小五台山亚高山景观尺度水热条件与植被关系

以河北省小五台山为研究区,通过转化糖方法获取亚高山不同景观部位效应温度,结合DEM模型模拟研究区内太阳直接辐射以及土壤湿润度系数,进而构建生境干燥度指数。以此为基础,在景观尺度上定量分析研究区内亚高山带水热条件与森林和亚高山草甸植被分布格局的关系。结果表明,① 研究区域中森林分布地段生境的太阳直接辐射,效应温度和干燥度指数都显著低于草甸分布地段,土壤水分系数则恰恰相反;② 综合太阳直接辐射或效应温度与土壤湿润度系数的干燥度指数统计分析结果,优于分别以各个因子单独进行分析的结果;③ 在植被格局的形成中,干燥度起着至关重要的作用,这与在水平地带中,森林与草原植被的分布格局受干燥度控制的规律相一致。

Relationship between Light, Temperature, Soil Wetness and Vegetation at Landscape Scale in a Subalpine Belt of Mt. Xiaowutai

In this paper, the aridity indexes of different habitats in Mt. Xiaowutai were calculated through measuring the effective temperature by means of sugar inversion method, and simulating direct solar radiation and soil wetness index supported by DEM and GIS tools. Furthermore, the relationship between vegetation distribution pattern and the above factors in the study area was analyzed by ANOVA at the landscape scale. The results showed: 1) the values of direct solar radiation, effective temperature and aridity indexes at the forest habitats were significantly lower than those at the subalpine meadow habitats, while the value of soil wetness index appeared an inverse tendency; 2) the aridity indexes, defined as the ratio of either effective temperature or solar radiation to soil wetness index, could interpret the distribution pattern of forest and meadow vegetation better than the effective temperature or soil wetness itself only; and 3) the aridity indexes played a leading role in the distribution patterns of forest and subalpine meadow in the study area, which was consistent with the principle followed by the horizontal distribution pattern of forest and steppe vegetation in a regional scale.