Abstrakt
Abstract
The ability to locate and colonise ephemeral deadwood resources is crucial to saproxylic beetle assemblages. Saproxylic beetles locate suitable substrates mainly through visual cues and via olfactory cues emitted by deadwood, other insects and fungi.
For the conservation of saproxylic beetles, it is essential to understand which abiotic and biotic factors most significantly influence their habitat requirements when locating suitable substrates.
In a field experiment, in sunny and shaded plots, we exposed 400 bundles of freshly cut deadwood, each consisting of three logs with a combination of different tree species and treatments (i.e., fungi inoculation), mimicking biotic interactions. We sampled arriving saproxylic beetles via sticky traps directly applied on deadwood to evaluate the effect of sun exposure and the biotic interactions on arriving saproxylic beetles.
We found higher species numbers and abundance of saproxylic beetles under shaded than sunny conditions, but we detected no effect on the standardised number of species (diversity). However, we observed a shift in species diversity from sunny to shaded conditions from early to late season. Beetle assemblages differ between shaded and sun‐exposed deadwood. Treatments (fungi inoculation, sterilisation and burning) did not affect the arriving saproxylic beetles.
Our results suggest that saproxylic beetles‘ attraction to freshly cut deadwood is mainly driven by sun exposure rather than biotic interactions, despite assumed close associations between beetles and fungi. To protect the full spectrum of saproxylic beetle species, we recommend maintaining sunny and shaded areas, as each provides unique habitats supporting different assemblages.