南四湖流域关键生态系统服务的时空权衡关系

从多尺度科学地研究流域各生态系统服务间的权衡与协同关系，对流域实现经济发展与生态保护双重目标具有重要研究意义。运用InVEST模型模拟评估产水量、水质净化、土壤保持、碳存储、生物多样性维持和授粉等6类区域关键生态系统服务，并通过热点分析、相关分析和主成分分析，定量分析自改革开放以来（1980-2018年）这些生态系统服务的时空变化及其在不同尺度上的权衡关系。结果表明：（1）南四湖流域产水服务呈上升趋势，而水质净化、土壤保持、碳储存、生境质量、授粉等服务则总体呈下降趋势。（2）研究区东部林地和草地广布，是碳存储、生境质量和授粉服务的高值区，而建设用地分布的地区是产水量和土壤保持服务的高值区。（3）产水量与水质净化服务之间呈权衡关系，水质净化与生境质量、碳存储与授粉之间则存在较强的协同关系。（4）在子流域尺度上主要是存在着供给服务（产水量）与调节服务（水质净化和土壤保持）、供给服务（产水量）与支持服务（生境质量）之间的空间权衡关系；在县域尺度上，供给服务、调节服务与支持服务（产水量、水质净化、碳存储、生境质量和授粉）之间主要是空间协同关系，两个尺度之间具有较大差异。研究结果可为管理者在合适的空间尺度上制定相应的政策提供科学支撑，促进南四湖流域生态环境和社会经济协同发展。

Spatio-temporal dynamics of tradeoffs between crucial ecosystem services in Nansihu Lake Basin

It is important to create a win-win situation on both economic development and ecological protection. For better ecological management and protection in the future, it is essential to identify the trade-offs and synergies of multiple ecosystem services (ESs) at differently spatial scales. The relationships of ESs varied over time and spatial scales, it is important to study the spatio-temporal dynamics of relationships to realize the trends of ESs change and determine appropriate scale to manage. However, the spatio-temporal dynamics of ESs relationships in the Chinese large basin remain a challenge, as information on adaptable unit to ESs management is often insufficient. Therefore, the purpose of this research is to identify relationships of ESs on sub-watershed and county scales. Six key ESs in Nansihu Basin were selected to simulate and evaluate by InVEST (Integrated Valuation of Ecosystem Services and Tradeoffs) model since the reform and opening-up (1980-2018), which included water yield (WY), water purification (WP), sediment delivery ratio (SDR), carbon storage (CS), habitat quality (HQ), and crop pollination (CP). In this paper, the spatial distributions of six ESs were analyzed and the hotspots of each ES were identified by hot spot analysis in ArcGIS 10.2. Moreover, the spatial and temporal dynamics of relationships among six ESs were analyzed through correlation and principal component analyses via the correlation and principal component analyses. And further analyses were performed on different scales to the relations. The results displayed as follow:(1) in the Nansi Lake Basin, the WY was increasing from 1980 to 2018, while WP, SDR, CS, HQ and CP were decreasing during this periods. (2) The land use types in eastern basin were mainly forest and grassland, which possessed high levels of CS, HQ and CP. The areas with construction land suggested high levels of WY and SDR. (3) There was a significant trade-off relationship between WY and WP, as well as strongly synergetic relationships between WP and HQ, CS, CP occurred in the basin. (4) There was a great difference in relationships between sub-watershed and county scale. Trade-offs mainly occurred between the provisioning service (such as WY) vs the regulating services (such as WP and SDR) and provisioning service (such as WY) vs the supporting service (such as HQ) on sub-watershed scale. While on the county scale, there was a synergetic relationship between the provisioning service and regulating services vs supporting services (such as WY, WP, CS, HQ, CP). Our research provided an assessment framework to spatio-temporal dynamics of ESs relationships, which suggested that sub-watershed unit was suitable for ecological management. Based on the results of different spatial scales, this research provided scientific support for managers to formulate corresponding strategies at appropriate spatial scale and promote eco-economic coordinated development in the Nansihu Lake Basin.