Structural and functional organization of ant communities in secondary meadow ecosystems

Abstract

Introduction. Due to a significant biomass and diverse ecological niches, ants (Formicidae, Hymenoptera) are crucial in establishing the structure and functioning of the co-adaptive species complexes, i.e. myrmecocomplexes, to which they belong. The majority of ant species, which build their nests with visible anthills, create humpy micro-relief changing the habitats of numerous plant and animal species. The number of active ant families and the number of their nests indicate the functional power of every species in an ant community. According to the dynamics of nest numbers, it is possible to analyze the changes in the ecosystem as a whole. Materials and methods. The research territory is located in the SE suburb of Lviv on the edge of Davydiv and Holohory ridges. It includes two former agricultural sites: fallow arable land and fallow grazing land. The material was collected by the method of ant exclusion with its following conservation, laboratory analysis and determination. Anthill mapping was conducted on 200 sq. m sites. Results and discussion. The results suggest that the more structured a habitat is, the higher ant species diversity is observed: seven species were found in the fallow grazing land (Formica pratensis – dominant, F. cunicularia – subdominant, Tetramorium caespitum, Lasius niger, L. flavus, Myrmica rubra, Solenopsis fugax – all are influents). It is typical of the three influent species (L. flavus, T. caespitum, M. rubra) to distribute within the territory of a dominant’s foraging area. However, the influent ant species avoid contacting each other. The less structured habitat (fallow arable land) is presented by only two of the most adaptive species, which are in high numbers (L. niger – 95 % of the site nests, and L. flavus – only 5 % of them). Conclusions. Thus, each ant community is a system of „dominant–subdominant–influent” species, which is under permanent transformation due to anthropogenic habitat changes; only well-adapted species can stay in the community under the influence of the mentioned changes. The research on the spatial distribution of ant nests testifies to the prospects and need for the mapping method used to establish the type and level of previous anthropogenic impact on the ecosystem (grazing, ploughing, grass burning, etc.).