大宁河流域生态系统服务权衡关系梯度效应

深入理解生态系统服务权衡关系是推动生态系统有效管理和实现区域高质量发展的基础。然而，目前涉及生态系统服务权衡关系梯度效应的研究仍相对较少。选取三峡库区大宁河流域为研究区域，对典型平水年份2018年粮食生产、碳固持、土壤保持和产水量4种生态系统服务进行了量化评估和空间制图，探讨了海拔、降雨量、植被覆盖度3种环境因子梯度下生态系统服务的空间分异规律，采用均方根偏差进一步分析了生态系统服务权衡关系梯度效应。研究结果表明：粮食生产在空间上呈现中部、南部高，北部低的趋势，碳固持由西北向东南递减，土壤保持和产水量高值区均分布在西部。海拔、降雨量和植被覆盖度显著影响了生态系统服务，碳固持、土壤保持总体上随着环境梯度的增加而增加，而粮食生产随着3种环境因子梯度的增加呈下降的趋势。从生态系统服务权衡方面来看，碳固持与产水量为弱权衡关系，土壤保持与粮食生产为中度权衡，生态系统服务之间多为强权衡关系。由于多种环境梯度的相互作用，生态系统服务权衡关系随海拔梯度变化无明显规律，植被覆盖度增加显著加强了生态系统服务权衡关系，而降雨量增加显著减弱了生态系统服务权衡关系。因此，今后以流域生态系统服务协调和功能整体提升为目标的生态修复工程中，应更加注重统筹不同环境梯度区域内生态系统服务权衡关系。

Gradient effects of ecosystem service trade-off relationships in the Daning River Basin

A comprehensively understanding of the trade-offs between ecosystem services is a basic requirement for effective ecosystem management and extensively regional development. However, current ecosystem service-related research is less concerned about the gradient effect in ecosystem service trade-off relationships. Taking the Daning River Basin in the Three Gorges Reservoir area as the study area, this study aims to explore the spatial variability characteristics for ecosystem services under three environmental gradients of elevation, precipitation, and vegetation cover fraction, and to analyze the gradient effects of ecosystem services and their trade-offs. Four ecosystem services, including food production, carbon storage, soil retention, and water yield, were assessed and mapped in 2018 by applying the Carnegie Ames Stanford Approach, Revised Universal Soil Loss Equation, and Integrated Valuation of Ecosystem Services and Tradeoffs model. Root mean squared deviation was used to explore the gradient effects of ecosystem service trade-off relationships. The results show that ecosystem services in the Daning River basin were significantly spatial heterogeneity. Specifically, food production was spatially distributed in the southern and central areas and was lower in the northern area, carbon storage decreased from northwest to southeast, high soil retention and water yield were mainly distributed in the west. Elevation, precipitation, and vegetation cover fraction had significantly influenced on ecosystem services. Generally, carbon storage and soil retention were increased with elevation, precipitation, and vegetation cover fraction increase, whereas food production decreased. From the perspective of ecosystem service trade-off relationships, the trade-off relationship between carbon storage and water yield was weak, soil retention and food production showed a moderate trade-off relationship. For most of the ecosystem services, their trade-off relationships were always strong. There was no obvious rule of ecosystem service relationships along the elevation gradient because of interactions among multiple environmental gradients. The increasing elevation only significantly enhanced the trade-off relationships of carbon storage-soil retention, and soil retention-food production, but weakened the relationships between carbon storage and water yield. Moreover, increasing vegetation cover fraction significantly enhanced ecosystem service trade-offs, whereas the increased precipitation had an obvious negative effect. Future ecological restoration projects intended to coordinate relationships among ecosystem services and promote ecological function, should pay more attention to ecosystem service trade-offs in different regions of elevation, precipitation, and vegetation cover fraction gradients. Overall, this study provides a special study perspective of ecosystem service and trade-offs, and the results obtained in this study could also be used to guideline the planning strategy of ecological restoration.