Xylobiont Coleopterans

Can forests of the Carpathians be a reference point for the virgin forests of the Central Europe? The proof for this is represented by xylobiont Coleopterans Over recent years many German experts specialising in forestry have visited forests in Romania and Ukraine. On these occasions, they discussed fundamental problems related to virgin forests: the dynamic of rejuvenation of large areas of deciduous forests in the presence of the three species of big carnivorous animals (the wolf, the bear and the lynx) is one of the first important findings.We remember the fact that for more than 100 years these forests have been visited by botanists, zoologists and sylviculturists, among which Ganglbauer 1896, Adamovic 1898, Petri 1912 and Roth 1912.Recently, on the occasion of the delimitation of some national parks, several German teams specialising in forestry, zoology and botany made investigations. The researchers visited the Cerna-Domogled National Park in the proximity of Baile Herculane, as well as the future national park Defileul Jiului, which is under the jurisdiction of the Forestry Central Office of Targu Jiu. The investigations were not very thorough, since they took only a few days, but they revealed a surprising complexity with regard to xylobiont coleopterans from deciduous forests. You must know where to look…This notion is widely spread among the specialists in forestry, wherever extinct species of insects are concerned. If specialists looked in the appropriate places, they would find many species which are currently believed to be extinct in Germany. But concrete results look totally different: 51 species of coleopterans whose existence depends on wood are supposed to be extinct, although thorough investigations have been carried out over the last twenty years. Even if sometimes one of the respective species is found, the general situation remains the same, the number of extinct species remains the same. Many of the 212 endangered species have been mentioned in Germany for dozens of years. For example: an impressive survey of the extinct species of Rhysodes sulcatus F. in Western Europe was made by Speight (1989). The disappearance of the species was documented with the help of fossil samples from peat bogs. Thus, in the year 1000 B.C., the species existed in England, but it disappeared in France in the year 1800, and in Germany in the year 1900. Nowadays, this particular species can be found only in the virgin forests in eastern Europe, where it survived. This wave of extinction from west to east is representative for many species of coleopterans whose existence depends on the presence of wood, as do many other species from the animal kingdom. (Reichholf 1996). Can the Carpathians bear comparison?This is a justified question if we wish to use the Carpathians as a reference point for the forests of Germany. For the coleopterans whose existence depends on the presence of wood in the Romanian Carpathians, the results are surprising. Although the Carpathians are at a 1000 kilometer distance from Germany, the inventory of species corresponds to that of Germany. Only 6% of the species are south-east-European fauna elements and therefore they are not present in Germany. Such a species, spread throughout southern Europe and in the south of Central Europe, which does not exist in Germany, is Morimus funereus Muls. It lives in the Romanian beech forests in association with Rosalta alpina L. Relict species from virgin forests, indicators for balanced deciduous forests The relict species linked to ancestral forest structures were chased away through forest 'cultivation'. Although intensive research was carried out in the protected forests of Bavaria, only 20 species were found, in 9 different locations. More often than not, these were isolated individuals or very small numbers. All the locations are in reservations or rests of woods which now serve as pastures. On three different occasions, while traveling to the Romanian Southern Carpathians, specialists found 25 relict species of larger numbers among which were several species which were considered to be extinct in Germany. It seems there are no effects of isolation for these insects in the wide areas of forests in the Carpathians. Species of the Fauna and Flora Directive The European Union selected 12 species of xylobiont coleopterans for the Fauna and Flora Directive (annex 2). Protection areas are delimited for these species, which are monitored and if necessary economic projects are given up or become of a secondary importance. In Germany, these species still exist in small and isolated biotopes or in very low density. Hardly ever are there more than two of these species in the same place. What is the situation in Romania? The findings in Valea Jiului went beyond any expectations: on a surface of only 6 ha the following species were identified: Cerambyx cerdo L., Rosalia alpine L., Cucujus cinnabarinus Scop., Lucanus cervus L (stag beetle), Rhysodes sulcatus F., Morimus Funereus Muls. and Osmoderma ermita Scop., some of which in incredible densities. In the Cerna-Domogled National Park we managed to identify the species Buprestis splendens F. There are also two more species within the directive. In the forests of the Southern Carpathians there are at least 10 of the 12 species of coleopterans listed within the directive. The Carpathian forests also suggest where we should look for the origin of relict species; not in the grazing forests, which have been artificially opened, but in virgin forests. It is there that they can live and can survive, in the absence of big herbivorous animals. Why are Romanian beech forests so rich in species?The richness of the species and the central European complete biocenose of coleopterans whose existence depends on wood have several explanations: 1. The beech re-appeared in the Carpathians after the last ice age, 5000 years earlier than in the region of Bavaria. Through a long co-evolution, several species of coleopterans were able to adapt to the beech and thus to enlarge their ecological amplitude. In Germany, these species are known to be associated only with evergreen trees and poplars. 2. Large forests have a diversity of biocenoses with an ancestral composition of species. Even isolated trees from deciduous forests such as the fir-tree or the pine shelter species of coleopterans depending on this wood species (stenecological species). In Germany, the variety was ignored through homogenous plantations; thus, the species of trees and the corresponding fauna were reduced. Segregation became irreversible and the traditional biotope was broken. This process remained irreversible, in spite of the fact that certain species of trees were re-planted. The situation is different in the Carpathians. In Valea Jiului the beech appears on the river side 300 meters away and goes as far up as 1400 m. Several species can appear in the same place at once, depending on the area. In the proximity of the river, the dominating species are the alder tree, the poplar, the ash tree, the lime and the hornbeam, and in rocky places, the birch tree and the pine. The forests in which the pine dominates are in less rugged places with southern exposure. After an area populated almost exclusively with beeches, in higher lands the fir-tree and the spruce fir appear. This combination of natural forest allows an exchange of fauna from a tree species to another. 3. Of course, the Carpathians underwent forest exploitation, but the essential structures remained unchanged. Traditional biotopes stayed the same. 4. In the Southern Carpathians, there was no essential fragmentation of forest surfaces through massive deforestation or through replacement of deciduous forests with evergreen forests. 5. Agricultural surfaces are sprinkled here and there with isolated trees or groups of trees, old trees along water shores and shrubs. The presence of species of relict coleopterans in these old trees from the ruderalized landscape shows how important they are for the forest network.