Ant diversity sampling on the southern Cumberland Plateau: A comparison of litter sifting and pitfall trapping

Abstract

We compared the efficacy and biases of pitfall trapping and Winkler extraction of sifted leaf litter for sampling the diversity of ground-dwelling ants in native oak-hickory hardwood forest and cultivated pine stands on the Cumberland Plateau in southern Tennessee. Samples yielded 2,635 individuals from 23 species, 17 genera, and 4 subfamilies. According to estimates of expected species richness, our sampling effort inventoried at least 82% of the ant fauna likely to be captured by these methods at a given site. Litter sifting yielded more individuals, more species and more occurrences of most species than did pitfall traps, but neither method captured all species. Most myrmicine and all ponerine species showed a significant bias toward capture by litter sifting, whereas pitfall traps tended to be more effective at capturing large-bodied Camponotus ants and species that forage outside of prime daylight hours, when litter samples were collected. Large pitfalls (75 mm diameter) caught more species and more individuals than small pitfalls (25 mm diameter). The preliminary survey indicated that a change from native hardwood to cultivated pine reduced species richness and altered the assemblage of ant species present, but did not alter community diversity or abundance of ants. Larger scale surveys involving commercial pine plantations are needed for more accurate assessments of how this type of land use change affects local ant diversity and ecosystem functioning.