Besides its distinctive red flashes the red-eared slider (like all turtles exotic to Australia) can also be identified by the way it retracts its head straight back into the shell; in comparison, all native Australian turtles wrap their heads around to the side of their shell (NRM&W).
In Europe, T. scripta elegans are generally released in freshwater areas which are frequented by humans such as public ponds which are considered of low biological value (e.g. Kordges 1990, Thiesmeier & Kordges 1990 1991, in Bringsøe 2006). Natural habitats close to urban areas are also used for releases (Bringsøe 2006). Natural reproduction of the red-eared slider in Europe under Mediterranean climate conditions has been reported (Luiselli et al. 1997, Martinez-Silvestre et al. 1997, Cadi et al. 2003, in Cadi & Joly 2003). The occurrence of the red-eared slider in a tropical urban polluted river in Brazil supports evidence of its capacity to use anthropogenic environments. Polluted rivers can offer a high amount of organic residues and food items, which can represent an advantage for such a generalist freshwater turtle species (Moll 1980, Lindeman 1996, Souza & Abe 2000, in Ferronato et al. 2009).\n
In its introduced range in Europe egg deposition has been observed in Spain (de Roa and Roig, 1997; Martinez-Silvestre, 1997; Bertolero and Canicio, 2000; Capalleras and Carretero, 2000, in Cadi et al. 2004), and near Paris, France (Moran Pers. Comm., in Cadi et al. 2004). However, sex determination of the Trachemys embryos is temperature-dependent, with cooler incubation temperatures producing only males, and warmer incubation temperatures only females (Ewert et al. 199, in Cadi et al. 2004). Therefore, incubation temperature could be a limiting factor for the invasion of this species in parts of Europe, if hatchlings of only one sex are produced in the wild (Cadi et al. 2004). A strong bias towards female red-eared sliders has been detected in capture sampling in France. This may reflect a potential strong female bias of imported juveniles; the incubation at high temperature leads to rapid hatching, but produces females in this species with temperature dependent sex determination (Godfrey et al. 2003, in Prévot-Julliard et al. 2007).
In northern Taiwan all feral T. scripta elegans sampled were found to have ingested animal materials (mostly snails, fish, adult and larval flies and unidentifiable terrestrial insects) and 76.5% were found to have ingested plant materials (Chen & Lue 1998, in Outerbridge 2008). Conversely Outerbridge (2008) found that only 77.8% of feral red-eared sliders examined in Bermuda had ingested animal materials whereas 86.1% had ingested plant materials. Most of the vegetative matter consisted of leaves, stalks, roots, seeds and flowers; however, filamentous and blue-green algae were also occasionally ingested. Nearly half of the animal material ingested comprised aquatic and terrestrial insects. Small fish, freshwater snails and bird remains occurred less frequently in the samples (Outerbridge 2008). \n
Prévot-Julliard et al. (2007) found fish remains in the stomachs of turtles. The size of fish scales found, some up to 12 mm in diameter, would have belonged to 20 cm fish (J.Y. Sire, Pers. Comm., in Prévot-Julliard et al. 2007). As it is unlikely that a slider turtle would be rapid enough to catch a 20 cm fish, perhaps the turtle acted as a necrophagous species, as other species of freshwater turtles do (Spencer et al. 1998, in Prévot-Julliard et al. 2007).\n
Prévot-Julliard et al. (2007) found four individuals which had ingested terrestrial ants, and one stomach was full of them. Although terrestrial activity is known for this species (Bennett et al. 1970, Gibbons 1970, in Prévot-Julliard et al. 2007), only few report are available for terrestrial foraging (Cagle 1944, Chen & Lue 1998, in Prévot-Julliard et al. 2007). The terrestrial activity of slider turtles is a key component for the colonisation of new habitat (Parker 1990, in Prévot-Julliard et al. 2007) making further investigation into this aspect of the turtle’s behavior warrented.
Principal source:
Compiler: IUCN SSC Invasive Species Specialist Group
Updates with support from the Overseas Territories Environmental Programme (OTEP) project XOT603, a joint project with the Cayman Islands Government - Department of Environment
Review: Paul Pendelbury, REPTRANS UK
Publication date: 2010-05-26
Recommended citation: Global Invasive Species Database (2024) Species profile: Trachemys scripta elegans. Downloaded from http://www.iucngisd.org/gisd/species.php?sc=71 on 08-12-2024.
Trachemys scripta elegans has been the most popular turtle in the pet trade with more than 52 million individuals exported from the United States between 1989 and 1997 (Telecky 2001, in Bunnell 2005). Slider turtles became very popular because of their small size, their simple husbandry requirements and their reasonably low price (Teillac-Deschamps et al. 2008). Unsuspecting turtle owners were rarely prepared to maintain large adults (up to 30 cm carapace length) for a significant length of time (up to 50 years) in captivity (Teillac-Deschamps et al. 2008). Larger adult turtles were released by their owners to ponds in many places and because of this, red-eared sliders now occur in freshwater ecosystems in many developed countries with high densities in urban wetlands (de Roa & Roig 1997, Luiselli et al. 1997, Arvy & Servan 1998, Chen & Lue 1998, Lever 2003, Martinez-Silvestre et al. 2003, in Teillac-Deschamps et al. 2008).\n
Competition: The competitive advantages of the slider may include lower age at maturity, higher fecundity, and larger adult body size (Arvy & Servan 1998, in Cadi & Joly 2003). Turtles may compete for food, egg-laying sites, or basking places (Bury & Wolfheim 1973, Bury et al. 1979, Rovero et al. 1999, Lindeman 1999, in Cadi & Joly 2003). In a study by Cadi and Joly (2003), Emys were shown to shift their basking activity toward places considered to be of lower quality, while the dominant Trachemys occupied the better basking sites. Other studies have also shown red-eared sliders to compete with indigenous species for food and basking sites (Frank & McCoy 1995, Williams 1999, Salzberg 2000, in Somma & Fuller 2009). The red-eared slider has also been considered occasionally aggressive towards other individuals (Cadi & Joly 2003).\n
Threat to Endangered Species: Competitive interactions between T. scripta elegans and the European pond turtle (Emys orbicularis) are of particular interest, as the latter is registered as an endangered species (Appendix II of the Bern Convention, Corbett 1989, Luiselli et al. 1997, Martinez-Silvestre et al. 1997, in Cadi & Joly 2003, see Competition).\n
In Washington (USA) they are a potential threat to the Pacific pond turtle (Clemmys marmorata) a declining species endemic to the Pacific states (Brown et al. 1995, Williams 1999, in Somma & Fuller 2009). \n
Disease Transmission: Continuous releasing of exotic pet turtles in natural ecosystems increases the risk of parasite transmission to native species, and highlights the impending need for regulation of pet turtle trade in Europe (Hidalgo-Vila et al. 2008); the red-eared slider is known to carry nematodes (Hidalgo-Vila et al. 2008).\n
Predation: Turtles introduced near Paris were revealed to have consumed aquatic plants and animals (mostly arthropods and molluscs, Prévot-Julliard et al. 2007, in Teillac-Deschamps et al. 2008).\n
Human Health: Reptiles, including turtles, are well-recognised reservoirs for Salmonella, and are a source of human salmonellosis (Nagano et al. 2006). \n
Ecosystem Change: The impacts of T. scripta on natural habitats and ecosystems are unknown; should the red-eared slider be released in natural habitats with high ecological value, it would be relevant to monitor any consequences on native fauna and flora, typically invertebrates, amphibians, native turtles and nesting birds (Bringsøe 2006).
Preventative measures: With effect from 22 December 1997 the EU banned the import of the subspecies T. scripta elegans via the Protection of Species of Wild Fauna and Flora by Regulating Trade (Bringsøe 1998, 2001b, Bringsøe 2006). While it is no longer allowed to import the red-eared slider within the EU it is still legal to keep and distribute them within many EU countries.
After this legislation was passed the red-eared slider was semi-replaced in the market by other North American turtles which fetch higher prices and are imported in lower quantities (Adrados et al. 2002, in Bringsøe 2006). This may change if American turtle farmers manage to improve breeding success of these species in turtle farms. Unfortunately some of the species replacing the red-eared slider in the market are substantially better adapted to cold climates (such as Nova Scotia and Siberia, respectively) and probably represent a higher ecological risk; they are cryptic species and are significantly more carnivorous than the red-eared slider (P.P. van Dijk Pers. Comm. 2006).
Risk Assessment models for assessing the risk that exotic vertebrates could establish in Australia have been further explored by the Western Australia Department of Agriculture & Food (DAFWA) to confirm that they reasonably predict public safety, establishment and pest risks across a full range of exotic species and risk levels.
The Risk assessment for the Pond Slider (Trachemys scripta), has been assigned a VPC Threat Category of EXTREME.
Mammals and birds were assessed for the pest risk they pose if introduced to Australia, by calculating Vertebrate Pests Committee (VPC) Threat Categories. These categories incorporate risk of establishing populations in the wild, risk of causing public harm, and risk of becoming a pest (eg causing agricultural damage, competing with native fauna, etc). The 7-factor Australian Bird and Mammal Model was used for these assessments.
\r\nPhysical: Sliders can be captured by hand or through various trapping devices. Please visit Fyke Net for Turtles for information about turtle nets. Floating boards used by sliders as basking sites seem very effective when equipped with baited cages on top (Scalera 2006). Sniffer dogs can be used to detect and remove both turtles and their eggs; eggs can also be found and removed by following females at nesting areas (Scalera 2006).
In parts of Asia animals are released into the wild as a part of traditional Buddhist mercy ceremony to increase good karma, honour Buddha and repent for ones sins. The Ministry of the Environment (Republic of Korea ) advised that people should consider taking care of injured birds and animals and then set them free for a more environmentally-friendly symbolic act.
Knowledge and Research: The ecological effects of introductions of T. scripta elegans have been poorly documented (Platt & Fontenot 1992, in Ramsay et al. 2007). Competition of T. scripta elegans with the 'Lower Risk/Near Threatened (NT)' indigenous European pond turtle (see Emys orbicularis in the IUCN Red List of Threatened Species) has been studied in France (see Cadi & Joly 2003). A French management project for the red-eared slider was initiated by the laboratory “Ecologie, Systématique and Evolution” (CNRS-University Paris-Sud) (Cadi et al. 2008).
Location | Status | Invasiveness | Occurrence | Source |
Trachemys scripta elegans has been the most popular turtle in the pet trade with more than 52 million individuals exported from the United States between 1989 and 1997 (Telecky 2001, in Bunnell 2005). Slider turtles became very popular because of their small size, their simple husbandry requirements and their reasonably low price (Teillac-Deschamps et al. 2008). Unsuspecting turtle owners were rarely prepared to maintain large adults (up to 30 cm carapace length) for a significant length of time (up to 50 years) in captivity (Teillac-Deschamps et al. 2008). Larger adult turtles were released by their owners to ponds in many places and because of this, red-eared sliders now occur in freshwater ecosystems in many developed countries with high densities in urban wetlands (de Roa & Roig 1997, Luiselli et al. 1997, Arvy & Servan 1998, Chen & Lue 1998, Lever 2003, Martinez-Silvestre et al. 2003, in Teillac-Deschamps et al. 2008).\n
Competition: The competitive advantages of the slider may include lower age at maturity, higher fecundity, and larger adult body size (Arvy & Servan 1998, in Cadi & Joly 2003). Turtles may compete for food, egg-laying sites, or basking places (Bury & Wolfheim 1973, Bury et al. 1979, Rovero et al. 1999, Lindeman 1999, in Cadi & Joly 2003). In a study by Cadi and Joly (2003), Emys were shown to shift their basking activity toward places considered to be of lower quality, while the dominant Trachemys occupied the better basking sites. Other studies have also shown red-eared sliders to compete with indigenous species for food and basking sites (Frank & McCoy 1995, Williams 1999, Salzberg 2000, in Somma & Fuller 2009). The red-eared slider has also been considered occasionally aggressive towards other individuals (Cadi & Joly 2003).\n
Threat to Endangered Species: Competitive interactions between T. scripta elegans and the European pond turtle (Emys orbicularis) are of particular interest, as the latter is registered as an endangered species (Appendix II of the Bern Convention, Corbett 1989, Luiselli et al. 1997, Martinez-Silvestre et al. 1997, in Cadi & Joly 2003, see Competition).\n
In Washington (USA) they are a potential threat to the Pacific pond turtle (Clemmys marmorata) a declining species endemic to the Pacific states (Brown et al. 1995, Williams 1999, in Somma & Fuller 2009). \n
Disease Transmission: Continuous releasing of exotic pet turtles in natural ecosystems increases the risk of parasite transmission to native species, and highlights the impending need for regulation of pet turtle trade in Europe (Hidalgo-Vila et al. 2008); the red-eared slider is known to carry nematodes (Hidalgo-Vila et al. 2008).\n
Predation: Turtles introduced near Paris were revealed to have consumed aquatic plants and animals (mostly arthropods and molluscs, Prévot-Julliard et al. 2007, in Teillac-Deschamps et al. 2008).\n
Human Health: Reptiles, including turtles, are well-recognised reservoirs for Salmonella, and are a source of human salmonellosis (Nagano et al. 2006). \n
Ecosystem Change: The impacts of T. scripta on natural habitats and ecosystems are unknown; should the red-eared slider be released in natural habitats with high ecological value, it would be relevant to monitor any consequences on native fauna and flora, typically invertebrates, amphibians, native turtles and nesting birds (Bringsøe 2006).
Preventative measures: With effect from 22 December 1997 the EU banned the import of the subspecies T. scripta elegans via the Protection of Species of Wild Fauna and Flora by Regulating Trade (Bringsøe 1998, 2001b, Bringsøe 2006). While it is no longer allowed to import the red-eared slider within the EU it is still legal to keep and distribute them within many EU countries.
After this legislation was passed the red-eared slider was semi-replaced in the market by other North American turtles which fetch higher prices and are imported in lower quantities (Adrados et al. 2002, in Bringsøe 2006). This may change if American turtle farmers manage to improve breeding success of these species in turtle farms. Unfortunately some of the species replacing the red-eared slider in the market are substantially better adapted to cold climates (such as Nova Scotia and Siberia, respectively) and probably represent a higher ecological risk; they are cryptic species and are significantly more carnivorous than the red-eared slider (P.P. van Dijk Pers. Comm. 2006).
Risk Assessment models for assessing the risk that exotic vertebrates could establish in Australia have been further explored by the Western Australia Department of Agriculture & Food (DAFWA) to confirm that they reasonably predict public safety, establishment and pest risks across a full range of exotic species and risk levels.
The Risk assessment for the Pond Slider (Trachemys scripta), has been assigned a VPC Threat Category of EXTREME.
Mammals and birds were assessed for the pest risk they pose if introduced to Australia, by calculating Vertebrate Pests Committee (VPC) Threat Categories. These categories incorporate risk of establishing populations in the wild, risk of causing public harm, and risk of becoming a pest (eg causing agricultural damage, competing with native fauna, etc). The 7-factor Australian Bird and Mammal Model was used for these assessments.
\r\nPhysical: Sliders can be captured by hand or through various trapping devices. Please visit Fyke Net for Turtles for information about turtle nets. Floating boards used by sliders as basking sites seem very effective when equipped with baited cages on top (Scalera 2006). Sniffer dogs can be used to detect and remove both turtles and their eggs; eggs can also be found and removed by following females at nesting areas (Scalera 2006).
In parts of Asia animals are released into the wild as a part of traditional Buddhist mercy ceremony to increase good karma, honour Buddha and repent for ones sins. The Ministry of the Environment (Republic of Korea ) advised that people should consider taking care of injured birds and animals and then set them free for a more environmentally-friendly symbolic act.
Knowledge and Research: The ecological effects of introductions of T. scripta elegans have been poorly documented (Platt & Fontenot 1992, in Ramsay et al. 2007). Competition of T. scripta elegans with the 'Lower Risk/Near Threatened (NT)' indigenous European pond turtle (see Emys orbicularis in the IUCN Red List of Threatened Species) has been studied in France (see Cadi & Joly 2003). A French management project for the red-eared slider was initiated by the laboratory “Ecologie, Systématique and Evolution” (CNRS-University Paris-Sud) (Cadi et al. 2008).