The impact of a copper gradient on a microarthropod field community

In order to evaluate the power of laboratory toxicity tests to predict the situation in the field, soil microarthropods were studied at the population and community levels in a copper contaminated field, and data were compare d to the outcome of single species laboratory tests in the same soil type f rom a companion study. In addition to copper, the influence of several soil characteristics and plant cover data on soil microarthropod abundance and distribution was tested. Total microarthropod abundance was highest at inte rmediate copper concentrations, and linearly related to grass biomass. For single species populations no clear picture of abundance in relation to soi l copper was seen. Two collembolan species, Folsomia quadrioculata and Fols omia fimetaria, were among the most sensitive. The Shannon-Wiener index of biodiversity decreased linearly with increasing soil copper concentrations. The application of multivariate statistics showed copper to be the paramet er best fitting the distribution of microarthropod species in the field. A distinction could be made between sampling points with 50-199 mg Cu/kg soil and those with higher copper concentrations. The species composition of th e microarthropod community was not correlated with plant species diversity or total grass biomass, but was affected by a nearby row of tall trees. Com munity analysis of field data proved as sensitive as laboratory testing, an d seemed superior to single species field population data concerning detect ion of copper effects on soil microarthropods.