作 者 ：董林水,张旭东,周金星,宋爱云

期 刊 ：生态学报 2007年 27卷 7期 页码：3072~3080

关键词：晋西；黄土丘陵；土石山区；交错地带；灌木种；TWINSPAN分类；DCA排序；

Keywords:Shanxi Province, loess, bedrock area, ecotone, shrub, TWINSPAN, DCA, ordination,

摘 要 ：应用TWINSPAN和DCA多元分析的方法，对晋西中阳县黄土丘陵与土石山区交错地带森林及灌丛群落中灌木种的数量特征进行了统计分析，分别对样方和物种进行了数量分类和排序。调查样方包括了该地区主要的次生森林及灌丛植被类型，共计31个样方。样方TWINSPAN分类结果表明，第一级分类可以将林下灌丛及阴坡灌丛与阳坡（或半阳坡）喜光耐旱灌丛区分开来。进一步的分类，可将各样方划分为8个组。根据各样方中灌木种的二元属性数据分析，TWINSPAN分类可将29个常见灌木种划分为4个组，这种分类可以比较明确的区分物种的空间分布特征，主要分布在土石山区的灌木种和土石山区及黄土丘陵区均有分布的物种被准确的区分开来。DCA排序结果与TWINSPAN分类结果较为一致。样方DCA排序第1轴反映了生境的水分环境条件，第2轴反应了样方海拔梯度的变化，即热量条件的差异。对角线上各样方的排列顺序综合反映了水分、热量、土壤等环境条件的差异。灌木种DCA排序图第1轴反映了各物种分布生境的水分条件，最左边多为分布在林下阴湿环境中的植物种，如美蔷薇(Rosa bella)、红瑞木(Cornus alba)等；而最右边则多为典型的干旱阳坡指示种，如对结木(Sageretia paucicostata)、山桃(Amygdalus davidiana)等。对角线上物种的排序综合反映了各物种的空间分布特征，左上方各物种多数只分布在水分条件相对优越的土石山地区，而右下方各物种不仅在土石山区有分布，而且在干旱的黄土丘陵区也多有分布。

Abstract:The study region was located in Zhongyang County of western Shanxi Provice, China, and the center of this area was at 37°15′N, 111°58′E. Our study area was located across an ecotone between the loess hills and bedrock hills. Quantitative analysis of relationships between vegetation and environment was an effective method in research field of modern vegetation ecology. Quantitative classification (TWINSPAN) and ordination analysis (detrended correspondence analysis, DCA) were used to examine the ecological characteristics of all shrub species and communities in a loess landscape of western Shanxi, China. All 29 shrub species were examined in thirty-one 10×10m2 plots. From TWINSPAN analysis, we classified the plots into 8 types and all tallied species into 9 groups. The DCA analysis provided us with similar results on the shrubs and communities in the landscape. Both classification and ordination analysis of the plots reflected the spatial distribution of shrub communities. The first axis of DCA appeared to be related to moisture; the second axis to the thermal conditions; and the diagonal line in the 2-D ordination diagram to the changes of elevation, temperature and moisture the three important variables determining the distributions of shrub communities in our landscape. The DCA figure of shrub species reflected the spatial distribution of shrub ecotypes and their relationships with the environment. The first axis of DCA appeared to related to drought tolerance of species. Diagonal line of the 2-D ordination diagram of species DCA reflected the spatial distribution of species. The species which lied on the bottom right of DCA figure numerously were distributed in the loess hill area, while the species lied on the top left of the figure mainly were distributed in the bedrock area.