value of open power line habitat in conservation of ground beetles (Coleoptera: Carabidae) associated with mires

The draining of mires for silvicultural purposes has caused one of the most dramatic changes in the landscape during the last century in Finland. To study the effects of mire drainage, carabid beetle assemblages were sampled using pitfall trapping in three different mire habitat types. Carabids were sampled from mires in their natural state, drained mires and drained mires with an open power line to see whether the cleared power line can serve as an alternative habitat for mire dependent carabids. The draining of mires greatly increases the species richness of the carabid assemblages. Yet, the conservation value of the environment has dropped following the draining, since only common and abundant forest carabids have benefited from human impact. The role of the open power line as an alternative habitat for mire specialists remains questionable. A few carabid species have, however, benefited from the open habitat of the power line. The vegetation structure had a significant effect in determining the compositions of the carabid assemblages on the studied habitat types. It seems that mire dwelling carabids cannot survive on the drained mires, unless at least some characteristics, other than the mere openness of the cleared power lines, of natural mires remain.