The Effect of Soil Type and Soil Moisture on Earthworm Communities

Twenty four study areas of three most widespread soil types (pebble rendzinas, typical brown soils and pseudopodzolic soils) all over Estonia were selected. In each group of soil type, eight fields were selected for studies in 2003–2004. The mean abundance of earthworm communities was the highest in pseudopodzolic soils (107.11±22.4 individuals per m) and lower in pebble rendzinas (47.94±11.25 individuals per m) and typical brown soils (72.97±15.13 individuals per m). The number of earthworm species in a community was 1–6. In all fields 7 species of earthworms were found, also a few individuals of 3 species. Soil moisture influences the abundance of earthworm communities more than soil type whereas ecological and specific structures are less influenced by soil moisture. Pebble rendzinas are suitable habitats for earthworms but periodical drying out decreases the abundance of earthworms. In pseudopodzolic soils the abundance is higher if there are optimal moisture conditions, due to increasing abundance of ecologically tolerant endogeic species. In typical brown soils the diversity and number of juvenile individuals is high which indicates suitable conditions for habitat in this type of soil.