Red Imported Fire Ants Reduce Invertebrate Abundance, Richness, and Diversity in Gopher Tortoise Burrows

Deborah M Epperson,Craig R Allen,Katharine F E Hogan

doi:10.3390/d13010007

Deborah M Epperson, Craig R Allen + Show 1 more

Open Access

https://doi.org/10.3390/d13010007

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Abstract

Gopher Tortoise (Gopherus polyphemus) burrows support diverse commensal invertebrate communities that may be of special conservation interest. We investigated the impact of red imported fire ants (Solenopsis invicta) on the invertebrate burrow community at 10 study sites in southern Mississippi, sampling burrows (1998–2000) before and after bait treatments to reduce fire ant populations. We sampled invertebrates using an ant bait attractant for ants and burrow vacuums for the broader invertebrate community and calculated fire ant abundance, invertebrate abundance, species richness, and species diversity. Fire ant abundance in gopher tortoise burrows was reduced by >98% in treated sites. There was a positive treatment effect on invertebrate abundance, diversity, and species richness from burrow vacuum sampling which was not observed in ant sampling from burrow baits. Management of fire ants around burrows may benefit both threatened gopher tortoises by reducing potential fire ant predation on hatchlings, as well as the diverse burrow invertebrate community. Fire-ant management may also benefit other species utilizing tortoise burrows, such as the endangered Dusky Gopher Frog and Schaus swallowtail butterfly. This has implications for more effective biodiversity conservation via targeted control of the invasive fire ant at gopher tortoise burrows.

Highlights

Invertebrates are an integral component of most food webs either directly as predators, prey, or indirectly through nutrient cycling [1]
That account for a small percentage of the earth’s surface [5,6,7]. These hotspots are created by the presence of keystone or ecosystem engineer species, such as the gopher tortoise (Gopherus polyphemus) of the southeastern United States [8]
The repeated treatments with LOGIC® significantly reduced fire ant abundance in our study sites [22] and this was confirmed by the burrow baiting and burrow vacuum samples which had a 98.8% and 99.9% reduction in fire ant abundance, respectively

Summary

Introduction

Invertebrates are an integral component of most food webs either directly as predators, prey, or indirectly through nutrient cycling [1]. That account for a small percentage of the earth’s surface [5,6,7] Sometimes, these hotspots are created by the presence of keystone or ecosystem engineer species, such as the gopher tortoise (Gopherus polyphemus) of the southeastern United States [8]. No other North American reptile digs such a large, extensive, and relatively stable burrow [12], which makes the associated community of particular interest. In addition to their longevity in upland habitats, these burrows provide a stable thermal refugia for tortoises and other species [13]

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