Habitat continuity matters: Ancient woodlands tend to have higher biomass and catching rate of dung beetles, mainly driven by one large species

Abstract

Ancient woodlands differ from recent woodlands by numerous abiotic and biotic factors, including soil properties. Several animal species are more abundant in ancient than in recent woodlands, but this has been only rarely tested for saprophagous taxa and not at all for dung beetles, which are common in temperate woodlands. Beside habitat continuity, tree age can have also an effect on woodland inhabiting animals, especially on saprophagous taxa. To analyze the effects of both habitat continuity and tree age we studied dung beetles in a continuous north-west German woodland with baited pitfall traps on basis of a factorial design. We compared species diversity (Shannon-Wiener-Index and Pielou's Evenness), catching rates, biomass and community composition of dung beetles. With only 18 recorded species from 20 study plots, dung beetle communities were species-poor and dominated by one large tunnelling species. The main result is that catching rate and biomass of dung beetles were higher in ancient woodlands, which was due to the particularly high catching rate of the most dominant tunnelling species and one dweller species. Tree age alone had a minor impact, but affects significantly one rare species. Diverging habitat quality of ancient and recent woodlands likely explains differences in the communities of dung beetles in woodlands of different habitat continuity. Old trees in recent woodlands could not compensate for habitat continuity of ancient woodlands.