Good news for fans of special, very rare beetles: the populations of the ground beetle or Carabus variolosus nodulosus, which is the scientific name of the species, are stable in Bavaria. This has now been revealed by regular monitoring by the State Institute for Forestry and Forestry (LWF). The ground beetle, which can grow to a size of three centimeters, is deep black and its body sometimes has a faint shine. The forest dweller can be easily recognized by the large, pit-like depressions on the elytra and pronotum. He gets his name from them.
The ground beetle is only found in Central and Eastern Europe worldwide; in Germany, the strictly protected species has only been documented in Bavaria, with the exception of one location. In around 80 places in the triangle between western Upper Bavaria, eastern Lower Bavaria and the border with the Czech Republic and Austria. Lives here Carabus variolosus nodulosu in largely natural deciduous forests with moors and forest streams. The beetles cannot fly. That’s why they hardly spread even under favorable conditions.
In forest streams and moor pools, the ground beetle hunts snails, small crustaceans, insects and their larvae, but also tadpoles and even small fish. To dive, it creates a supply of air under its wing coverts. Dead trees and moss cushions serve as hiding places and overwintering places. Most deposits are very small and isolated from each other, so that no exchange between the stocks can take place.
“Bavaria has a very special responsibility for the preservation of the ground beetle,” says LWF President Peter Pröbstle. “Especially since it is an important indicator of the ecological status of our forest streams and forest springs.” And it is representative of many other animal, plant and fungal species that occur in the same, increasingly rare habitat. Few of these species are as prominent as the dipper. The vast majority, including round worms and snails, are so tiny and inconspicuous that only experts know about them.
According to current monitoring, only two percent of the Bavarian mine ground beetle occurrences are in excellent condition. But at least 56 percent were classified as good. In 42 percent of the populations, the habitat is disturbed, be it because it is too small, the respective stream is in poor condition or there are not enough dead trees as winter quarters for the beetles. The results of the monitoring will now be reported to the EU Commission via the Federal Agency for Nature Conservation, where they will be combined with data from other member states.
Meanwhile, Pröbstle appeals to the owners of forests with ground beetles to work towards their preservation. A few simple measures often help. Examples include cordoning off sensitive areas during felling operations, avoiding storing wood on damp forest floors or leaving dead trees on the banks of forest streams.