Colonisation of a burned forest by ants in the southern Finnish boreal forest.

Abstract

The colonisation of a burned clear-cut by ants in southern Finland was monitored using pitfall traps, artificial nest sites, and direct nest sampling from the ground and stumps. Clearcutting and fire seemed to have destroyed wood-ant colonies ( group), and also other mature-forest species suffered from fire. Nylander was able to survive only in less severely burned moist sites, whereas it benefitted from the enhanced light conditions in a non-burned clear-cut. The fire resulted in an essentially ant-free terrain into which pioneering species immigrated. The mortality of nest-founding queens appeared to be high. The results supported the hypothesis that the pioneering species tend to be those that are capable of independent colony founding, followed by species founding nests through temporary nest parasitism. The succession of the burned clear-cut differed from that of the non-burned one, suggesting that habitat selection in immigration and priority effects, i.e. competition, introduce deterministic components in the successional pathways of boreal ant communities. Formica rufaMyrmica ruginodis