EFFECTS OF CLEAR-CUTTING ON LITTER DECOMP OSITION AND THE DENSITY OF EARTHWORMS IN MOUNTAIN FORESTS OF SOUTHERN GERMANY

The effects of clear-cutting on species association, density and bioma ss of earthworms were investigated in the forests of the Flysch Range situated in the Tegernsee Mountains. In addition, the decomposition of litter was measured in clear-cut and in control areas. Thirteen speci es of earthworms were sampled with mean densities varying from 32 to 6 4 ind./m(2) (median). Soil-pH was correlated positively (p less than o r equal to 0.001) with abundance as well as biomass of both the minera l-soil dwellers and the deep-burrowing species Octolasion transpadanum . Furthermore, in the second year following clear-cutting the density of lumbricids decreased significantly from 48 ind./m(2) to 32 ind./m(2 ) (p less than or equal to 0.05) in comparison to the control forest. Reduction in earthworm-density was associated with reduced litter deco mposition (p less than or equal to 0.01). Decomposition rate was 37.1% in the control area compared to 31.3% in the clear-cut area. The effe cts of the litter-consumption of earthworms and their burrowing activi ty on the biological and physical soil characteristics (decomposition and waterholding capacity/saturated hydraulic conductivity respectivel y) are discussed.