增温下高寒草地多项生态系统服务权衡的关键因子及区域模拟

The mechanisms and simulations of tradeoffs of multiple ecosystem services at the regional scale were one of the hottest issues in ecosystem services researches. However, gaps existed in the up-scaling of ecosystem process studies at plot scales to the ecosystem services tradeoffs simulation at landscape scales. This project focuses on the alpine grassland in Bailang village and Lhasa river region, Tibet. The methodology of up-scaling from ecosystem process variation caused by warming, such as variation of species competition and plants carbon-nitrogen-water cycling, to the ecosystem services tradeoffs at landscape scales will be studied. Warming experiments will be set up and plant and soil samples will be taken. The responding of diversity, species composition and plant functional traits and their relationships in natural, fenced and artificial grassland to warming will be studied. Simulating parameters of each regional ecosystem service modeling would be established based on the plot scale ecosystem properties for. Based on the established parameters, ecosystem services models will be coupled to conduct the scenarios analysis of regional ecosystem services tradeoffs caused by warming. This project aimed to explain the impacting mechanism of the varied ecosystem process caused by warming and human intervention on the regional ecosystem services tradeoffs. This project will promote the mechanism studies of regional ecosystem services tradeoffs and provide robust up-scaling method from ecosystem process variation to landscape’s ecosystem services tradeoffs. This project will promote the interdisciplinary researches of ecosystem ecology and landscape ecology.

区域生态系统服务权衡机制与模拟是生态系统服务研究领域重要问题之一，而现有景观尺度生态系统服务权衡模拟通常与样方尺度生态系统过程研究脱节。本项目拟以西藏白朗村及拉萨河流域高寒草地为例，研究增温下样方尺度物种竞争与植物碳氮水耦合等生态过程变化向景观尺度生态系统服务权衡的尺度推绎方法。通过实验样地设置与植被、土壤采样，探索天然、围栏、人工草地物候、多样性、物种结构及植物功能性状的内在联系及对增温的响应规律；构建基于生态因子的区域模拟参数，通过不同模型间通用参数进行模型耦合；并进行增温下区域生态系统服务权衡的情景分析。本项目旨在解释气候变化和人类干扰下生态系统过程改变对区域生态系统服务权衡的影响；能够推动景观尺度生态系统服务权衡机理的探索，提供生态系统过程变化向区域景观生态系统服务权衡尺度推绎的可靠方法，促进生态系统生态学与景观生态学的学科交叉。

针对样方尺度生态过程与区域尺度生态系统服务权衡研究脱节的问题，本项目于西藏藏南河谷区半农半牧村设立不同草地样方，基于多年实测数据，分析了不同草地管理下生态系统服务权衡关系以及关键生态过程因子。利用结构方程模型，辨析了气候、地形、生物多样性和功能性状等因子与生态系统服务权衡的关系及影响路径。结合遥感影像和无人机多光谱影像，探讨了植被影响因子研究在尺度推绎中不确定性的来源。通过引入基于主体模型(Agent based model)及投入产出方法，构建了基于样方尺度生态过程的区域生态系统服务权衡模拟方法，预测了不同生态恢复及补贴政策下村落土地利用的响应及生态系统服务的权衡。提出了基于生态过程的生态系统服务权衡机理：NPP权衡假设；并在该假设的基础上构建了区域生态系统服务权衡定量框架。分别在西藏全区以及半农半牧村落尺度分析了NPP的分配变化；模拟了不同草牧业发展模式下，生态系统供给与调节服务的响应和权衡；实证了在半农半牧村河谷区种植人工牧草，仅需占全村草地7%的面积，便可以做到生产生态功能协同发展，为草牧业发展政策的制定提供了决策支持。.本项目立足生态系统生态学、产业生态学和景观生态学的跨学科分析，通过生态系统服务权衡机理假设的提出以及方法学定量分析框架的构建，实现了样方尺度生态过程研究和区域生态系统服务权衡研究的有机结合，并在此基础上面向生态恢复政策的制定，以定量模拟结果提供决策支持。