APHIDS UNDER STRESS. SPECIES GROUPS AND ECOLOGICAL FUNCTIONAL GROUPS OF APHIDS DEFINE HEAVY METAL GRASSLANDS OF CENTRAL EUROPE

Abstract

Interest in trace metals and the environmental effects of their deposition significantly increased recently. Ecological communities formed on soils with a high concentration of heavy metals are characterised by a particular composition of plants and invertebrates in response to unfavourable physical and chemical conditions and under a strong selective pressure. Calaminarian grasslands as well as other dry grasslands are fragile habitats, very rare in Central Europe; such areas are often protected within nature reserves. This paper is the first comprehensive study of aphids (Insecta: Hemiptera: Aphidomorpha) of the metalliferous areas in Central Europe. It helped to describe the species diversity of aphid communities related to the plants of heavy metal grasslands, define the level of relationships between aphids and plants of heavy metal habitats and determine diagnostic aphid species for assemblages forming in such post-industrial landscapes. On the basis of ecological groups determined for aphids, also the number and percent of the species which form them and their ratios structure aphid communities and their condition was defined. An elevated heavy metal content in the soil does not limit the species richness of such an aphid community in comparison with those of other dry grasslands. However, these aphid communities possess specific features resulting from the mixture of species arriving from dry calcareous and sandy grasslands. The concept of ecological functional groups for analysis of aphid communities is introduced. Such an approach is useful for describing aphid communities in time and the directions of their changes, thus helping to monitor successive changes and the habitat state