Forests cover around one third of all terrestrial area and provide resources, shelter, and habitat for many species. In particular, this includes managed forests in Europe which are degraded and lack old-growth elements, such as dead wood among other things important for habitat provision. Saproxylic beetles are relying on dead wood during at least one stage of their life cycle and are therefore especially sensitive to forest management. With more than 1400 species recorded in Germany, sampling and identification is both time and cost intensive. Genetic identification (e.g. metabarcoding) is a relatively new method which reduces time forhandling and identification. Environmental DNA metabarcoding (eDNA) has the additional benefit of sampling the substrate rather than specimens themselves, making it a non-invasive method while also decreasing sampling time. In order to improve saproxylic beetle monitoring and collection methods, we tested the application of eDNA metabarcoding on dead wood substrate. In a mesocosm experiment, we were able to detect multiple saproxylic beetle species, but only when targeting small DNA sequences from fresh exit holes, where beetles were recently active. We therefore assumed a high enzymatic activity in dead wood substrate which results in fast DNA degradation, making wide application rather difficult. Nevertheless, in order to formulate management recommendations for research and conservation purposes, collection is required to understand the ecology of saproxylic beetles and the effects of forest management.
