The greater oak beetle has been extinct on the Swedish mainland for 50 years.
But through a program of measures, ecologists have now succeeded in re-establishing it in two places.
– If you are not particularly impressed by the fact that there are larger oaks, then you have to see it in a larger context, where we have to have functioning ecosystems, says Jonas Hedin.
With a body of five centimeters and antennae of up to ten, the greater oak beetle is one of Sweden’s largest beetles. It is also acutely threatened, red-listed and extinct in almost all of Sweden.
Ecologists from the Kalmar region and Nordens ark have succeeded in breeding new specimens in a lab and these are now placed in the nature reserve Halltorp’s meadow on Öland.
– The population is very small, so we try to keep the species. We usually plant a small percentage of what we grow here, says Jonas Hedin, ecologist at the Kalmar County Administrative Board.
Extinct on the mainland
During the last 50 years, greater oak buck has only been found in Halltorp’s paddock on Öland, but now it has been re-established in two places on the mainland. In the Björnö nature reserve outside Kalmar, success was achieved in 2022. In Tromtö in Blekinge, fresh oak bucks were discovered for the first time in May this year.
The re-establishment is the result of a 20-year action program for greater oak buck. In a collaboration between the county administrations in Kalmar and Blekinge and Nordens Ark, oak bucks have been bred and places where they can thrive have been identified.
Crucial for biodiversity
Greater oak buck begins its life as a larva inside old oaks. When fully grown, it bites through the bark to get out and mate.
The oak tree is a so-called key species, the holes they create in the bark contribute to the environment’s biological diversity. Excrement flows out of the holes and becomes food for other insects, which in turn pollinate plants and become food for birds.
– That we have to invest at least in our own future is quite obvious. Biodiversity is insurance for us humans, says Jonas Hedin.