INTRODUCTION

1. Survey of Invasive Fire Ants in Pristine Wetlands in South-Central North Carolina Gareth M. Hoffmann and Lisa A. Kelly University of North Carolina at Pembroke 1 University Drive Pembroke, NC 28372 INTRODUCTION DISCUSSION FIG. 1B FIG. 1A All study sites were infested with invasive fire ants. Two sites were considered to be far more infested than the other sample sites. The sites most heavily infested were Pretty Pond in Saint Pauls, NC, and Seventeen Frog Pond in Hoffman, NC. Invasive fire ants were found among varying types of mounds. Depending on the habitat of each bay seemed to foreshadow the prominence of certain mound formations. Seventeen Frog Pond was extremely open with no trees, dense grassy vegetation, and a wetland pond emanating at the center. A majority of the mounds found were at the base of the prominent clump grasses. Pretty Pond was considerably open with a thin spread of equally distributed trees throughout the bay. Grass and forb vegetation was dense with shrubs, stumps, and woody debris scattered throughout the bay. Mounds were found semi-evenly across the mound type classifications. Both of these areas had a balance of light, shade, openness, and food availability to harness invasive fire ant infestations to great magnitudes. There is no doubt this adds to the ability of the Invasive Fire Ant to spread among the bays. Greater population densities (infestation) appear to be related to the absence or near absence of a tree or shrub canopy. Greater densities may also be related to reduced incidence of flooding.  Pretty Pond and Seventeen Frog Pond may be less prone to flooding than are some of the other sites. Nearly all fire ant mounds in all sites were located against objects that gave them elevation and likely some protection against flooding events. The sites surveyed are habitat islands (Figure 5a), surrounded by fields and highways. Plow lines, which were established to restrict fire management to the sites, could be sources of introduction of fire ants. The Red Imported Fire Ant (SolenopsisinvictaBuren) (FIG 1A) is one of the worst pest species globally. This invasive fire ant, native to central South America, was likely introduced to the United States in the 1930’s by way of cargo ships visiting the port of Mobile, Alabama. The species is currently found throughout the southern U.S. The fire ant is a ‘weedy’ species found largely in areas disturbed by human activities (lawns, roadsides, and other ‘waste’ places). Few studies have reported the presence of the fire ant in natural areas lacking anthropogenic soil disturbances. However fire ants have been found in pristine ecosystems having ‘wet’ soils and open canopy (King and Tschinkel2013). We surveyed six relatively pristine wetland ecosystems in south-central North Carolina for the presence of fire ants. Population sizes were estimated, and the relative position of each fire ant colony was mapped. Fire ants were collected for later isotope and genotype analyses. Figure 1B, above, shows the locations of study sites surveyed for invasive fire ants from May 20, 2014 – May 23, 2014 & July 1, 2014 – July 15, 2014. Fig. 2A Fig. 2B Fig. 2C Fig. 2D Fig. 2H Fig. 2E Fig. 2F Fig. 2G METHODS -Left shows a free standing invasive fire ant mound. -Right shows how the ants were collected by way of straw and plastic tube. Fire ants were collected from sites located in the south-central part of North Carolina (FIG. 1B). All sites were Carolina Bay’s except one site, which was a long-leaf pine savannah. Study Sites included: Seventeen Frog Pond (FIG. 2A & 2B); Hamby’s Bay (FIG. 2C & 2D); Green Swamp – ‘Long-leaf pine savanna’(FIG. 2E & 2F); Pretty Pond (FIG. 2G & 2H); Oak Savanna (FIG. 2I). Sites were sampled during summer 2014 using two 20-meter wide belt transects, spaced at least 50 meters apart, running the width of the sites. The length of transects and the distance between transects varied between sites depending on overall size of the site. GPS co-ordinates were recorded for every colony found within each transect. The location of each colony mound was recorded relative to objects (FIG. 3) (e.g. logs, trees, etc.), and as many as 50 living workers were collected from each colony. Worker ants were then immediately starved for 12-24 hours before being frozen for future isotope and genotype studies. GPS co-ordinates were used to map the colonies per site (FIG 4a - 5b) in order to visualize the distance of the colonies from the edge of the site. DeLormeTopo USA 4.0 software was used for mapping. Area of transects, area of sites, and total number of colonies were used to generate crude population estimates (FIG. 6) of colonies per site. Fig. 2I RESULTS Figure 3, left, shows the location of every colony collected was documented and lumped into several distinct categories. Figure 6, below, shows the estimated density of fire ant colonies per site. They help show a realistic comparison of infestation in relation to each site. REFERENCES King, J. R., and W. R. Tschinkel. 2013. Experimental evidence for weak effects of fire ants in a naturally invaded pine-savanna ecosystem in north Florida. Ecol. Entomol. 38: 68-75. Nifong, T. D. 1998. An ecosystem analysis of Carolina bays in the coastal plain of the Carolinas. Ph.D. dissertation, University of North Carolina at Chapel Hill, Chapel Hill, NC. Tschinkel, W. R. 2006. The fire ants. The Belknap Press of Harvard University Press, Cambridge, MA. FIG 4(a) FIG. 3 ACKNOWLEDGEMENTS Ryan Elting, Jeffrey Marcus, and Neville Handel of The Nature Conservancy; Brady Beck and Nathan Shepard of the North Carolina Wildlife and Resource Commission; Research Initiative for Scientific Enhancement at University of North Carolina at Pembroke; UNCP Biology Department for use of laboratories and equipment. FIG 5(b) FIG 5(a) FIG. 6 Figure 4a and 5b, above, show gps locations of mounds surveyed in Hamby’s Bay and Oak Savanna respectively. Figure 5a (Example) is an aerial photograph showing why these sites are ‘habitat islands’.