Soil nematode responses to heavy metal stress

The effect of Cu and Zn on soil nematode communities at the depth of 0–20 cm was investigated along a pollution gradient with increasing distance from a copper smelter in Northeast China. The results showed that the abundance of total nematodes significantly increased with increasing distance from the smelter, and nematode taxon richness also exhibited an increasing trend. Twenty genera were observed in our study, and Paratylenchus was the dominant genus at all the sampling sites. The numbers of total nematodes, bacterivores, plant parasites, omnivores-predators and the values of NCR (Nematode Channel Ratio) negatively correlated with total Cu (P < 0.01), total and available Zn (P < 0.01). The values of SI (Structure Index) negatively correlated with total Cu (P < 0.05). Among the nematode ecological indices examined, NCR and SI were found to be sensitive indicators for assessing the effect of heavy metals on soil nematode communities in this study.