基于功能团的高寒草甸退化与恢复的动力学模型研究

高寒草甸是野生动植物资源极丰富的生态系统。近年来，我国高寒草甸发生了严重退化，对人畜生存、生物多样性保护等构成极大威胁。迄今为止，借助于种群动力学还不能完全明确其退化原因，也没有找到长期有效的恢复措施，原因是从种群的角度进行建模，系统维数高，不利于理论分析与数值模拟。为此，本项目引进以相同或相近方式利用共同资源的物种构成的功能团这一重要概念，建立基于功能团为尺度的高寒草甸动力学模型，研究其动态变化规律，分析退化原因，寻找有效恢复措施。首先，针对高寒草甸中全部或部分功能团的动态变化，建立动力学模型，研究其稳定性、周期解、分支等，进而获得高寒草甸演化规律。然后，分析系统对主要参数的敏感依赖性，据此寻找高寒草甸退化原因及有效恢复措施。最后，建立具有恢复措施的动力学模型，分析其动力学性态，研究恢复措施和强度对各功能团动态的影响。项目研究从新视角展开，所得成果将为高寒草甸退化与恢复提供新的理论支撑。

Alpine meadow ecosystem is a crucial ecosystem in our country, which has an abundance of wildlife. However, its recent severe degradation has caused a great threat to the survival of both human and livestock, to the conservation of biodiversity, and to the ecological security. So far, reasons causing degradation have not been fully understood and long-term effective restoration measures have not been found. The objective of this project is to investigate the dynamics of alpine meadow and the reasons causing its degradation, and to seek effective restoration measures by means of dynamics models. Firstly, we build some original models based on functional groups. A functional group is a group of species that exploit the same class of environmental sources in a similar way. We study the evolution of alpine meadows through analyzing the models’ qualitative properties such as stability, periodic solutions, bifurcation, and threshold phenomena. Then we investigate the effect of parameters on key thresholds. This will help us to find the reasons behind degradation and hence to provide possible restoration measures. Finally, we modify the previous models with the incorporation of restoration measures. After obtaining the dynamical behavior and sensitivity of dynamics to the intensity of restoration measures, we will draw the most effective restoration measure. This study will successfully deal with some key issues in the management of degraded alpine meadow, enrich the theory on the degradation and restoration of alpine meadow, and broaden the topics and tools in the study of theoretical ecology.