Alien competitors

[Geomyda]

1) Predator Recognition of Native (Euopean Pond) But Not Invasive Turtle Predators (red-eared sliders) by naïve anuran tadpoles - Result- sliders out compete native turtles for food
Animal Behaviour
Volume 80, Issue 3, September 2010, Pages 461-46
Nuria Polo-Cavia, a, , Adega Gonzalo1, a, Pilar López1, a and José MartÃ*n1, a
a Departamento de EcologÃ*a Evolutiva, Museo Nacional de Ciencias Naturales, CSIC, Spain

The impact of alien predators on prey populations is well known by conservation biologists, but little attention has been paid to the negative effects that the introduction of exotic predators may have on native predators through competition for food. In the Iberian Peninsula, the red-eared slider, Trachemys scripta elegans, and other exotic freshwater turtles have been introduced, competing and displacing the native endangered terrapins (the European pond turtle, Emys orbicularis, and the Spanish terrapin, Mauremys leprosa). Although the nature of competitive interactions remains unclear, direct competition for food is likely to occur. Both native and invasive freshwater turtles are common predators of amphibian tadpoles. Naïve amphibian tadpoles are known to recognize and respond to local predators with no prior experience, but tadpoles might not recognize new predatory species, since they have not shared a long evolutionary history with them. We examined the ability of fo!
ur species of Iberian anuran tadpoles to recognize and respond to chemical cues from invasive and native freshwater predatory turtles. Three of the four tadpole species tested reduced their swimming activity when cues from native turtles were present in water, but not when cues belonged to exotic turtles. This inability of tadpole prey to respond innately to chemicals from introduced predatory turtles might be one of the causes that explains the displacement of native populations of Iberian terrapins by invasive exotic turtles, and may help clarify why alien predators sometimes prosper better in new habitats than locally adapted predators.
Correspondence and present address: N. Polo-Cavia, Departamento de BiologÃ*a, Universidad Autónoma de Madrid, Ciudad Universitaria de Cantoblanco, 28049 Madrid, Spain.

[TortBabe]

That is interesting

[Geomyda]

Originally Posted by TortBabe

That is interesting

Poor Spanish Frogs and Toads do not stand a chance!
Maybe, Bindi's bedroom visitor recently was an Iberian Frog looking for a safe haven from these Alien invaders?

[TortBabe]

Quite possibly, I hope this problem does not come this way, i don't live far from a river
I would faint if a frog was in my bedroom

[harwood09]

Thats very interesting and gives an insight into why sliders seem to be so good at being an invasive species. Thats a hell of an advantage to have if your a turtle in a new habitat must be like going to a buffet for them during spawing season must be why so many manage to survive as they must be able to put on that all important weight before hibernation sooner than their native counterparts.

Wonder if the same happened in asia when RES were first introduced to the wildlife. That was a while ago I wonder whether the wildlife there has adapted to recognise them as a natural predator yet?

[Geomyda]

Mutant turtles terrorising London ponds
Evening Standard 25 May 2011
Hybrid turtles are taking hold of London's parks and ponds.

Experts studying 1,600 square kilometres of London and the home counties were shocked to find 10 species and several hybrids. They even found rare African turtles in a Camden park.

Despite culls, numbers are growing. Tom Langton of the London Natural History Society said: "We found a big increase in the sightings of terrapins, a type of turtle popular in the Eighties due to the Teenage Mutant Ninja Turtle cartoon series."

A government ban in 1997 has led to "lookalike" species being sold cheaply in pet shops. Mr Langton said he hoped all terrapins would be banned in the UK.

[Geomyda]

One show tonight: Mike Dilger did an interview with a Terrapin Trapper/ Rescue guy, called Wayne. Sadly, he misidentified one of the species apparently fished out of a municiple pond;it seems the BBC, cocked up again. The Razor back Terrapin described in the sequence, was of course a Map Turtle(Graptemys spp) and I very much doubt that the Chelodina spp were actually fished out of a UK pond. That said, the issue is clear: We have a very significant feral population of unwanted "ex pet" Terrapins, which are patently non native, in many of our waterways. What are we going to do about it?