Ant (Hymenoptera, Formicidae) diversity along a pollution gradient near the Middle Ural Copper Smelter, Russia

Ants are considered to be suitable indicators of ecological change and are widely used in land management and environmental monitoring. However, responses of ant communities to industrial pollution are less known so far. We studied pollution-related variations of ant diversity and abundance near the Middle Ural Copper Smelter (Russia) in 2009 and 2013, with pitfall traps set up at 10 sites in Picea obovata and Abies sibirica forest. This study provided evidences for humped pollution-induced dynamics of ant diversity and abundance. Species richness and diversity peaked in the habitat intermediate between slightly damaged and fully destroyed forest ecosystems. The total abundance of ants peaked in the middle of the pollution gradient and was determined mainly by the dominant species Formica aquilonia. The abundance of other species increased towards the smelter, but was less important for total abundance than that of red wood ants. Community dominants changed with increase of exposure; F. aquilonia, a typical species of mature forests, was replaced by species of open habitats, Lasius niger and Myrmica ruginodis. Habitat variables and competition between species seem to affect local ant communities more strongly than pollution exposure. Stand basal area and cover of the field layer were the main determinants of ant diversity and abundance of individual species.