Habitat predictability and the occurrence of wood beetles in old-growth beech forests

We sampled the wood beetle fauna in 1) living hollow, 2) standing dead and 3) downed dead beech Fagus sylvatica logs in fragmented old-growth forests in southern Sweden. In nearly primaeval stands, species richness was similar in the three types of microhabitat, but in previously (50-100 yr ago) managed stands species richness was lower in living hollow trees. The number of red-listed beetle species per sample was higher in living hollow beeches in nearly primaeval stands than in formerly managed stands, but there was no difference in downed dead beeches. This agrees with our expectation, based on the relative stability of the microhabitats, that species living in hollow trees would have a lower dispersal propensity than those that depend on dead, downed logs. Among 55 red-listed species found, 69% had a higher frequency in nearly primaeval stands than in previously managed stands. For 22 endangered plus vulnerable species the figure was 77%. Most red-listed species had occurrence frequencies of 5%, or less.