Habitat characteristics of the endangered flightless beetle 'Dorcadion fuliginator' (Coleoptera, Cerambycidae) : implications for conservation

Betr. den Erdbockkäfer in Basel Habitat destruction and degradation are the major causes for the decline of the endangered grass-feeding flightless beetle Dorcadion fuliginator in Central Europe. We examined habitat characteristics at 19 localities which still support abundant D. fuliginator populations in the southern part of the Upper Rhine valley (border region of Switzerland, Germany and France) to obtain basic information for the management of deteriorating habitats with declining beetle populations. Populations of D. fuliginator were found in different types of grassland on south, south-west and south-east facing slopes and flat ground. Correspondence analysis showed that plant communities of D. fuliginator localities overlap widely with fertilized, dry hay meadows (phyto-sociologically defined as dry type of the Arrhenatheretum community) and to a minor extent with traditionally extensively cultivated dry grasslands (Xerobrometum and Teucrio-Mesobrometum communities). Average indicator scores of the plant communities characterize the habitat of D. fuliginator as fairly light-exposed and warm, but with relatively large ranges in humidity and nutrient content. The results of a 16-year study on the timing of emergence of the first beetles in a population provided further evidence for the high temperature requirements of D. fuliginator. Proposed conservation measures include traditional cultivation of the present secondary, man-made D. fuliginator habitats, introduction of beetles to suitable motorway embankments as well as large-scale measures allowing natural dynamics in the flood plain along the river Rhine, the presumably primordial habitat of this highly endangered beetle.