Forest edges - centres of biodiversity
In a research project on the contribution of forest ecotone structures to regional biodiversity, species variety was determined at five differently structured forest edges and, for comparison, at 50 m inside the forest. Arthropods were collected with standardized faunistic sampling methods from March through November. Traps were installed along transects reaching horizontally from the open cultivated land into the forest and vertically from the ground up to the tree tops. The highest numbers of species were collected in the herbaceous fringes. By comparison, the traps located deepest inside the forest yielded only 29-49% of the number of species in the herbaceous fringes. At the forest edges, species numbers were found to decrease with increasing height, while inside the forest species numbers peaked in the canopy. However, the canopy yielded markedly fewer species than the forest edges. Overall species numbers at forest edges correlated positively with a vegetation-based score of these habitats. Sloping, structurally rich forest edges contained about a third more arthropod species than steep forest edges. Our results support the hypothesis that the contribution to regional biodiversity of managed forests in Central Europe is determined to a large extent by the structure of their periphery.