Impacts of fire ant invasion on seed dispersal and ant community composition in the longleaf pine ecosystem

Abstract

The red imported fire ant (Solenopsis invicta) has extensively invaded the southeastern United States where it may alter biotic communities. We examined the influence of fire ants on native ant community composition and patterns of seed dispersal of elaiosome-bearing plants using pitfall trapping and observation of ant-seed interactions at experimental seed caches. We found that, while species richness varies independently of fire ant density, native ant abundance is negatively correlated with fire ant density. This inverse relationship may be due, in part, to the ability of native ants to limit fire ant invasion or the preference of native and fire ants for differing abiotic conditions. Fire ants were similar to native ants in quality of seed dispersal as measured by distance of dispersal and destination. Additionally, increasing densities of fire ants resulted in increases in overall rates of seed dispersal without a subsequent decline in dispersal by native ants.