Effects of prescribed fire on an ant community in Florida pine savanna

Abstract.  1. The effects of prescribed fire on ant community structure were examined in a regenerating longleaf pine savanna in Florida, U.S.A. The presence of ants on 20, 10 × 10 m plots was determined by baiting every 1–3 months from 18 months before a fire until 6 months afterwards.
2. Expected species richness (based on rarefaction) and species density 6 months post-fire were significantly lower than for the same month (September) 6 months before the fire.
3. Cluster analysis revealed that the effects of fire were far less important predictors of ant community structure than seasonality and unexplained inter-annual variation. Thus, overall, the impacts of fire were relatively minor and short term at the community level.
4. Different functional groups of ants (as defined by Andersen, 1997) responded to fire in strikingly different ways. Generalised Myrmicinae (e.g. Pheidole spp., Monomorium viride ) were affected more severely by fire than were the other functional groups. In contrast, the dominant Dolichoderinae ( Forelius pruinosus ) exhibited a large increase after the fire and seemed to be responsible for the decline in abundance of several species.
5. A strong negative correlation between F. pruinosus and other groups of ants immediately after the fire suggested more intense competition among ants at that time. Six months post-fire, the abundance of F. pruinosus decreased markedly and the abundance of other species rebounded.
6. The rapid post-fire recovery of the ant community probably reflects adaptations of ants to a chronic fire regime.