大源溪流域马尾松林群落类型划分及物种多样性

Community type classification and species diversity of Pinus massoniana forest of Dayuan Creek

采用可变聚合法、除趋势对应分析(DCA)及典范对应分析(CCA)对楠溪江上游大源溪流域马尾松林群落类型进行划分,并探讨马尾松林群落的物种多样性。结果表明:(1)通过可变聚合法数量分类,将27个含有马尾松的样地划分为8种群落类型,8种群落类型在DCA排序图上具有明确边界,乔木层优势种是理想的森林群落数量分类依据;(2)由于研究区内森林资源受人为经营干扰严重,蒙特卡罗置换检验表明,CCA排序结果无法接受自然环境因子对物种样方的分布解释,不过结合排序轴特征值可以推测土壤有效氮含量与物种分布具有较强的相关性;(3)马尾松重要值与海拔、有效氮及有效磷均呈边缘显著性相关,与乔木层和草本层多样性呈显著负相关;(4)方差分析表明,与针阔混交林和常绿阔叶林相比,马尾松林的乔木层物种多样性明显较低,其灌木层和草本层多样性虽然较低,但与其他群落类型相比均未表现出显著性差异。

The community types of Masson pine forest of Dayuan Creek were classified by using flexible beta clustering,DCA and CCA. Meanwhile,the species diversity in the Masson pine forest was studied. The results showed that：（ 1） 27 sample plots containing Masson pine were classified into 8 community types and the classification showed explicit distribution boundaries in DCA by flexible beta clustering,so the dominant species of tree layer was an ideal basis of the classification to forest community.（ 2） Monte Carlo Permutation Test showed that the result of CCA ordination could not accept that the environmental factors explained the species distribution in plots,because the forest in the research area was seriously disturbed by human activities. However,combined with the eigenvalue of order axes,it was inferred that soil available nitrogen content was strongly correlated with species distribution.（ 3） The importance value of Masson pine had a marginally significant correlation with elevation,soil available nitrogen and available phosphorus contents,while it was negatively related to the diversity of the tree layer and herbaceous layer.（ 4） The analysis of variance showed that,compared with mixed broadleaf-conifer forest and evergreen broadleaf forest,the species diversity of tree layer in Masson pine forest was significantly lower while the differences were not obvious for the shrub and herb layers.