Arno Thomaes studies the forest habitat types and saproxylic beetles of the Habitats directive. The research concerning the forest habitat types includes the classification, status assessment, distribution, management and threats. Concerning the saproxylic beetles, the focal species are the European stag beetle (Lucanus cervus), cinnabar flat bark beetle (Cucujus cinnaberinus) and hermit beetle (Osmoderma eremita) and the research covers distribution, population structure, threats and protection, status assessment, ecology, monitoring, genetics, dispersal, morphometrics and many other aspects. Besides this, the research also covers other beetles as well as the development of new monitoring techniques including the use of detection dogs.