Soil biota and upper soil layer development in two contrasting post-miningchronosequences

Density and community composition of a wide spectrum of soil organisms (fun gi, algae, testate amoebae, nematodes, enchytraeids, lumbricids, oribatid m ites, diplopods, terrestrial isopods, collembolans and dipteran larvae), di rect counts of bacteria, rate of cellulose decomposition and microstructure of upper soil layers were studied in two chronosequences of plots reclaime d from open-cast coal milling near Cottbus (Germany) and near Sokolov (Czec h Republic). German plots were characterized by acidic sandy soils and affo rested with pine, while the Czech plots possessed alkaline clay soils and w ere afforested with alder. in both chronosequences, density and species ric hness in most of investigated groups of soil biota gradually increased with increasing succession age. Typical pioneer species were found in initial s tands of both chronosequences. Nevertheless, the initial stands supported p oorer assemblages of soil biota in the Cottbus area than did those in the S okolov area. The Cottbus area was characterized by a moor type of humus and by gradual uniform increase of abundances and species numbers of most stud ied groups of soil biota. On the contrary, moder type of humus and a more v ariable pattern of soil biota development during the course of succession w ere found in the Sokolov area. Slower development of soil biota in initial stages of succession in Cottbus is caused by unfavourable physical and chem ical conditions of heap substrates, and by lower input and poor quality of litter in pine plantations. (C) 2001 Elsevier Science B.V. All rights reser ved.