松山自然保护区森林群落的数量分类和排序

Numerical classification and ordination of forest communities in the Songshan National Nature Reserve

根据68个森林群落样方数据,采用双向指示种分析(TW INSPAN)方法,对松山自然保护区的森林群落进行分类和采用除趋势对应分析(DCA)、典范对应分析(CCA)方法进行排序。结果表明:(1)TW INSPAN将该区的森林群落分为13类型;(2)样方的DCA排序及样方和优势种的CCA排序较好地揭示了该区森林群落的分布格局与环境梯度的关系;CCA第一轴明显地反映出森林群落的海拔梯度、枯枝落叶层厚度和土壤深度变化,沿CCA第一轴从左到右,海拔逐渐升高,枯枝落叶层越厚和土壤越深;第二轴与海拔高度和坡度成正相关,而与土壤紧实度成负相关。其中海拔梯度是环境因子中对森林群落起决定性作用的因子。(3)与DCA相比,CCA的排序轴更有利于生态意义的解释,后者能同时反映样方间在种类组成上及环境因子组成上的相似性,表现在排序图中样方较集中,群落间的界线变得较模糊,因此如果排序同分类结合使用,DCA的效果要好于CCA。(4)TW INSPAN分类与DCA和CCA排序的结果,同时表明了该地区森林群落的垂直分布格局。

The Songshan National Nature Reserve is located at 115°43＇44″-115°50＇22″（E）,40°29＇9″-40°33＇35″（N）. According to the 68 quadrat data,forest communities in this reserve were investigated by using two-way indicator species analysis （TWINSPAN）,detrended correspondence analysis （DCA）,and canonical correspondence analysis （CCA）. The results showed that the forest communities were classified into 13 types,13 associations,by TWINSPAN. The results of DCA and CCA clearly reflect the relationship between the distribution pattern of forest communities and environmental gradients. The first CCA ordination axis indicates the changes of elevation,litter layer thickness,and soil depth,and along the first CCA ordination axis,the elevation becomes higher,litter layer becomes thicker,and the soil becomes deeper form left to right; The second CCA ordination axis is positively correlated with elevation and slope,and negatively correlated with soil solidity. The elevation is a decisive element to forest community.The ecological meaning of CCA ordination axes is much clearer than that of DCA axes. CCA ordination can simultaneously express similarities of species and environment,and the quadrat location in CCA ordination figure is much closer to each other than that in DCA,and the boundary among forest communities become more ambiguous. Therefore if ordination is combined with classification,the effect of DCA is better than CCA. The results of TWINSPAN,DCA and CCA simultaneously indicates vertical distribution pattern of forest community in this reserve.