Effect of extensification of coppice management on Central European ant assemblages (Hymenoptera: Formicidae)

The impact of extensification of coppice management on ant assemblages was studied by comparing two sites of grey alder floodplain coppices in eastern Austria in 1972 and 2001. In 1972, the two sites were managed similarly and were of similar structure. While one site was constantly managed until 2001 and had regained a high crown closure in 200 1, the other was extensified (prolongation of rotation period and neglect of fencing against game) and had a low crown closure in 2001. Based on knowledge of the ecology of Central European ant species and of Central European ant assemblages, the hypothesis is that extensification by changing the habitat conditions changed the ant assemblage. This hypothesis was partly confirmed: The ant assemblage of the constantly managed coppice was individual poor, species poor (consisting mainly of generalists) and was of logarithmic structure (i.e numerically dominated by one species) due to the high relative abundance of Myrmica rubra Linnaeus 1758. The ant assemblage of the extensified coppice was characterised by increased total worker abundance and increased species richness due to the arrival of rotting wood specialists and one heliophile species. The assemblage structure, however, remained logarithmic due to the increased percentage abundance of M rubra. Reasons for this could be a high tolerance of M rubra to floods as well as underestimation of the abundance of rotting wood specialists. All investigated ant assemblages lacked top competitor species. In contrast to most other known ant assemblages, the studied assemblages were apparently shaped by environmental factors rather than interspecific interactions. Concluding, the extensification of coppices, which will in future take place in Central Europe on a large scale, increases their conservation value from the point of view of ants, at least over the medium term.