人为干扰下雅安市雨城区青衣江河岸带草本植物群落物种多样性及生态位的研究

以雅安市雨城区段青衣江河岸带的草本植被为研究对象,采用典型样地法选取沿岸受3种不同强度人为干扰的样地(轻度干扰的河滩地、中度干扰的割草地和重度干扰的弃耕地),探究不同人为干扰强度对青衣江沿岸的草本植物群落物种多样性和生态位的影响。结果表明:在3种类型的样地中共观测到64个物种,隶属于26科53属,物种数随着干扰强度的增加而降低;分析重要值发现,不同干扰强度下群落的主体均为菊科(Compositae)、禾本科(Gramineae)、蓼科(Polygonaceae)和豆科(Leguminosae)的种类,各物种重要值的差异不大,优势种不明显,种间竞争激烈;受不同干扰强度群落的生境存在差异,轻度干扰、中度干扰和重度干扰群落的生态位重叠值在0.5以上的物种数比率分别为95.0%、85.4%、74.2%,受不同强度干扰群落之间的物种相似程度不同,轻度干扰与中度干扰、中度干扰与重度干扰、轻度干扰与重度干扰的群落相似性系数分别为0.733、0.719、0.625;受不同强度人为干扰的群落中物种丰富度指数D值和Shannon-Wiener多样性指数H值的大小排序为轻度干扰中度干扰重度干扰,但Simpson指数H'值和Pielou均匀度指数Jsw值在样地之间的差异不显著。

Effects of human disturbance on species diversity and niche of herbaceous plants along Qiyijiang riparian zone in Ya'an City, Sichuan Province

In order to make a thorough inquiry in effects of human disturbance on herbaceous plant community,an investigation has been conducted along Qingyijiang River riparian zone,Ya''an City,Sichuan Province by using the typical sampling method. The species Richness index D,Shannon-Wienner index H,Simpson index H'' and Pielou index J_sw were adopted to make evaluations on the level of species diversity on herbaceous plant community. There are three kinds of sample areas under human disturbances of three different intensities in the investigated zone: flood lands under slight disturbance,mow grasslands under medium disturbance,and abandoned farmlands under severe disturbance. The results showed that sixty-four plant species that belong to 26 families and 53 genera were found in the three kinds of studied areas. Species richness significantly decreased with the increment of disturbance intensity. By analyzing the important values,it was discovered that under disturbances of all levels of intensities,the main bodies of the communities are composed of the species which belong to Compositae,Gramineae,Leguminosae,Polygonaceae and Umbelliferae. However,there was no obvious main edificatory in the communities under disturbances of different levels of intensities,since the important values of each species has no significant difference,indicating the intenses of interspecific competitions. The results indicated that the numbers of the species with niche overlap values above 0.5 in communities under light disturbances,medium disturbances and severe disturbances respectively accounted for 95.0%,85.4% and 74.2% of the total species numbers. Sørensen''s similarity coefficient(S_S)between communities under disturbances of different levels of intensities were different. Sørensen''s similarity coefficient(S_S)between communities under slight and medium disturbances,medium and severe disturbances,and slight and severe disturbances were 0.733,0.719 and 0.625,respectively. Species richness index D and Shannon-Wiener index H decreased with the increment of the human disturbance intensity,the sequences of them were slight disturbance>medium disturbance>severe disturbance,and the difference among disturbance intensities were significant. However,there was no significant differences of Simpson index H'' and Pielou index J_sw among sample areas.