Open Access

Yvonne Mayer, Stefan Müller-Kroehling, Roland Gerstmeier

• 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.
• The role of isolated near natural broadleaved forests in a landscape dominated by manmade coniferous plantations was investigated using ground beetles (Coleoptera: Carabidae) as indicator species. Natural beech and ravine forests as well as near-natural secondary oak forests, and a pure spruce stand were researched using pitfall traps. The results were ordinated using CCA including 76 additional sites in similar forest associations. The carabid faunas of these associations group together rather well. Wet forests are most distinct, including natural oak-hornbeam forests and wet ravine forests. Dry ravine forests on calcareous slopes overlap with beech forests on calcareous sites to a certain degree, while acidic beech forests are distinct. The investigated isolated sites do not group with the natural reference sites well, the main reason being „size of forest“ and „size of broadleaved forest“, according to the CCA. These factors are to blame for an apparent loss of species that could be expected for these sites according to data from similar sites under different circumstances. Especially one investigation area with only about 5 hectares of completely isolated forest and a historical record of large-scale deforestation (for use as a vineyard and as a coppice-with-standards stand) is deprived of many species. In the other investigated area, Carabus purpurascens, absent from the entire tertiary hill land of southern Bavaria, was rediscovered after approximately 100 years in an oak forest. In this site, circumstances are apparently better, albeit not good, again due largely to habitat fragmentation, though not habitat tradition. The species lost on these sites are foremost stenotopic forest species with preference to broadleaved forests, species with a montane distribution and large species (several species of the genus Carabus) with accordingly large requirements for contiguous habitat. The results stress the importance of the protection of forests with a habitat tradition on a sufficient area.