Soil invertebrates in semi-coke heaps of Estonian oil shale industry

Abstract

Semi-coke is classified as an environmentally harmful residue of oil shale industry due to its toxic components: several organic and inorganic compounds - oil products, asphaltenes, phenols, PAHs, sulphuric compounds. The aim of the present work was to compare the abundances and species compositions of soil invertebrate assemblages (Collembola, Lumbricidae, Araneae, Myriapoda, Coleoptera) in the artificial substrate from vegetated and bare residue sites of semi-coke heaps of Estonian oil shale industry. Invertebrate communities in semi-coke heaps were studied at three heights of each heap slope; all sampling points in the heaps were divided into four groups based on plant cover. The authors concluded that the communities of micro- and macroarthropods and earthworms in oil-shale processing waste heaps were formed under certain conditions - a high pH and extremely low moisture. The presence of several invertebrate groups (springtails, earthworms, epigeic predators, etc.) and soil communities can be used for monitoring the success in restoration.