According to the promising results of restoration studies conducted by the Finnish Forest Research Institute (Metla), the diversity of beetle species is increasing in Pahamaailma located in north-eastern Finland in the Hossa district of Suomussalmi. Controlled burning on restoration sites caused a distinct increase in the numbers of beetle species. The numbers of individual beetles increased five-fold, whereas in areas where no restoration procedures were carried out the numbers of species and individual beetles remained almost unchanged. The burned restoration sites attracted five endangered species onto them, whereas the control sites attracted none.
The most significant endangered species that was observed in the area after the fire was Phryganophilus ruficollis, an extremely endangered saproxylic beetle, found only in a few locations in Finland . This imposing black and red beetle lives on dead broadleaved trees, possibly also on spruce, damaged by fire. Black fire beetles (Melanophila acuminata) arrived on the site immediately after the fire, because their extremely sensitive sensors can detect smoke and infrared radiation and therefore sense a forest fire from a distance. The black fire beetle has become rare as the number of natural fires has decreased. It is classified as needing further attention at the national level (NT, near threatened). Another endangered (EN) species, a flat bug Aradus laeviuscula, which thrives in burnt forests appeared at the test sites soon after the fires. It was thought to be extinct in Finland , but since the 90s it has been found in fire areas in eastern Finland .
The aim of restoration is to restore natural forests to their typical structure and functions. Actions are directed at forests of protected areas where the natural state has been weakened due to commercial use of the forests. The aim of controlled burning is to restore suitable living conditions especially to species that are dependent on burnt wood. Burnt wood supports threatened beetle species that use either decayed wood or fungi growing on it as nourishment.
The results are part of an ongoing research project at Metla. The project investigates the impacts of different restoration methods on biodiversity and structure of forests and mires in northern Finland. Corresponding beetle studies are also conducted by Metla in the Natura 2000 areas in Malahvia and Elimyssalo in Kuhmo. In all research locations, follow-up studies are being continued for several years. This is to find out how long the fire-dependent beetle species remain in the fire area after the fire. It also helps to assess how often restoration fires should be realized to ensure that threatened or near-threathened species can survive in natural conditions in Finland .
The research conducted in Pahamaailma and Elimyssalo is part of the GreenBelt LIFE project funded by the EU and directed by the Metsähallitus Natural Heritage Services, Ostrobothnia-Kainuu. The aim of the project is to safeguard the favourable conservation status of thirteen Natura 2000 sites in the Koillismaa-Kainuu GreenBelt area in eastern Finland. The studies in Malahvia are part of a project funded by Metsähallitus Ostrobothnia, Forestry.