Long-term dynamics and spatial distribution of stable and labile components in ground beetle communities (Coleoptera: Carabidae) in a mosaic of flood-plain meadows

Abstract

Abstract. Background and purpose: Long-term changes in the community structure of ground beetles were surveyed in nine flood-plain meadows of the Oka River valley (Ryazan Region, Russia) using the concept of stable-labile components. Such approach contradicts with the traditional estimation of the community structure, and there are only a few similar studies now. Material and methods: Based on inundation time, all model habitats were divided into three groups: dry, short-term flooded, and long time flooded meadows. Beetles were trapped from mid-April to late September 2006 and from early April to late October in 2007 and 2008 using pitfall traps. All captured beetles were dissected and the conditions of their gonads were evaluated. Results and conclusions: Altogether, 142 species from 50 genera were recorded. In terms of abundance, 84% of all specimens belonged to 22 species (15.5% of the total species diversity). However, neither in all years nor in all study habitats the local populations of dominant species are characterized by a complete demographic structure. On the contrary, 49 species were residents, but only from three to 27 of them completed their life cycles at least in one habitat. In total, the labile component usually had a higher species diversity, but the stable component was more abundant. Large-scale migrations were typical solely of stenotopic species that inhabit only few meadow types. Eurytopic species were easy to redistribute in a limited area and occupied all available habitats. In some species, not only migrations, but also changes in life cycles from annual to biennial ensured the survival of their local populations.