Habitat preferences of Ceruchus chrysomelinus, an endangered relict beetle of the natural Central European montane forests

Abstract

Abstract Montane forests represent the majority of natural forests remaining in Europe. Their quality can be indicated by the occurrence of saproxylic invertebrates. Information on the habitat requirements of threatened species inhabiting such forests is a necessary prerequisite for qualified management decisions. Ceruchus chrysomelinus (Lucanidae) is an endangered relict species of European montane forests, but its ecology has been poorly studied to date. Hence, the habitat requirements of the species were analysed using fallen log sampling at four localities in the Hrubý Jeseník Mts., Czech Republic. The main factors affecting the beetle's occurrence were decay stage, rot type, diameter, and humidity of the log. We found that C. chrysomelinus developed in humid, medium‐to‐strongly decayed logs, with brown rot penetrated deep into the wood. Spatial analysis showed random distribution of logs colonised by C. chrysomelinus, which is likely a result of the continual long‐term presence of the species at the localities. C. chrysomelinus can thrive only in forests with a continuously sufficient supply of logs with specific features. Since the majority of European forests suffer from diminished spatio‐temporal heterogeneity, populations of C. chrysomelinus need to be supported by repetitive felling and leaving suitable trees (within a radius of tens to a hundred metres from colonised logs). In well‐preserved natural forests, just leaving them unmanaged might be an appropriate conservation strategy. C. chrysomelinus is one of the relicts indicating European natural forests; successful conservation of its habitat may then open an umbrella for many other saproxylic organisms.