Habitat Selection of Lumbricids in Iceland

Abstract

The distribution of lumbricids in different biotopes in Iceland was studied during 1972-74. Man-made and biotopes were distinguished and subdivided according to vegetation and intensity of cultivation. The most common lumbricids were Dendrobaena octaedra (Sav.), D. rubida (Sav.), and Lumbricus rubellus Hoffm. They were, together with Allolobophora caliginosa (Sav.) and Eiseniella tetraedra (Sav.), spontaneously dispersed. The distribution of L. terrestris L., Octolasion cyaneum (Sav.), and A. rosea (Sav.) was strongly associated with man and these species have not so far been found in natural biotopes. The only factor which could be correlated with the occurrence and density of lumbricids in natural biotopes was the luxuriance of the vegetation. In poor biotopes the lumbricid biomass was low and Dendrobaena spp. were dominant and constant. In meadow biotopes biomass and density were high and L. rubellus and A. caliginosa were constant and usually dominant. These two species were also common in man-made biotopes. Except for hayfields, man-made biotopes usually had high biomass and density. Hayfields were characterized by a low number of species and a varying species complex. No trend in the lumbricid distribution was discernible in this biotope.