Managed Fire Frequency Significantly Influences the Litter Arthropod Community in Longleaf Pine Flatwoods

Frequent prescribed burns are essential to pine forest restoration and management. Research studies have assessed effects of prescribed fire and burn frequency on plants and vertebrates, but impacts of fire on terrestrial invertebrate communities are still poorly understood. This case study investigated effects of burning frequency on species richness and community composition of social insects (ants, Hymenoptera: Formicidae and termites, Blattodea: Isoptera) in fire-managed Southern longleaf pine flatwoods in central Florida. Community response to different fire frequencies was assessed: burned annually, every 2 yr, or every 3 yr, 30 yr unburned and 75 yr unburned. Richness was similar across all treatments, but ant community composition and species density significantly differed between frequently burned (1, 2, and 3 yr) and long-unburned (30 and 75 yr) treatments. Long-unburned treatments had higher ant abundance, but the species present were less characteristic of open canopy longleaf pine habitat than ants in frequently burned treatments. The annual burn treatment differed from 2-yr burn in species density, but to a lesser degree. Exotic species abundance was highest in frequently burned sites; only native species were detected in the 75-yr unburned plot. The red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), was detected in all regularly burned plots but not in long-unburned sites. Frequent burning at this site increased habitat suitability for ant species adapted to the sunny, open canopy, and diverse niches characteristic of longleaf pine forest; however, regular fire disturbance also increased the likelihood of exotic ant species establishment.