Habitat of the Heldbock: Where the Riederwald tunnel is to be built, the larvae of the beetle, which was threatened with extinction, live in old oak trees.
Image: Domenic Driessen

For the opponents of the Riederwald tunnel in Frankfurt, he appears at exactly the right time: the strictly protected Heldbock. But is the beetle, which is formally a protected species, still a reason to stop construction projects?

Dhe European hamster has the potential to stop construction projects. In the Rhine-Main area, too, there are only very few specimens of this strictly protected and endangered species. And so its occurrence often means the end of new construction plans, such as in the Frankfurt district of Sindlingen, where around 2000 new apartments were originally supposed to be built. In the Fechenheim Forest, where the trees on an area of around three hectares are expected to be felled in November for the construction of the Riederwald Tunnel, opponents of the motorway project have now discovered the Heldbock. It is also a strictly protected species.

The BUND Frankfurt is therefore calling for a moratorium on the planned clearing. The faction of the left in the Roman joins the demand. With its head and trunk five centimeters long, plus antennae that are up to eleven centimeters long, the Heldbock is one of the largest beetles in Central Europe. Its habitat is oak trees, which is why it is also called the large oak buck. The key is that its larvae, which take at least three years to develop, dig deep tunnels in weakened trees. The larvae practically live in the tree.

“He is a beneficiary of climate change”

In the past, the heldbock was therefore considered a forest pest and was fought against. Eventually it damages the wood and the colonized trunks are no longer suitable for sale. Because of the fight, the beetle had become rare. The EU’s Fauna-Flora-Habitat Directive therefore stipulates that the remaining populations should be preserved. As a result, the Federal Nature Conservation Act lists the Heldbock as one of the “strictly protected species”. That means: Each individual animal has to be protected as well as the habitat of the species. The law speaks of so-called habitat protection, so that reproduction is secured and the animals can find “resting places”.

Is the occurrence of the beetle in the Fechenheim forest the end of the Riederwald tunnel? The Heldbock is a protected species “that we now deal with very routinely,” says Volker Rothenburger, head of the Lower Nature Conservation Authority in Frankfurt. Because the Heldbock is no longer as rare as it was years ago. “He is a beneficiary of climate change,” says Rothenburger. The Heldbock loves it warm, prefers sparse forests and sunlit oak trunks for its larvae. Traditionally, it inhabits old, gradually dying trees, in any case those that are no longer really sap and vigor. “There are no bucks and larvae of bucks in vital trees.”

Found on old and damaged oak trees: the held beetle, one of the largest beetles in Central Europe, also lives in the Fechenheim forest.

Dying oak trees damaged by heat and drought have been plentiful in Frankfurt and the entire lower Main plain since the extreme summer of 2018 at the latest. That’s why there are some construction projects in Frankfurt where the experts came across oak trees in which the Heldbock was at home, says Rothenburger. For example, with the construction of residential buildings on the north-eastern part of the Rebstock site and with the construction of the academy of the German Football Association, which opened at the end of June on the site of the former racecourse in Sachsenhausen.