黄土高原草灌植被生态系统恢复力对气候变化响应的模拟

Grass and shrub are important vegetation types in maintaining stability of ecosystem on the Loess Plateau. They are major vegetation for ecological rehabilitation. How exactly climate change will influence the functioning of these vegetation, or how resistant are these vegetation to climate change before they change their essential structure and function? In this study, we will use a process-based ecosystem model to evaluate impact of climate change (individual and combined changes in precipitation, air temperature and carbon dioxide) on the resilience (quantified by indices such as amplitude, malleability and inertia) of grass and shrub ecosystem on the Loess Plateau. Assess the threshold of projected cliamte change that leads to ecosystem regime shift, and changes in resilience when ecosystem shifts to a new state. The outcome will provide the scientific basis for adapting to climate change, improving ecosystem management and maintaining ecosystem stability in ecological fragile region.

草灌植被在维持黄土高原生态系统稳定性中起重要的作用，是生态建设的主要植被类型。气候变化将在多大程度上影响这些植被正常功能的发挥，或者说这些植被在维持其正常的结构和功能稳定的情况下所能承受气候变化的阈值尚缺乏明确研究结果。本项目以黄土高原草灌植被为研究对象，采用生态系统机理模型，利用幅值（Amplitude）、展性（Malleability）、惯性（Inertia）等指标度量生态系统恢复力，通过定量评估气候因子（降水、气温、二氧化碳）单独的与交互的作用对生态系统恢复力的影响，确定区域生态系统在保持整体结构和功能稳定的情况下所能承受气候变化的阈值，若气候变化超过阈值导致生态系统转换到新的状态，它与原状态相比恢复力增大还是减小，从而为生态脆弱区应对气候变化、促进生态系统管理、维持生态系统稳定提供科学依据。

草灌植被在维持黄土高原生态系统稳定性中起重要的作用，是生态建设的主要植被类型。气候变化将在多大程度上影响这些植被正常功能的发挥尚缺乏明确研究结果。本项目主要研究了黄土高原气温和降水的变化趋势；模拟研究降水和气温单独的与交互的作用对生态系统恢复力的影响。结果表明黄土高原在近50年内气温呈显著升高的趋势；降水量减少且降水变率增加，即呈现出分布更不均匀的趋势。参数化后的生态系统模型具有较好的模拟效果，模拟结果表明半干旱生态系统对降水强度变化比降水频率变化更为敏感；随着降水和/或气温年际变率增大，生态系统净初级生产力年际变率也增大，当降水和/或气温年际变率超过一定阈值后，生态系统将失去恢复力。本项目的研究结果为生态脆弱区应对气候变化、促进生态系统管理、维持生态系统稳定提供科学依据。