北川震后植被恢复工程植物群落物种多样性及优势种生态位

Species diversity of plant community and the niche of dominant species in Beichuan after earthquake engineering

为探究工程治理后植物群落的恢复效果,本文运用数量生态学方法对北川震后工程治理植被的物种组成和多样性指数及其与环境因子间的关系、优势种生态位特征进行了研究。结果表明:(1)研究区有植物74种,隶属于37科72属,工程区木本层和草本层优势物种分别为李子(Prunus salicina)和鬼针草(Bidens pilosa),自然区木本层和草本层优势种分别为柏树(Platycladus orientalis)和扁竹根(Iris confusa)。(2) CCA排序结果显示,工程区物种可分为5个类群,自然区分为3个类群。影响工程区物种分布的环境因子(包括工法)顺序为:海拔>坡度>坡向>pH>工法>土壤含水量>坡位,海拔、坡度和坡向是影响工程区物种分布的主要因素,自然区物种分布受各因子影响均较大。(3)自然区木本植物丰富度和多样性明显高于工程区,工程区草本植物丰富度和多样性高于自然区。RDA排序结果显示,海拔是影响工程区草本层丰富度和多样性的最主要因子,坡位和工法是影响工程区木本层丰富度和多样性的主要因子。(4)与自然区相比,工程区生态位相似性(0.0～0.4)和生态位重叠值(0.0～0.5)大部分处于低值区,种间竞争较弱。综合以上结果,我们认为工程植被有一定的恢复,但不够理想;建议工程区增植自然区的木本优势植物。

To explore the effects of vegetation restoration after engineering application,we examined species composition,diversity,their relationships with environmental factors,and the niche of dominant species of restored vegetation after the Beichuan earthquake in Sichuan Province. The results showed that:( 1) There were 74 plant species in the study area,belonging to 37 families and 72 genera. The dominant species in the woody layer and herb layer of the engineering area were Prunus salicina and Bidens pilosa,respectively,while the dominant species in the respective layers of the natural area were Platycladus orientalis and Iris confusa,respectively.( 2)Results of CCA ordination showed that species could be divided into five groups in the engineering area and into three groups in the natural area. The importance of environmental factors( including engineering methods) affecting the species distribution in the engineering area was in order of: elevation > slope > aspect > p H > engineering method > soil moisture > slope position.Elevation,slope,and aspect were the main factors affecting species distribution in the engineering area. Species distribution in the natural area was affected by various factors.( 3) Species richness and diversity of woody plants in the natural area were significantly higher than that in the engineering area,while the species richness and diversity of herbaceous plants in the engineering area were higher than that in the natural area. Altitude was the most important environmental factor affecting species richness and diversity of herbaceous layers in the engineering area,while slope position and engineering method were the main factors as for the woody layer in the engineering area.( 4) Compared with the natural area,lower niche similarity ratio( 0.0-0.4) and niche overlap value( 0.0-0.5) of most species suggested weaker interspecific competition in the engineering area. Therefore,we proposed to plant more native dominant woody species in the engineering area.