Surface-living invertebrates in grassland habitats were collected in pitfall traps for one year in three hayfields
and three pastures in northern Iceland. Hayfields and pastures were on three different soil types; sand, silt
and peat. Traps were renewed at weekly intervals during summer (six replicates) but at longer and variable
intervals during winter (two replicates). Collembolans were counted and grouped to families or subclasses.
During the summer season Collembola were most abundant in late summer and early autumn (second part
of July to end of August) and Isotomidae and Symphypleona dominated. Onychiuridae and Entomobryidae
culminated in spring, Hypogastruridae and Symphypleona in late summer and Istomidae in early autumn.
During summer Collembolans dominated by Onychiuridae, Isotomidae and Entomobryidae were significantly
more abundant in pastures than hayfields, indicating that hayfield cultivation (fertilization and mowing)
disturbs the natural pasture habitat. Hypogastruridae and Symphypleona were not significantly more
abundant in hayfields. Isotomidae and Symphypleona thrived significantly best in peat soil and Onychiuridae
in silt soil. The number of collected Collembolans was about nine times higher during the summer than in the
winter. During winter Entomobryidae were also more abundant in pastures than in hayfields and also more
abundant than Hypogastruridae in hayfields. In soil samples collected in September four species dominated:
the Hypogstruridae species Ceratophysella denticulata in hayfields on peat soil, the Onychiuridae species
Protaphorura bicampata on silt soil and mainly in pastures, and the Isotomidae species Isotoma caerulea on
peat soil. The fourth species, the Isotomidae Parisotoma notabilis, was not attracted by a specific environment.