小五台亚高山草甸与生境关系分析

RELATIONSHIP BETWEEN HABITATS AND COMMUNITIES OF SUBALPINE MEADOW ON MT. XIAOWUTAI, NORTH CHINA

该文结合野外植被调查,在获取更为详细的景观尺度生境数据基础上,探讨了小五台亚高山草甸植物群落与直接环境因子之间的定量关系。典范对应分析(CCA)的结果表明:1)在小五台的亚高山草甸分布地段,热量、养分和水分条件构成了其生境特征差异的基本格局;2)用效应温度和太阳直接辐射量所表征的热量因子,指示出研究区植物群落最基本的分化,说明热量条件是制约研究区草甸群落分布的最重要的因子;3)养分状况的差异,除了说明生境条件本身的差异外,也在一定程度上指示了放牧干扰对群落分布的影响;4)由地形等因素控制的土壤表层水分状况,则反映了草甸植物群落分布所受到的水分条件影响。

Aims Vegetation-environment relationships are key to understanding and predicting vegetation patterns in mountainous areas. Much research has examined vegetation patterns related to climate and topography; however, most studies have focused on forest and shrubland and habitats or examined relationships of vegetation and environmental factors along elevation gradients. Meadows have rarely been studied. We examined a subalpine meadow on the top of Mt. Xiaowutai （summit 2 882 m）, the highest mountain of Hebei Province, North China, to relate communities to environmental factors. Methods We examined vegetation data in relation to temperature, solar radiation and a soil wetness index simulated by GIS. Two-way indicator species analysis （TWINSPAN） was used to classify herbaceous communities, and the relationship between plant communities and environment was examined using canonical correspondence analysis （CCA）. Important findings The thermal gradient of temperature and direct solar radiation was the key factor correlated with community distribution in the study area, followed by soil nutrients, grazing and soil moisture as refleeted by the soil wetness index, which is controlled by topography. This study indicates that habitat conditions, including temperature, solar radiation, soil wetness and nutrients, are the key factors which determine the distribution pattern of alpine meadow communities.