were improved to varying degrees,with the increase in soil conservation having the largest improvement and the increase in carbon storage and habitat quality having the smallest.(2)The trade-offs and synergies of ecosystem services on two scales showed similarities,but their intensities were different.Overall,there were twelve pairs of synergy and three pairs of trade-off relationships.(3)The spatial patterns of ecosystem service bundles on two scales were similar.In addition to food production,there were five service-related service bundles in the southern part of the river basin.In the central and northern Minqin oasis areas of the basin,there were service bundles related to food production and recreational service.The ecological environment in other areas was relatively harsh.There was no outstanding service supply in the service bundles,but there were obvious changes in the number and space transfer of service bundles during the study period.(4)Many factors played an important role in the changes in ecosystem service bundles in the research area,and the impact factors were slightly different in different years.Among them,land use type,normalized difference vegetation index,annual precipitation,and altitude were the main drivers of the changes in ecosystem service bundles.