Entwicklung der Laufkäferfauna (Coleoptera: Carabidae) einer Kurzumtriebsplantage über einen Zeitraum von 9 Jahren

Abstract

In order to evaluate the importance of short-rotation coppice (SRC) as habitat for ground beetles, a SRC with stands of different tree species (poplar, willow, rowan) in the municipality of Schapen (NW-Germany) was investigated during several years and different rotation-phases using pitfall traps. Regardless of the plantation-age, the cultivated tree species and the rotation-phase, the ground beetle fauna of the surveyed SRC was dominated by widespread and common generalists. Species of conservation concern (exclusively xerothermophilic species) were found only sporadically and had their main occurrence in the two years following the establishment of the plantation. During this phase, Harpalus griseus, a rare and threatened species in Lower Saxony, was detected in large numbers. After 8 and 9 years respectively, species numbers as well as the number of specimens on the entire SRC and within its different stands were considerably lower than in the early establishment phase. The partial harvest of the poplar and willow stands caused a significant change in ground beetle communities and a strong increase in the activity of openland species. However, openland generalists were the main beneficiaries, while pioneer species like Harpalus griseus occurred only sporadically. Woodland species were found only rarely even in the 9th year after establishment. We conclude that the conservational value of SRC as habitat for ground beetles is generally limited, decreases with increasing plantation-age and that a mosaic of different tree stands, rotation-phases and headlands is not sufficient to promote pioneer species of conservation concern. In order to provide permanently suitable conditions for these species, additional measures extending beyond the regular management of the plantations are required. These should aim at the creation of sun-exposed ruderal habitats with a patchy herb layer and high proportions of bare ground within accompanying structures of SRC like headlands or rides.