Assessing the needs for a sound management of the introduced populations of reptiles and amphibians in Italy Trachemys scripta elegans and Rana catesbeiana as a case study Riccardo SCALERA
Amphibians and reptiles introduced in the world Cane toad (Bufo marinus) Australia Introduced in 1935 as a biological control for cane beetles. Diet includes small lizards, frogs, mice and even younger toad. Highly poisonous to eat, at every stage of the life cycle.
Amphibians and reptiles introduced in the world Brown tree snake (Boiga irregularis) Guam Responsible for the extinction of 9 native forest birds and 3 of Guam's 12 native lizards Is threatening the endangered Guam rails
Amphibians and reptiles introduced in the world Caribbean tree frog (Eleutherodactylus coqui) Hawaii Prey upon Hawaii's unique insects and spiders. Compete with endemic birds and other native fauna that rely on insects for food
Amphibians and reptiles introduced in the world Fowler s snouted tree frog (Scinax quinquefasciata) Galapagos The first amphibian species of the evolutionary history of the archipelago
Amphibians and reptiles introduced in the world Global Invasive Species Database total=284 exotic species ~ 1% Reptiles Boiga irregularis Norops sagrei Trachemys scripta
Amphibians and reptiles introduced in the world Global Invasive Species Database total=284 exotic species ~ 1,4% amphibians Bufo marinus Eleutherodactylus coqui Rana catesbeiana Xenopus laevis
Amphibian and reptile species introduced in Italy Amphibians Rana catesbeiana Rana kurtmuelleri Reptiles Trachemys scripta elegans Testudo graeca Testudo marginata Podarcis filfolensis?
Species reported occasionally in Italy Mauremys sp. Chamaeleo chamaeleon Testudo kleinmanni Chelydra serpentina Agama spinosa Agama agama
Species translocated in Italy Reptiles Hemidactylus turcicus Tarentola mauritanica Euleptes europaea Cyrtopodion kotschyi Chalcides ocellatus Testudo hermanni Emys orbicularis Elaphe quatuorlineata Malpolon monspessulanus Coronella girondica Vipera ammodytes Amphibians Proteus anguinus Hydromantes ambrosii Hydromantes italicus Triturus alpestris
Species translocated in Italian islands Reptiles Podarcis sicula Chalcides chalcides Natrix maura Elaphe longissima Vipera aspis Amphibians Rana bergeri + Rana kl. hispanica. Coluber hippocrepis
The least wanted: 100 of the world s worst invasive alien species Red-eared slider (Trachemys scripta elegans) Bullfrog (Rana catesbeiana)
Trachemys scripta Distribution: Native Eastern USA Mississippi Valley drainage Introduced South East and Far East Asia, Australia, New Zealand, the Caribbean, Brasil, Sri Lanka, Israel, Bahrain, Mariana Islands, Guam and South Africa EU Austria, Belgium, Denmark, France, Germany, Greece, Italy, The Netherlands, Portugal, Spain, Sweden, The United Kingdom, Slovakia
Rana catesbeiana Distribution: Native North America Introduced Cuba, Puerto Rico, Hispaniola, and Jamaica in the Antilles, Europe, Java, Japan, Mexico, Thailand, Korea, Taiwan, China, Brasil, Venezuela EU Belgium; Spain; UK; France; Italy; Germany; Greece; The Netherlands
...Are bullfrogs and red-eared sliders naturalised? Spain Italy France
...Are bullfrogs and red-eared sliders naturalised? Italy Belgium Spain UK France Germany Greece The Netherlands
...Are bullfrogs and red-eared sliders naturalised?...in other countries, regular introductions of bullfrogs and sliders can apparently maintain high densities because of the high longevity of most individuals....even though reproduction does not occur!
Trachemys scripta & Rana catesbeiana Ecological impact: Predation upon indigenous species (insects and other invertebrates, fish, amphibians, reptiles, birds and small mammals)
Trachemys scripta & Rana catesbeiana Ecological impact: Competition with indigenous species for food and cover (also basking sites and nesting sites for pond turtles)
Trachemys scripta & Rana catesbeiana the unnatural history: The presence of nonnative fish can foster bullfrog invasion by eating native dragonfly nymphs that would normally prey on bullfrog larvae. In general fish do not eat bullfrog tadpoles.
Trachemys scripta & Rana catesbeiana Sanitary impact: Spread of diseases and parasites (i.e. Salmonella and Chytridiomycosis)
Trachemys scripta & Rana catesbeiana Economic impact: 270,000 euro to control bullfrogs in Germany in 5 ponds (4.4 billion euro in all German ponds) 29,000 dollars in UK for one site
Management options Prevention Eradication Control Containment
Eradication and control techniques For sliders Hand collection Traps (i.e. floating basking traps or floating baited traps) Hook and line
Eradication and control techniques For bullfrogs Drainage of ponds Hand collection Traps (i.e. nets, drift fences and pitfall) Chemicals (i.e. rotenone, caffeine sprays, change in water salinity) Electrofishing apparatus Shotguns Fishing rod and frog-gig
Odd control techniques For amphibians For reptiles Explosives Toad proof fences Toad blaster PVC Pipe as a trap Promoting food consumption Bounty system Hunting competition Tracking dogs
Eradication and control Once captured techniques Animals must be managed according to the prevailing legislation, cultural and economic constraints disposal in captivity (i.e. rescue centres) return to their country of origin euthanasia sterilisation etc. Guidelines for the Placement of Confiscated Animals (2000)
PREVENTION It is clear that preventing the problem is cheaper than solving it through ecological management or eradication. Eradication is not always feasible both for technical, legal or ethical reasons. It would be much more realistic to focus on a sound and effective prevention strategy
Williamson M., 1996 The Tens Rule Biological invasions. Chapman & Hall, London, UK Most invasions fail, only a limited number of taxa succeed. 10% of introduced species become naturalised, and approximately 10% of those naturalised become invasive.
Lockwood J.L., 1999 Using taxonomy to predict success among introduced avifauna: relative importance of transport and establishment. Conservation Biology, 13(3):560-567. Likelihood of successful establishment is not random. Human influence seems to obscure any trait based taxonomic patterns in successful establishment. The trouble in finding general patterns in invasion ecology may lie in the influence humans maintain on the probability of purposeful transport.
The role of trade International trade and tourism have demonstrated to be a major cause for intentional and nonintentional introductions of animal and plant species beyond their biogeografical boundaries. There is strong evidence that trade in potentially harmful invasive species needs to be strictly regulated.
The role of trade Early intervention to block the invasion of exotic species would be more effective, and more cheaper, than removing the invaders completely. The suspension of trade would diminish the release in the wild of captive specimen, and as a consequence would foster the rarefaction of the specie introduced but not yet naturalised from large sectors of the newly colonised areas.
...Is there any useful legislation into force? EU wildlife trade regulations The Habitats directive
EU Wildlife Trade Regulations Council Regulation (EC) No 338/97 on the protection of species of wild fauna and flora by regulating trade therein, as amended Article 9(6) the Commission may establish restrictions on the import of live specimens of species for which it has been established that their introduction into the natural environment of the Community present an ecological threat to wild species of fauna and flora indigenous to the Community
EU Wildlife Trade Regulations Community Regulation (EC) No 2551/97 suspending the introduction into the Community of specimens of certain species of wild fauna and flora Trachemis scripta elegans Rana catesbeiana
The pet trade (part I) ~ 52 million individuals Trachemys scripta elegans exported from the US between 1989 and 1997 (Telecky, 2001). ~ 8 million Trachemys scripta individuals exported annually from the USA to the European and Asian markets (Hoover, 1998) From ~ 50-150 commercial farms (Moll, 2005)
The pet trade (part II) After the suspension of trade of Trachemys scripta elegans in 1997 ~ 24 million individuals Trachemys scripta elegans exported from the US between 1998 and 2002 (Schlaepfer et al., 2005). T. scripta scripta, T. scripta ornata, and similar species, such as T. decussata and Chrysemys floridana, are found in commerce.
Seizures and prosecutions Italy OPERATION "ELEGANS" CITES Service of the Forest Corps Airports: Fiumicino and Malpensa Date: 1999-2000 (still in progress?) Specimens seized: 22.916 Economic value: 296.000 Euro Other cases: Austria, Belgium, Denmark, Spain, Germany, The Netherlands Source: 2002 EU Wildlife Trade Regulations biennial reports
Seizures and prosecutions Italy - criminals use to falsify the documents and to alter the colour of the red spot typical of the species, by keeping the animals in dark rooms without food for several days, so resembling other subspecies whose import is not regulated. Spain - 3000 living hybrid specimen of Trachemys scripta elegans were seized in 2000. They were declared as Trachemys scripta troosti. Belgium - Some specimens of Rana catesbeiana had been seized in July and August 2003. They had come from big breeding operations in Italy and were sold in Belgium. The corresponding bills only mentioned fish.
The pet trade (part III) After the suspension of trade of Trachemys scripta elegans in 1997 Chrysemys picta was identified as a potential replacement for T.s.elegans In Germany ~ 6000 individuals were imported in the first 6 months of 1999 Reproduction in the wild was observed in 2002
EU Wildlife Trade Regulations Community Regulation (EC) No 252/2005 suspending the introduction into the Community of specimens of certain species of wild fauna and flora Trachemis scripta elegans Rana catesbeiana Chrysemys picta Oxyura jamaicensis
The Habitats directive Council Directive 92/43/EEC on the conservation of natural habitats and wild fauna and flora Article 22 establishes that the deliberate introduction into the wild of any species which is not native to their territory is regulated so as not to prejudice natural habitats within their natural range or the wild native fauna and flora and, if they consider it necessary, prohibit such introduction.
The LIFE program For the implementation of the Habitats Directive and the development of the Natura 2000 network This instrument consists of three branches: LIFE Nature, LIFE Environment and LIFE Third Countries Started its third phase (2000-2004) under Regulation (EC) No. 1655/2000, with a budget of 640 million Euros
The LIFE program For the implementation of the Habitats Directive and the development of the Natura 2000 network Between 1992 and 2002 the Commission spent ~ 30 million Euro on more than 100 projects including control or eradication actions
Recommendations Public perception will ultimately drive policy makers choices to deal with alien species. Thus, given the pivotal role of prevention as a major strategy to face the problem: Authorities and NGOs are strongly encouraged to educate the public on potential danger of introductions of pets. Scientists and conservationists should stimulate the revision of the legal framework at a regional or global level to prevent introductions of alien species. Authorities and NGOs should support a stricter enforcement of the existing legal measures to prevent the movement of alien species (i.e. updating the list of species whose trade is suspended, developing a sound scientific protocol to identify priorities).
Recommendations Wildlife trade regulations are certainly a good starting point for this purpose (although the mechanisms are neither adequate nor intended to control the movement of an unknown number of species). Costs for border control would be lower than those foreseen for the implementation of a new law specifically dedicated to alien species. Presence of an advisory group or single experts should be foreseen in every public administration to support policy makers on conservation issues (and to verify whether current research programmes meet conservation needs). EU legislation should be better harmonised. Exotic species should have a legal status compatible to management programmes.