天宝岩国家级自然保护区4种类型泥炭藓沼泽植被组成及其与环境因子的关系

Community composition of four types of Sphagnum wetlands and its relationship with environmental factors in Tianbaoyan National Nature Reserve

基于野外样地调查资料,运用主成分分析(PCA)与冗余分析(RDA)等方法,研究天宝岩国家级自然保护区4种类型泥炭藓沼泽(泥炭藓类型、水竹类型、垂穗石松类型和灯芯草类型)的植被组成、物种多样性特征及其与土壤层和苔藓枯落物层环境因子的相关性.结果表明:研究区内共有植物28科41属44种,4种类型泥炭藓沼泽的物种组成差异性较大,但科属种的分布比较均匀;植物区系分析发现,天宝岩泥炭沼泽植被区系主要由泛热带分布型和北温带分布型2类构成;PCA结果显示,同种类型泥炭藓沼泽各样地的分布较为集中,个别样地分布比较分散,但4种类型泥炭藓沼泽样地之间的差异较大,PCA二维排序图清晰显示了4种类型泥炭藓群落与环境因子之间的相关性;而RDA表明,土壤容重、木本层盖度、土壤自然含水量和苔藓枯落物层最大持水率成为影响其植被组成的主要环境因子,这些因子能够显著解释物种多样性变化的最小组合.本研究结果表明,不同类型泥炭藓沼泽物种组成对环境因子的响应有差异,而环境水分特征是影响其植物组成分异的主要驱动力.

This study aimed to understand the community structure, floristic compositions and species diversity characteristics of 4 different types of Sphagnum wetlands （Sphagnum magellanicum, Pllostachys heteroelada, Palhinhaea cernua, and Juncus effuses） in Tianbaoyan National Nature Reserve and their relationship with environmental factors of soil layer and litter layer, based on information gathered from field survey, with the help of principal component analysis （PCA） and redundancy analysis （RDA）. The investigation showed 44 species, affiliating to 41 genera in 28 families in the wetlands. The species composition was different among the 4 types of Sphagnum wetlands, but their distribution of families, genus and species was quite even. Analysis on the flora area revealed the primary components as Pantropic and North Temperate geographical elements at the generic level. The PCA results showed that the sampling sites in the same type of Sphagnum wetlands clumped with some of them disperse. The relationship between communities and environmental factors in 4 different kinds of Sphagnum wetlands was clearly shown by the PCA ordination diagram. The RDA result suggested that the main factors affecting the community composition in Sphagnum wetlands of Tianbaoyan National Nature Reserve were soil bulk density, woody layer coverage, soil natural water holding capacity and litter layer maximal water holding rate, which can be the minimal combination to explain the species diversity change. It was concluded that the different community composition of four types of Sphagnum wetlands was caused by the environmental factors, which was mainly forced by the water characteristics.