中文摘要：

对苏北沿海地区4、9和20年生杨树人工林的土壤动物群落结构进行了调查和分析，结果表明：（1）共捕获土壤动物113994只，隶属3门9纲23目。共有优势类群为甲螨亚目和前气门亚目，共有常见类群为等翅目。（2）各林龄杨树林土壤动物个体密度差异显著（p＜0．05），但土壤动物类群数无显著差异（p＞0．05）；各林龄中土壤动物总密度从大到小依次为：4年生林、9年生林、20年生林，土壤动物的优势类群和常见类群有显著不同。（3）各林龄杨树林土壤层的土壤动物个体密度和类群数显著高于凋落物层的（p＜0．05）。（4）不同林龄林地以及不同季节的土壤动物多样性指数间差异均不显著（p＞0．05）。各林龄杨树林土壤动物群落相似度随季节变化而不同，其中9年生与20年生杨树林的相似度较高。研究表明，不同林龄杨树人工林土壤动物的群落结构特征不同，即不同林龄杨树林改变了土壤动物的多度以及类群结构，但对动物类群数量没有明显影响。

英文摘要：

The author conducted a study on the composition and its dynamics of soil faunas under different age poplar plantations in the coastal area of north Jiangsu. The results showed that：（ 1） There were 113 994 soil faunas in the in-vestigation, which belonged to 3 Phyla, 9 Classes and 23 Orders. The dominanted groups were Oribatida and Prostigma-ta, the common ordinary group was Isoptera. （ 2 ） The taxonomic group number of soil fauna was not significant （ p＆gt;0？05） among different age poplar plantations, while a significant difference of soil fauna individual density （ p＆lt;0？05） was observed in the three sites. The order of soil fauna density was： 4 years old poplar plantation, 9 years old poplar plantation, 20 years old poplar plantation. The dominant groups and ordinary groups of soil fauna community were differnent across the different age poplar plantations. （ 3） The individual density and taxonomic number of soil fauna in 0-20 cm soil layer were significantly higher （ p＆lt;0？05） than in litter of different age poplar plantations. （ 4） The diversi-ty index of soil fauna was not significant （ p＆gt;0.05） among different age poplar plantations and different seasons. Jaccard index of soil fauna communities varied according to the changed seasons among different age poplar plantations, the simi-larity between 9 years old poplar plantation and 20 years old plantation were high. The results indicated that there were different characteristics of soil fauna community in different age poplar plantations, the different age poplar plantations changed the soil fauna abundance and group structure, but has no significant effect on soil fauna group numbers.