豚草入侵对中小型土壤动物群落结构特征的影响

豚草(Ambrosia artemisiifolia)是菊科豚草属的恶性杂草,在我国华南地区已成功入侵并造成严重危害。为了解豚草入侵对中小型土壤动物群落的影响效应,采用野外样地试验法研究了豚草入侵地中小型土壤动物的群落特征。全年4次采样共获得中小型土壤动物4174头,隶属于4门11纲26类,其中线虫类为优势类群,蜱螨目和弹尾目是常见类群。结果显示,豚草入侵改变了中小型土壤动物群落的结构特征,入侵地中小型土壤动物的总个体数以及线虫类、弹尾目动物的个体数显著增加,但中小型土壤动物类群数的变化不明显;在群落的物种多样性方面,豚草入侵显著提高了群落的密度-类群指数,物种丰富度、优势度指数亦有所上升,但差异不明显,而均匀度、Shannon-Wiener指数则趋于下降;在群落相似性方面,入侵区与其它处理区的差异较小。豚草入侵所引起的局部气候环境、凋落物、根系分泌物与土壤理化性质的变化可能是造成中小型土壤动物群落结构特征改变的主要原因。

Impacts of Ambrosia artemisiifolia invasion on community structure of soil meso- and micro- fauna

Ambrosia artemisiifolia, a notorious exotic weed of Asteraceae family, has invaded successfully in southern China and caused lots of serious damages to native ecosystem. In order to understand the influences of A. artemisiifolia invasion on soil fauna, we surveyed the properties of soil fauna community through sampling in four kinds of field plots (including heavily-invaded plots, newly-invaded plots, grassland plots and native vegetation plots), where A. artemisiifolia was invading a native abandoned-land at the outskirts of Shaoguan city, Guangdong, China. 4174 individuals of soil meso- and micro- fauna were obtained through 4 samplings in 2009-2010, which belonged to 4 phyla, 11 classes and 26 orders, and Nematoda was dominant group, while Acarina and Collembolan were common groups. The results showed that A. artemisiifolia invasion altered the structure characters of soil meso- and micro- fauna community. The numbers of total individuals, Nematoda and Collembolan were increased significantly and the groups were maintained relative stability in A. artemisiifolia invasion plot. Compared with the other three treatments, Density-Group index(DG) was significantly increased in the heavily-invaded plot, and Margalef richness index(D) and Simpson dominance index(C) were tended to ascend but Pielou evenness index(E) and Shannon-Wiener index(H') were inversed. Similarity coefficient was not significant between A. artemisiifolia invasion plot and the other two plots. The changes of local climate conditions, plant litters, root secretions and soil phycial-chemical properties associated with A. artemisiifolia invasion might be the major factors influencing the community structure of soil meso- and micro- fauna.