Wood Ants in the Białowieża Forest and Factors Affecting their Distribution

Abstract

Wood ants are common in coniferous, mixed and deciduous forests of the Palaearctic ecozone. We conducted a survey of wood-ant mounds in an area of 1400 ha in the Bialowieza Forest (NE Poland) and related physical mound characteristics to the surrounding forest properties. The overall density of inhabited wood-ant mounds was 0.13 per ha. Formica polyctena and F. rufa were the most abundant species, and the highest densities of their mounds were found in fresh mixed deciduous and fresh mixed coniferous forests. The physical mound properties, such as direction of the longest mound slope and the distance to the closest tree did not differ significantly between these two ant species. Amount of light significantly affected mound size and the distance to the closest tree distance: mound diameter, height and volume increased with increasing shade; and the distance to the closest tree with increasing amount of light. The results of our study suggest that coniferous forests with an admixture of deciduous trees are best for maintaining wood-ant populations.