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作 者 ：吴东辉,尹文英,卜照义

期 刊 ：生态学报 2008年 28卷 1期 页码：1~12

关键词：土壤线虫；中度退化；植被恢复；松嫩草原；

Keywords:soil nematode, gently degraded, vegetation restoration, Songnen grasslands,

摘 要 ：2005年5月~10月对松嫩草原中度退化草地不同植被恢复方式样地进行土壤线虫调查，淘洗-过筛-蔗糖离心法提取土壤线虫，应用类群属数、个体密度、多样性指数和功能类群指数等多个群落参数，研究中度退化草地不同植被恢复方式间土壤线虫群落特征的差异。研究共捕获线虫13 713条，分别隶属于线虫动物门2纲7目24科40属，个体密度平均113条/100g干土。研究结果表明，不同植被恢复方式间土壤线虫群落特征存在一定差异，围栏封育和种植苜蓿均能明显改善中度退化草地土壤线虫群落环境，但围栏封育较种植苜蓿更能显著提高土壤线虫的个体密度和群落多样性。土壤线虫个体密度垂直分布，围栏封育样地线虫表聚性最明显，种植苜蓿样地表聚性次之，过度放牧样地表聚性最差，其夏季和秋季土壤线虫向土壤下层移动明显。此外，研究结果还表明，功能类群指数能够指示中度退化草地植被恢复方式间的差异，其中∑MI指数和PPI指数对于不同植被恢复方式下土壤线虫群落变化反映最敏感，根据功能类群指数统计，与围栏封育相比，种植苜蓿和过度放牧显著改变了土壤线虫群落中r-和 k-选择植物寄生线虫的比例。对于松嫩草原中度退化草地，选择围栏封育方式可能更利于草地土壤线虫群落的恢复与重建。

Abstract:The grassland of Songnen plain has being moderate degraded. Two vegetation restoration practices were applied in the degraded grassland: fencing enclosure, planting alfalfa. The overgrazing was used as a control treatment. Soil samples of three treatments were taken from May to October in 2005. The soil nematodes were collected from soil using sugar flotation and centrifugation method. A total of 13713 soil nematodes were identified to the genus level, which consisted of 2 classes, 7 orders, 24 families, and 40 genera. The ecological index such as Species richness, abundance, diversity index and trophic group index were analyzed. The three dominant groups, Rotylenchus、Aphelenchus and Criconema, accounted for 52.95% of the total individuals. The individual density was 113 inds. per 100 gram dry soil. The considerable difference of the number of groups and individuals varied with soil profile were found among three treatments. In the overgrazed site, the nematodes distributed evenly in the soil in both samples collected in July and October. Because there were intensively grazing activity during summer and autumn, more nematodes appeared in the lower layer of the soil profile. These results illustrated that the types of vegetation restoration significantly affected the species abundance and diversity, and could improve the structure and functioning of soil nematode community. The characteristics of the functional structure of the nematode communities under different types of vegetation restoration were analyzed by using MI (Maturity Index),PPI (Plant Parasite Index),∑MI index and PPI/MI value while Shannon-Wiener index, Pielou index, and Margalef index were also used in analyzing the diversity of the nematode community. The results also showed that ∑MI and PPI were the more sensitive parameters to monitor the changes under differeent vegetation restoration practices. Planting alfalfa and over grazing considerably changed the ratio of r- and k- plant parasite nematodes. In grasslands of Songnen plain，fencing enclosure maybe efficently restores the moderate degraded pasture in comparision with planting alfalfa.

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