四川岷山火溪河地区人为干扰后的植被组成及分布

Composition and distribution of vegetation after anthropological disturbance in the Huoxi River Region of Min Mountain, Sichuan Province

关键词:  火溪河流域  植被类型  地形  GIS  DEM  森林采伐

Key words:  Huoxihe watershed  vegetation type  topography  GIS  DEM  timbering

摘要:

以平武县地形图、植被图、野外植被调查结果为数据源制作研究区植被图和数字高程模型(Digital Elevation Model,DEM),在Arcview GIS平台下通过植被分类和图层叠加分析法,研究了人为干扰后植被的组成及植被类型在主要地形梯度上的分布特征。结果表明:(1)受人为干扰特别是森林采伐活动影响,研究区针阔混交林消失,针叶林面积缩小,阔叶林和灌丛面积增加。(2)植被类型在海拔梯度上分布规律性明显; 除农田外,其它植被类型在坡度上的面积比例与研究区面积在各坡度段所占比例很相似; 针叶林、阔叶林、农田、灌丛对坡向有明显选择性。(3)人为干扰活动改变了研究区植被类型及其面积比重,并使植被在海拔段上的分布带有明显人类干扰的痕迹。

Abstract:

The data on topography maps, vegetation map of Pingwu County and our vegetation survey were used to make vegetation map and DEM of the studied area. By classifying vegetation and analyzing vegetation map and DEM,the pattern of composition and distribution of vegetation along altitude,slope degree and slope aspect gradients were studied. The results show that:(1)Human disturbance especially timbering has resulted in the disappearing of coniferous and broad-leaved mixed forests in the area. And the area of coniferous forests has shrunk while the area of broad-leaved forests and shrubs has increased;(2)Vegetation distribution shows conspicuous altitudinal gradient. Except for farmlands,the area proportions of other vegetation types are similar with that of the working sites at various position of slope. Distribution of coniferous forests,broad-leaved forests,farmlands and shrubs are influenced by slope aspect;(3)It seems that vegetation types and proportions of their areas in the studied area have been changed by human disturbance,which can be seen along the altitude gradient.