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Bilberry (Vaccinium myrtillus L.) is a dwarf shrub with high ecological relevance as habitat and as a food source for many animals in mountain forests of central Europe. This species benefits from conifer forests and declines with an increase of broadleaved tree species in the canopy. The ongoing large-scale conversion from conifer to broadleaved forests may significantly alter the ground vegetation, especially the dominance of a key species such as bilberry. We used morphological indicators to investigate the vitality of bilberry. The first objective was to determine whether the vitality of bilberry is negatively impacted by increasing the proportion of beech (Fagus sylvatica L.) in Norway spruce (Picea abies Karst.) forests. The vitality of bilberry was measured by its cover, height, biomass, shoot length and basal diameter. The second objective was to determine whether these changes in bilberry vitality were related to light, canopy cover, soil pH, organic layer mass and tree species. The data was collected from three study areas in the southern and central Black Forest. The bedrock consisted of gneiss and granite whereas the stands were either: pure beech, a mixture of beech and spruce or pure spruce. The stands were located adjacent to each other. On all three areas a higher vitality of bilberry was observed under spruce compared to beech. Mixed effect models show that the occurrence of spruce is the most important variable explaining the increase in bilberry biomass. Light had a small positive effect, whereas soil properties had negligible effects and were site specific. These results are a strong indication of the negative influence that beech has on bilberry in conifer dominated forests. This has to be taken into consideration when developing silvicultural approaches and should be a consideration when making plans for the preservation of habitat for species like capercaillie (Tetrao urogallus L.). This is even more important today because the recent trend in central European forestry is to increase the proportion of beech.
Chemo-communication is an important mode of interaction within ecosystem. The living organism in the ecosystem can deliver signals to conspecifics, to co-organisms, and unintentionally to their enemies, by emitting the volatile organic compounds (VOCs) to the atmosphere. There are some insect-fungi-associations displaying interesting relationships. For example, some bark beetle species (PAINE et al. 1997) introduce fungi into the conifers during the attack process. Fungi take advantage by associating with the insect in transport to new trees and passage through the bark. Insects may get advantage by feeding on fungi and overcoming the tree defence. Questions arise how fungus vectoring insects can recognize the weakness of defense mechanism in the case to introduce the fungus to the host tree and successfully overcome the remaining defence mechanisms. The interspecific communication among insects, fungi and host trees are not completely clarified, but there was the evidence that a number of forest scolytids including species in the genera Scolytus, Dendroctonus, Hylurgops, Trypodendron and Tomicus can be attracted to the host volatile compounds (BYERS 1995).
Laufkäfer werden in ökologischen Studien zur Lebensraumbewertung sehr häufig als Bioindikatoren hinzugezogen (PLATEN & KOWARIK 1995, PLATNER et al. 1996, POSPISCHIL 1981), denn ihre Ökologie und die daraus resultierenden ökologischen Ansprüche sind durch zahlreiche Studien eingehend untersucht (u.a. BAEHR 1980, LINDROTH 1945, THIELE 1977). Unterschiede in der Artengemeinschaft bzw. Änderungen in der Abundanz der Carabiden lassen Rückschlüsse über Habitatqualität, Standortsfaktoren, Minimalareal- Fragen, Habitattradition und Vernetzung von Lebensräumen zu. Diese Tatsachen wurden ausgenutzt, um die Bestandstradition und die Naturnähe der Bestockung der Probeflächen zu untersuchen. Diese sind weitgehend naturnahe Wälder im südbayerischen Tertiärhügelland, einem insgesamt wenig naturnahen, forstlich durch Fichtenforste geprägten Landschaftsraum.