1st Place: D3152: What abiotic or biotic factors are affecting ants in longleaf pine savannas in North Carolina?

Longleaf pine savannas are unique and diverse ecosystems, therefore colonization by invasive species such as red imported fire ants (Solenopsis Invicta) and Asian needle ants (Brachyponera Chinensis) may pose threats to native species. Fire ant nest density surveys were conducted along belt transects in 2014, 2017, and 2022 in three longleaf pine savannas. Pitfall traps were used to measure the abundance and richness of ants along the transects in 2017 and 2022. In 2017, S. Invicta comprised most of the invasive ant abundance. We resurveyed the same sites in 2022 and found 65% higher ant abundance (799 ants) compared to the abundance (484 ants) for 2017, but an overall decrease in species richness from 22 species to 15. The abundance change was due to large increases in B. Chinensis across all sites, jumping from 19% of the abundance in 2017 to over half of the individuals collected in 2022. Conversely, S. Invicta abundance and nest density decreased at most sites, suggesting the two invasive species are competing with each other, while also negatively affecting native ant richness. These savannas are some of the most diverse in terms of fauna and flora in North Carolina, so it is paramount to understand the impact of these invasive ants in order to mitigate any environmental effects of the species.