长白山苔原带小叶章扩张的生物与非生物机制研究

The tundra of the Changbai Mountains is typical temperate alpine tundra in Asia. Through the field survey and comparison with history data, we found that the herbaceous species, Deyeuxia angustifolia (Kom.) Y. L. Chang, from the mountain birch zone has invaded the alpine tundra zone of the Changbai Mountains. After establishment, D. angustifolia used to form the consociation. The expanding D. angustifolia patches showed great differences with tundra plant communities, which threatened the survival of tundra plants. Take the D. angustifolia expansion as the research object, this research aims to 1) analyze the suitable habitat characteristics of D. angustifolia patches using spatial continuous environment data (topography and soil) acquired from the observation of a 4 ha large plot by geographical information system technology; 2) reveal the spatial association of D. angustifolia and tundra plants using the technology of classification, ordination, and point pattern analysis based on the spatial environment data; 3) illustrate the controlling effects of biotic and abiotic factors on the expanding process of D. angustifolia through multivariate control experiment combined with continuous observation data of large plot; 4) investigate whether environment change, such as climate warming or atmospheric nitrogen deposition, promote the D. angustifolia expansion. Then, the mechanism of D. angustifolia expansion was summarized, which could help to predict the future change of tundra vegetation in Changbai Mountains, provide the scientific basis for indicating the response mechanism of vegetation to environment change, and supply the positive reference for the research of plant upward shift in mountain area at the global scale.

长白山苔原是亚洲最为典型的山地苔原。当前，长白山西坡岳桦林带的禾本科植物小叶章(Deyeuxia angustifolia (Kom.) Y. L. Chang)大量侵入到以低矮灌木为主的苔原带，并形成与基质差异明显的斑块，在不断扩张的过程中威胁典型苔原植物的生存。本研究基于长白山苔原带小叶章上侵现象，通过建立4公顷大样地获取植被分布及环境因子(地形和土壤因子)的空间连续数据，利用GIS技术分析小叶章分布的适宜生境特征；利用植物群落分类排序及点格局分析方法揭示小叶章与苔原植物分布的空间关联性；通过开展多因素控制实验，结合大样地多年连续观测数据，分析生物因素和非生物因素在小叶章扩张过程中的控制作用，并进一步探讨气候变暖、大气氮沉降等环境条件变化对小叶章扩张的影响；最后，归纳总结小叶章扩张机制，为预测长白山苔原带植被未来变化趋势、揭示苔原植被响应环境变化的的机理提供科学依据。

长白山苔原是亚洲最为典型的山地苔原。当前，长白山西坡岳桦林带的禾本科植物小叶章(Deyeuxia angustifolia (Kom.) Y. L. Chang)大量侵入到以低矮灌木为主的苔原带，并形成与基质差异明显的斑块，在不断扩张的过程中威胁典型苔原植物的生存。本研究基于长白山苔原带小叶章上侵现象，通过建立4公顷大样地获取植被分布及环境因子(地形和土壤因子)的空间连续数据，利用GIS技术分析小叶章分布的适宜生境特征；利用植物群落分类排序及点格局分析方法揭示小叶章与苔原植物分布的空间关联性；通过开展多因素控制实验，结合大样地多年连续观测数据，分析生物因素和非生物因素在小叶章扩张过程中的控制作用，并进一步探讨气候变暖、大气氮沉降等环境条件变化对小叶章扩张的影响。.在山地植被变化领域，大量研究以气候变暖为主要切入点，认为温度升高是导致植被变化的主要诱因。本项目通过开展多因子控制实验后，发现小叶章对于温度升高呈现出消极的响应，而对氮添加有着积极的响应。长白山苔原带旅游资源开发，降水增加都为苔原植被带来丰富的氮元素。由此可以看出气候变暖并不一定是山地植被变化决定性的驱动因素。研究结果为预测长白山苔原带植被未来变化趋势、揭示苔原植被响应环境变化的的机理提供科学依据。

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