湖南省种子植物物种丰富度与地形的关系

为探讨区域尺度物种丰富度与地形的关系，利用湖南省地方植物志资料和地形图，借助GIS软件等手段，在定量分析湖南省地形的海拔分异特征的基础上，研究了湖南省种子植物的物种丰富度和物种密度沿海拔梯度的变化趋势，以及他们与地形复杂度的关系，得到如下结果：(1) 随着海拔的升高，科、属、种丰富度和物种密度均呈现先增大后减小的趋势，也即物种丰富度和物种密度均在中海拔地区达到最高；(2) 随地形复杂度的增加，物种丰富度和物种密度呈现先增大后减少的趋势，即中等复杂程度的地形，具有较高的丰富度和物种密度。

Richness of Seed Plants in Relation with Topography in Hunan Province

To explore relationship between species richness and topography at a regional scale, topographical features, patterns of taxa (family, genus and species) richness and species density along elevational gradients, and relationships between degree of topographical variation, expressed as coefficient of variation(CV) of elevation, and species richness and species density in Hunan Province were studied by using provincial flora list and DEM (Digital Elevation Model) data. The results indicate that: (1) With an increase of elevation, taxa richness and species density increased first and then decreased, showing a unimodal pattern along an elevational gradient; and (2) with increasing CV of altitude, species richness and species density increased first and then decreased, namely, higher species richness and species density occurred at habitats with a moderate CV value.