泾河流域生态保护政策驱动下的生态系统服务流研究

Understanding ecosystem services how to deliver, deliver to whom, how much benefits are delivered, how the supply-demand pattern through time, is essential to designing and optimizing effective conservation and human development policies. Ecosystem service flow, which has been concerned by researchers recently, is significant in the process of the generation, delivery, transformation and maintenance of ecosystem services, and can be seen as a linkage between the ecosystem services and human wellbeing. In this study, we choses Jinhe watershed as study area, which is the one of most serious soil erosion region, and the one of earliest implementing ecological restoration program region in Loess Plateau. The study focus on quantify and spatially explicit the ecosystem service flow process and its change after ecological protection policies implemented. In the light of the relationship chain of ecosystem services produce – transfer – depletion – consume, using GIS technique and ripe ecosystem model, we try to build an ecosystem service flow assessment model, by distinguish the retention, resistance, consume coefficient of different deliver unit with its heterogeneity characteristics. We application the model to quantify and mapping the deliver path, source – sink pattern, service flow amount and supply – demand pattern of different ecosystem service under ecological protection policies driven. We also try to clarify the spatial relationship between the supply and use of ecosystem services, and to quantify the marginal cost – benefits changes according to the ecosystem services flow changes. We finally integrated all the ecosystem services flow research results, to comprehensively evaluating conservation effectiveness of all the policies implemented in this area, and to reveal the causal linkages and mutual feedback mechanisms between ecological protection policies, regional ecosystem service flows and human well-being. The study would provide theoretical and technical support for the optimal adjustment of regional ecological protection policies, which also would extend and enhance ecosystem services research field and its technique measures.

阐明生态政策实施后生态系统服务供需变化、如何传递、传递给谁、传递量是多少是当前政策评估的难点也是生态系统服务研究的新兴方向。本研究以黄土高原水土流失最严重、实施退耕还林等生态保护政策较早的泾河流域为研究区，以量化生态政策实施后生态系统服务空间流转过程为核心，围绕生态系统服务“形成-传递-耗减-消费”这一主线，通过区别生态系统服务流传递中截留、耗减、消费过程以及载体异质性特征，借助GIS手段，构建生态系统服务空间流转评估模型，评估生态退耕以及封禁保护等政策实施后主要生态系统服务流动路径、源汇格局、空间流量、供需关系，阐明生态系统服务供给与使用的空间关系，量化生态系统服务流变化引起的利益主体福祉边际变化，综合评估生态政策的保护成效，揭示生态保护政策、区域生态系统服务流与人类福祉之间的因果联系和互馈机制，为区域生态保护政策的优化调整提供理论和技术支撑，拓展提升生态系统服务研究的领域和手段。

生态系统服务空间流转研究对生态系统管理有着重要的意义。本研究以泾河流域为例，通过生物物理模型对流域水土生态系统服务时空特征进行评估，识别评估退耕还林还草等生态保护政策的成效，研究构建基于生态系统服务耗减过程、面向对象的生态系统服务流转评估框架模型，对流域水土服务空间流转过程进行量化分析，并分析生态系统服务变化对不同尺度受益者的边际效益及其管理对策。研究结果表明：（1）2000-2015年间，泾河流域生态保护力度不断加大，林、草面积不断增加且主要集中在2010-2015年，除流域下游的礼泉县、泾阳县、杨凌区、渭城区、秦都区和中游的西峰市出现生态系统质量指数下降，流域整体生态系统质量指数呈现增加趋势。（2）退耕还林、退耕还草生态保护成效具有时间和空间差异，流域林地、草地增加区在土壤保持、产水服务变化方面与对照区差异明显，且随着时间增长变化差异减小。（3）流域土壤保持、水源涵养服务呈现相反流动趋势和冷热点格局，土壤保持以中游向上游下游流动为主，水源涵养以上游、下游向中游流动为主，供给区多集中在流域下游中南部，消费区多集中在北部的上游源头区。（4）流域整体生态保护意识和补偿意愿增强，土壤保持、水源涵养服务在县域、子流域、流域尺度在表现出逐步增大的边际效益。研究表明，基于耗减过程和面向对象的生态系统服务流研究能够为生态系统管理提供支撑，未来还应加强基于生态系统服务流的生态补偿及生态产品价值实现等研究。