Diversity and resilience of seed-removing ant species in longleaf sandhill to frequent fire

Authors: Atchison, Rachel; LUCKY, ANDREA - University Of Florida

Submitted to: Diversity
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/18/2022
Publication Date: 11/22/2022
Citation: Atchison, R.A., Lucky, A. 2022. Diversity and resilience of seed-removing ant species in longleaf sandhill to frequent fire. Diversity. 14(12):1012. https://doi.org/10.3390/d14121012.
DOI: https://doi.org/10.3390/d14121012

Interpretive Summary: Longleaf pine forests are a biodiverse habitat in the US Southeast with about only 3% of the habitat existing before Europen settlement remaining. In areas undergoing restoration and conservation, frequent, periodic prescribed fire is a key management practice. Whereas many studies have explored effects of management practices such as fire and presence of coarse downed wood on plants and vertebrates, little research ghas focused on ants, which shape plant communities through seed disepersal and predation. In this study, USDA-ARS and the Univ. of FL. scientists identified seed-removing ant species in longleaf pine forest and investigated how prescribed fiore and corase downed wood affect ant community composition and ant-seed interactions. This study took place from spring 2017 to summer 2018 at a longleaf snadhill site at Ordway-Swisher Biological Station, with a prescribed burn applied to half of the plots in summer 2017. Leaf litter sampling, and baiting with plant seeds and tuna-honey mixtures were used to monitor ant species and their behavior through time in plots with or without coarse woody debris. Through leaf litter sampling, a total of 45 ant species were collected. Twenty species participated in seed removal-8 of which did not have previous documentaions of seed interaction. In comparision to the overall ant community, seed-removing ant species exhibited relative stability across time in burned areas. The amount of seeds removed declined in the late summer and fall season, but this was true regardless of coarse woody debris presence or fire application. These results suggest the pressence and activity of seed-removing ant species is robust to the most significant habitat changes mediated by longleaf pine fire management. As a result, fire management as a restoration and conservation practice in longleaf pine forest appears to be compatible with and may support native ant density. More species-specific ant studies are needed to better understand ant interactions with coarse woody debris interactions and the fate of ant-dispersed plant seeds.

Technical Abstract: Prescribed fire is used globally as a habitat restoration tool and is widely accepted as supporting biotic diversity. However, in fire-prone ecosystems, research has sometimes documented post-fire reduction in ant diversity and accompanying changes in seed removal behavior. This is concerning because ants provide important ecosystem services that can aid in restoration efforts, including seed dispersal. In this study, we examined the immediate impacts of fire in the well-studied ant community of longleaf pine forests (LLP) in the SE USA. We surveyed seed-removing ant species in a LLP sandhill ecosystem to investigate the effects of prescribed fire and coarse woody debris (CWD), a nesting and foraging resource, on ant community composition and ant–seed interactions. Seed-removing ants comprised a significant portion of detected ant species (20 of 45); eight of these species are documented removing seeds for the first time. Following an experimentally applied low-intensity summer burn, decreases in seed remover detection were observed, along with reductions in the number of seeds removed, across both burned and unburned areas; neither prescribed fire nor proximity to CWD significantly influenced these factors. Together, these results show that seed-removing ant species constitute a substantial proportion of the LLP sandhill ant community and are relatively robust to habitat changes mediated by low-intensity prescribed burning during the growing season. Considering ant community resiliency to fire, we can infer that using prescribed fire aligns with the goals of restoring and maintaining biotic diversity in this fire-prone ecosystem.