Mayen basalt mines (Mayener Grubenfeld)
The Mayener Grubenfeld project takes in one of the biggest bat colonies in Central Europe. In a core area of only 15 ha, between 30,000 and 50,000 bats are thought to live in an extensive system of sometimes hard-to-reach underground passages making up a former basalt mine. The project aims to conserve and improve this habitat for sixteen mostly strictly protected bat species. These include greater mouse-eared bat, barbastelle bat, Bechstein’s bat and pond bat. Conservation measures are planned to safeguard the bat populations together with the habitats where they live and hunt. After comprehensive surveying, failing props will be repaired, loose roof blocks secured, entrances barred and made safe, and any hazardous surface openings covered over.
The bats are tagged and fitted with transmitters to trace how the various species frequent different areas at different stages of their life cycle. This involves identifying where bats enter the underground system and any links to neighbouring winter quarters at Mendig. Flight routes are also investigated to show how nearby valleys and areas of closed woodland are connected to nursery roosts.
A sustainable tourism plan aims to coordinate nature conservation needs with tourism interests in what is also an important cultural history site. Key emphasis is placed on the relationship between mining and bat ecology. Activity in the underground passages is shown on video so that people can see the importance of the passageways as habitats while not disturbing the bats with guided tours.