外来入侵种植物学性状和环境因子间关系的典范对应分析

Canonical correspondence analysis of relationship between botanical characters of exotic weeds and their environmental factors

在浙江金华市郊的不同生境中设立73个样地,通过调查计测样地中外来杂草的生态重要值和34个植物学性状,以及样地中的12个环境因子,分别建立样地-杂草重要值、样地-环境因子和样地-植物学性状3个数据矩阵,应用PC-ORD4.0软件中的典范对应分析模块,探讨杂草分布与环境因子、植物学性状与环境因子间的关系.结果表明:(1)在73个样地中的69个样地被发现有外来杂草分布,共计有32种;(2)典范对应分析表明,土壤水分含量、含沙量、坡度、林冠层郁闭度、土壤翻耕程度、放牧程度、离住宅区距离、建筑程度和交通频度是影响外来杂草分布的主要环境因子;(3)在土壤含水量相对较高的区域,外来杂草多数具有营养繁殖能力、多年生、无地上茎、有根状茎、两侧对称花等植物学性状;(4)在林地中的外来杂草,多数为两年生或具有根状茎、攀缘茎、有棘刺、有毒、叶片较厚等特点;(5)在经常翻耕的土壤中,外来杂草多数为一年生,果实类型多为角果、坚果、胞果等;(6)在住宅周围和交通频繁地段,外来杂草有毒的比例高,种子大、胞果比例较高.

In the suburb of Jinhua City, Zhejiang Province, China, 73 sites were sampled in the different habitats, the ecological importance values of the weeds in these sites were surveyed, and 34 morphological and ecological characters of exotic weeds, 12 environmental factors in these sites were also recorded. The potential relationship between characters of exotic weeds and their environmental factors, and the relationship between the distribution of exotic weeds and the environmental factors were determined by canonical correspondence analysis （CCA） based on the obtained data. The main results are as follows： （1） among the 73 sites, 69 sites were invaded by exotic weeds （totally 32 species） ; the mean number of the exotic weed species per site was 4.68; （2）The CCA ordination showed that soll water content, sandiness quantity, slope, canopy, soil tillage intension, the grazing frequency, the distance from residential area, the interference effect of buildings and the traffic frequency were the main factors influencing the distribution of exotic weeds; （3） the exotic weeds, which are stemless or perennials, or have rhizomes, vegetative reproduction and bilateral symmetry flowers, were often recorded in the soil with higher water content; （4） in woodland, the weeds are often biennials, toxic, or have rhizome, scramble stem, thorn and thick leaves; （5） the weeds in the soil frequently ploughed are often annuals, or have fruits such as pod, nut and utricle; （6） in the residential areas or the environments with heavy traffic, the exotic species are often toxic, or have utricle, larger seeds.