Impacts of red imported fire ants (Solenopsis invicta) on nestling and hatchling gopher tortoises (gopherus polyphemus) in southwest Georgia, USA

Published source details Dziadzio M.C., Chandler R.B., Smith L.L. & Castleberry S.B. (2016) Impacts of red imported fire ants (Solenopsis invicta) on nestling and hatchling gopher tortoises (gopherus polyphemus) in southwest Georgia, USA. Herpetological Conservation and Biology, 11, 527-538.
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This study is summarised as evidence for the following.

	Action	Category
	Remove or control predators using lethal controls: Tortoises, terrapins, side-necked & softshell turtles Action Link
	Remove or control predators using fencing and/or aerial nets Action Link

Remove or control predators using lethal controls: Tortoises, terrapins, side-necked & softshell turtles

A replicated, randomized, controlled study in 2014–2015 in mixed forest and agricultural land in Georgia, USA (Dziadzio et al. 2016) found that when fire ants Solenopsis invicta were controlled with insecticide, gopher tortoise Gopherus polyphemus nests were not predated and hatchling survival rates increased. None of 16 gopher tortoise nests were predated by fire ants in insecticide-treated enclosures, compared to eight of 16 nests in untreated enclosures. Hatchling survival was higher in insecticide-treated enclosures (16 of 16 individuals survived at least 150 days) compared to untreated enclosures (5 of 16 individuals survived; five were killed by fire ants and six by raccoons Procyon lotor). Fire ant abundance were reduced in insecticide-treated enclosures (0.3–10.0 fire ants) compared to unmanaged enclosures (122–537 fire ants). In May–June 2014, wild-laid gopher tortoise nests were relocated to eight fenced 0.2 ha enclosures (four nests/enclosure, two eggs/nest, 64 total eggs). All nests were covered with cloth cages (30 x 30 x 12 cm). Four of eight enclosures were treated with Amdro® insecticide (1.7 kg/ha) to reduce fire ant numbers. Fire ants were monitored using baited traps. Nests were monitored weekly until two weeks before expected emergence, daily thereafter and excavated after 120 days. Hatchlings were radio tracked (16 individuals each from insecticide-treated and untreated enclosures) from August 2014 to March 2015.

(Summarised by: Katie Sainsbury)
Remove or control predators using fencing and/or aerial nets

A replicated, randomized, controlled study in 2014–2015 in mixed forest and agricultural land in Georgia, USA (Dziadzio et al. 2016) found that using fencing and overhead netting to control vertebrate predators (as well as nest cage covers) did not reduce predation of gopher tortoise hatchlings Gopherus polyphemus. Gopher tortoise hatchling predation by vertebrate predators in enclosures with overhead netting was the same (3 individuals) as in enclosures with no netting. Enclosures with overhead netting had fewer signs of vertebrate predators (mammals, birds and snakes) compared to those without (signs included raccoon Procyon lotor digging and tracks, no data provided). In May–June 2014, wild-laid gopher tortoise nests were relocated to eight fenced 0.2 ha enclosures (four nests/enclosure, two eggs/nest, 64 total eggs). All nests were covered with cloth cages (30 x 30 x 12 cm). Four of eight enclosures were covered with game farm netting and UV twine to exclude aerial and terrestrial vertebrate predators (mammals, birds and snakes). Four enclosures (two with overhead netting; two without netting) were also treated with insecticide to reduce fire ant numbers. Nests were monitored weekly until two weeks before expected emergence, daily thereafter and excavated after 120 days. Hatchlings were radio tracked (16 individuals each from insecticide-treated and untreated enclosures) from August 2014 to March 2015.

(Summarised by: Katie Sainsbury)