Effects of long-term, geogenic heavy metal contamination on soil organic matter and microarthropod communities, in particular Collembola

The effects of long-term, geogenic heavy-metal contamination on the soil zoocoenoses and decomposition processes were studied in two beech forest sites near Heidelberg, Germany. One of these was heavily contaminated with Pb, Cd, and Zn. In the data presented, the condition of the soil organic matter (SOM) and the microarthropod communities in the two sites are compared. Only negligible differences between them were noted in the litter layers. However, in the mineral horizons, the contaminated site showed an accumulation of SOM of up to 100% relative to the reference site and of humic substances up to 200%. SOM was less degraded and humic substances less polymerized than in the reference site. The initial breakdown of litter material appeared similar in both sites, with differences seeming to occur only in later stages of decomposition. Collembola community structure was highly skewed in both sites with Isotoma notabilis and Folsomia manolachei strongly dominant. The greatest site differences were noted among subdominant species living in those soil horizons with the largest differences in SOM. (C) 1998 Elsevier Science B.V.