上海地区早春非耕地杂草分布与环境因子关系的统计生态学研究

野外调查发现上海地区早春非耕地杂草共106种，隶属于29科88属．计测了261个样地1305个样方中杂草的生态重要值和6种主要环境因子，应用典范对应分析作出了反映106种杂草与6种环境因子关系的二维排序图，应用双向指示种分析对106种杂草进行了有生态学意义的定量分类．根据6种环境因子与前两个排序轴相关系数的大小，发现土壤水分、土壤翻耕程度、人迹出没程度、交通影响程度是影响上海地区早春非耕地杂草分布的主要环境因素；根据双向指示种分析，结合典范对应分析的结果，可以从106种早春中分出五个生态类群，即类群Ⅰ：湿生淤泥海边滩涂杂草类群，类群Ⅱ：相对干燥海边滩涂杂草类群，类群Ⅲ：干扰相对较小的人工林地杂草类群；类群Ⅳ：干旱、开阔、干扰较重环境中的杂草类群；类群Ⅴ：湿润、开阔、干扰较重的弃耕农田环境中的杂草类群．

Statistical Ecological Research on Relationship of Early Spring Weeds in Non-Fields With Environmental Factors in Shanghai Suburb

106 early spring weeds, which belong to 29 families, 88 genera,were recorded from 261 sites, 1305 samples in non-fields in Shanghai suburb, and their importance values and six environmental factors were also surveyed. Based on these datas, three two-dimensional ordination plots of 106 early spring weeds with six environmental factors using canonical correspondence analysis （CCA） and a dendrogram using two-way indicator species analysis （TWINSPAN） were drawn in this paper. The relationship of weed ecological distribution with six environmental variables was discussed. According to the correlation coefficients of six enviromnental variables with the first two axises, the main environmental variables influencing the distribution of 106 early weeds in non-field habitats in Shanghai suburb were soil water content, disturbed intensity by plough, disturbed intensity by people travel, disturbed intensity by conveyance. Based on the two-dimensional ordination plots and the dendrogram , five ecological groups could be identified from 106 weeds： Group Ⅰ （species mainly in sea wet-land）, GroupⅡ （species mainly in sea dry beach）, Group Ⅲ （species mainly growing under artificial woods with thin disturbance）, Group Ⅳ （species from dry, open abandoned fields disturbed heavily）, and Group Ⅴ （species mainly from drier, open habitat.s with intense disturbance）.