Abstract. Pitfall trapping is an approved self-sampling method for capturing epigeal arthropods for ecological and faunistic studies. Capture efficiency of pitfall traps may be affected by external factors and the design of the trap. Pitfall traps set in forests are usually protected with covers or wire grids, but the effect of these constructions on sampling efficiency as well as their practicability and necessity have so far received little attention. During the present study pitfall traps of four different designs (covers, wire grids, litter exclosure, open) were tested in terms of their efficiency in capturing ground-dwelling arthropods (Acari, Araneae, Carabidae, Formicidae, Isopoda, Myriapoda, Opiliones) in order to gain a better understanding of the applicability and reliability of pitfall traps in forests. The study was carried out in an oak-beech forest in Northwest Germany using a total of 40 pitfall traps (ten replicates per trap design). Generalised linear models indicated no significant differences in arthropods counts among catches of pitfall traps of the four different designs, except for woodlice. Ordination analyses (NMDS) and MANOVA revealed no significant differences in spider and carabid beetle species compositions of the catches. In contrast, for both these taxa there were significant differences in the body sizes of the individuals caught. We conclude that the catches of pitfall traps are little affected by their design. Furthermore, the litter layer and litter input have no effect on the capture efficiency and thus there seems to be no need to protect pitfall traps with covers or wire grids in litter rich forest habitats.

Spinnen suchen im Winter zumeist geschützte und frostsichere Strukturen auf. Um zu testen, inwieweit die Habitatstruktur die winteraktiven Spinnen beeinflusst, wurden sechs Habitattypen mit jeweils unterschiedlicher Strukturvielfalt (offene Sandflächen, Halbtrockenrasen, Calluna- Heide, Grünland, Wiesen, Laubwald) hinsichtlich ihrer Diversität und Artenzusammensetzung miteinander verglichen. Dazu wurden 31 Probeflächen mittels Bodenfallen in den Wintern 2008 und 2009 befangen. Insgesamt wurden 54 Spinnenarten (2053 adulte Individuen) erfasst, wobei Linyphiidae dominant vertreten waren. Es konnten keine signifikanten Unterschiede bezüglich der Arten- und Individuenzahlen festgestellt werden. Korrelationsanalysen zeigten jedoch einen positiven Zusammenhang zwischen der Krautschichtstruktur und den Arten- und Individuenzahlen. Die multivariaten Analysen ergaben jeweils charakteristische Artenzusammensetzungen in den unterschiedlichen Habitattypen.