Influence of perennial ryegrass on a copper and zinc affected terrestrial nematode community

Effects of copper or zinc (0, 25, 50, 100, 200 and 400 mg kg(-1)) on soil containing an indigenous nematode community were examined in a greenhouse in the presence or absence of ryegrass (Lolium perenne L.). Increasing Cu and Zn additions had negative effects on the total abundance, average number of taxa, proportion of plant feeding nematodes, proportion of omnivorous and carnivorous nematodes, nematode taxa from c-p groups 4 and 5 and the Maturity Index, both in the presence and absence of L. perenne. At intermediate Cu or Zn concentrations of 25-200 mg kg(-1), certain taxa had higher absolute abundances than in the control, which indicated indirect effects. The effects of similar Cu or Zn additions were less extreme in the presence than in the absence of L. perenne. These results imply that the presence of vegetation influences the ecotoxicological effect of pollutants. The risk assessment of pollutants could increase its realism by the inclusion of the response of communities of soil organisms in the presence of plants. (C) 1998 Elsevier Science B.V.