摘要
山地植物物种丰富度海拔分布格局是生物多样性研究的热点之一。以往研究中一般将山体划分为等海拔间距的高度带,以分析物种丰富度的垂直格局,其缺陷在于因各高度带面积不相等而可比性下降。为消除面积不相等的影响,作者利用数字高程数据(DEM,Digital Elevation Model)在地理信息系统(GIS)工具支持下,尝试将贺兰山(海拔范围1,300-3,500m)划分为等面积的数个高度带,从而分析其物种丰富度的海拔格局。结果表明:(1)贺兰山物种丰富度呈现为单峰式海拔格局,峰值出现在海拔2,000m附近。(2)逐步回归分析显示,坡度异质性是解释物种丰富度海拔分布格局的最优因子。高度带的坡度异质性越大,意味着地形的起伏变化越大,反映出生境类型越趋多样化,从而可维持多个物种的共存。(3)贺兰山植物物种丰富度在海拔2,000m附近达到峰值,可能与植被演变历史、气候条件、地形复杂度、生态过渡带和中间膨胀效应的共同影响有关。(4)对山体进行等面积划带,可直接消除面积不相等带来的影响,与等间距划带的方法相比,尤其在物种海拔分布信息准确度较高时更具优势。
Altitudinal pattern of plant species richness along an elevational gradient has often been studied by dividing the mountains into equal-elevation belts. However, comparisons of species richness among different belts with different areas is not appropriate. Based on a Digital Elevation Model （DEM） and Geographic Informational System （GIS）, we divided Mr. Helan （1,300-3,500 m） into several equal-area belts along an altitudinal gradient, and compared the plant species richness among them. The results were as followed： （1） The altitudinal pattern of species richness in Mt. Helan showed a unimodal shape, peaking around 2,000 m altitude. （2） The slope heterogeneity was the primary variable to explain the altitudinal pattern of species richness. High values of slope heterogeneity could reflect the complex topographic features and diversified habitats within a belt, implying a favorable condition for more species to coexist. （3） The unimodal pattern of species richness might result from a combined effect of evolutionary history of vegetation, climates, topographic features, ecotone, and the mid-domain effect. （4） Compared with equal-elevation belts, equal-area belts could directly eliminate the influence of area upon species richness, leading to a more reliable analytic result, especially when the species data were accurate at all altitudinal ranges .
出处
《生物多样性》
CAS
CSCD
北大核心
2007年第4期408-418,共11页
Biodiversity Science
基金
国家自然科学基金(40571001
40671065
40371043)
国家留学基金
关键词
物种丰富度
等面积高度带
海拔梯度
坡度异质性
species richness, equal-area belts, altitudinal ingredient, slope heterogeneity
