DECOMPOSER ANIMAL COMMUNITIES IN FOREST SOIL ALONG HEAVY-METAL POLLUTION GRADIENT

Responses of soil decomposer animals to heavy metal contamination and to concomitant changes in organic matter quality and quantity and in s oil microbial biomasses have been studied along a pollution gradient f rom a Cu-Ni smelter. Samples have been taken separately for nematodes, enchytraeids and microarthropods 0.5, 2 and 8 km from the smelter. Sp ecial attention has been paid to the changes in the collembolan fauna. The sampling sites have been located in homogeneous Scots pine (Pinus sylvestris) forests with podsolic soil profiles. In addition, an expe riment has been carried our. in which intact soil cores have been tran sferred in mesh baskets between the sites 2 and 8 km from the smelter (control samples have been transferred within the sites). Although mos t soil animals seemed to be quite resistant to direct and indirect eff ects of heavy metals, results indicate that certain soil animals like enchytraeids can be useful and easy to monitor when the effects of hea vy metals on soil decomposition systems are assessed.