Lumbricidae communities in several years old midfield shelterbelt [Turew Region, Western Poland]

Species composition, density and biomass of Lumbricidae were studied in soils of a several years old midfield shelterbelt, an adjacent arable field (maize, wheat) and an ecotone situated between both ecosystems in two years (1999, 2000) in spring, summer and autumn. The lowest density and biomass of Lumbricidae was found in the field. The only species present there was Aporrectodea caliginosa: mean density 0.9 ind m⁻² and biomass 0.7 g m⁻². Three species were found in soils of the shelterbelt and the ecotone - A. caliginosa, Dendrobaena octaedra and Lumbricus terrestris. Two species dominated in biomass and density; L. terrestris occurred sporadically and its biomass and density were low. The average density and biomass in soils noted in 1999 were 58 ind m⁻² and 15 g m⁻², respective values for the ecotone were 73 ind m⁻² and 24 g m⁻². In the next year a nearly twofold increase of density (the shelterbelt - 144 ind m⁻², ecotone - 159 ind m⁻² was noted and similar increase of biomass in shelterbelt soils (31 g m⁻²). A. caliginosa, depending on site and time, contributed to 35-76% to the density and in 68-93% to the biomass of the community, D. octaedra - in 22-64% and 7-30%, respectively. Apart from biomass in the first study year, no significant differences between the shelterbelt and the ecotone were found in both density and biomass of the earthworm community.