Habitat-binding and coexistence of carabid beetles in a glacier retreat zone in the Zillertal Alps

Summary

The spatial and temporal distributions of carabid beetles in a glacier retreat zone in the Zillertal Alps (2100 m a.s.l.) were investigated during three summers. Within the carabid assemblage of the research area six species of the genus Nebria dominated in numbers. The investigation of their habitat-binding is the focus of this study. Each of the six Nebria species exhibited peak activity in a distinct area within the glacier retreat zone. Two ripicolous species showed different diel activity patterns from those Nebria species which had their main activity during the night and which had preferred habitats with balanced microclimatic conditions. Laboratory experiments showed that the ripicolous species preferred significantly higher temperatures and survived low humidity conditions for longer than the other species studied. Two morphological adaptations were compared: the dorso-ventral flattening of the body and the difference in the development of the wings. The results show that the six Nebria species differ considerably in their habitat-affinity and behaviour in relation to the conditions of the preferred habitats.