南京北部郊野森林群落物种多样性及其环境解释

【目的】了解南京北部郊野森林植物群落的结构特征、物种多样性及其与生态环境影响因子的关系,为该地区森林植被群落的保护和植物资源的可持续利用提供参考。【方法】采用典型样方法在南京北部(长江以北)的8个自然山体中划定72个面积10 m×10 m的样方,在群落调查的基础上,应用多元回归树(MRT)和典范对应分析(CCA)方法对群落进行分类,分析群落的结构组成、物种多样性以及群落类型与环境因子之间的关系。【结果】①样地中共有维管植物79科203属270种;乔木层以朴树、麻栎的重要值最高,是群落的建群种。②朴树、麻栎等优势物种的数量和分布的均匀性决定了群落的物种多样性,群落表现出物种分布集中、优势明显的特征。③运用MRT分类法将72个样方划分为5个群落:群落Ⅰ主体由栓皮栎(Quercus variabilis)+桑(Morus alba)构成,包含16个样方;群落Ⅱ主体由马尾松(Pinus massoniana)+刺槐(Robinia pseudoacacia)构成,包含15个样方;群落Ⅲ主体由麻栎(Quercus acutissima)+构树(Broussonetia papyrifera)构成,包含13个样方;群落Ⅳ主体黄连木(Pistacia chinensis)+枫香(Liquidambar formosana)构成,包含18个样方;群落Ⅴ主体由朴树(Celtis sinensis)+黄檀(Dalbergia hupeana)构成,包含10个样方。④CCA二维排序将群落分为5组,与MRT分类结果一致,可相互验证。同时,应用CCA排序分析环境因子与群落结构、优势树种的相关性,结果表明海拔、坡度是影响群落物种分布的主要环境因子。【结论】南京北部的郊野森林是维系与提高该区域内植物多样性的重要区域。该区域群落物种多样性丰富,朴树、麻栎等优势树种分布集中、优势明显。除人为干扰外,海拔、坡度、土壤含水率等环境因子对群落结构、植物生长具有明显影响,其中海拔影响最大,土壤含水率、营养元素等对植物的生长也有一定的作用。

Species diversity of communities and environmental interpretation of the suburban forest in Northern Nanjing

【Objective】This study aimed to investigate the structural characteristics, species diversity and the relationship between the plant communities and ecological environment of suburban forest of northern Nanjing, thereby providing basic information for protection of forest vegetation and sustainable utilization of plant resources in the region. 【Method】Based onthe field investigation, information of 72 plots of 10 m×10 m in 8 natural mountains in northern Nangjing (north to the Yangtze River) was collected using a typical sample method. The community composition, species diversity index and relationship between the community types and environmental factors were analyzed; the communities were classified using the multivariate regression tree (MRT) and canonical correspondence analysis (CCA). 【Result】There were 270 species of 203 genera in 79 families collected from the plots. Celtis sinensis and Quercus acutissima were the dominant and constructive species owing to their high important value in the arbor layer. The species diversity of the communities was determined by the number and distribution uniformity of dominant species such as C. sinensis and Q. acutissima, with characteristics of concentrated distribution and obvious domination. Seventy-two plots were divided into five clusters by MRT classification. Association Ⅰ, Ⅱ, Ⅲ, Ⅳ and Ⅴ mainly consisted of Quercus variabilis + Morus alba with 16 plots, Pinus massoniana + Robinia pseudoacacia with 15 plots, Quercus acutissima + Broussonetia papyrifera with 13 plots, Pistacia chinensis + Liquidambar formosana with 18 plots, and Celtis sinensis + Dalbergia hupeana with 10 plots, respectively. The result of CCA two-dimension ordination was basically in accordance with that of MRT classification, dividing the communities into 5 groups. 【Conclusion】Suburban forests in the north of Nanjing are important areas for maintaining and improving the plant diversity of the region, which has high community species diversity, concentrated distribution and obvious domination of dominant species. Environmental factors such as altitude, slope and soil moisture content significantly affected the community structure and plant growth; among them, altitude exhibits the greatest effect, however, soil moisture content and soil nutrients also demonstrate certain effects on the plant growth.