14 May 2010

Terrapins on the loose!

Jeremy Douglas-Jones photographed these two terrapins (presumably Red-eared Terrapins Chrysemis scripta) at Broad Pool, which he saw there on the 12th and 13th. Jeremy expressed concerns about these reptiles possibly breeding and taking their toll on the local wildlife. If anyone has first-hand experience of adverse effects from these animals I'd be interested to hear. I saw the regular five in the top collection pond at WWT last Sunday also enjoying some sun; to my knowledge these animals have never bothered the collection ducks there and seem to coexist quite happily. As regards breeding, I suspect our climate is not warm enough for this, but please correct me if I'm wrong.
Just checked the database and I noticed that Mark Newton saw two Red-eared Terrapins at Broad Pool on 29th May 2006, which I suspect were the same individuals. Other places where these animals have been seen in recent years are Singleton Park, Gnoll Lake and Country Park, Fendrod Lake and Graigfelen, Clydach. I'd be interested to know of anymore sightings elsewhere in our area.


Nigel Ajax Lewis said...

The Wildlife Trust nature reserve of Broad Pool has a long history of unauthorised and now illegal introductions of all manner of native and non native aquatic species. This is presumably due to its easy accessibility and either a misguided concern for the life in a surplus aquarium or pond or just to beautify this Gower icon. So Fringed Water-lily (Nymphoides peltata) was introduced in the early 1950s and creates a spectacular yellow carpet in summer and horticultural hybrid White Water-lilies (Nymphaea alba varieties) have come and gone, and now reappeared. A shoal of Neon Tetra (Paracheirodon innesi) survived a whole summer in the hot mid 1970s and there is a declining population of Australian Swamp-Stonecrop (Crassula helmsii) around the north and east margin of the Pool which with luck may have been wiped out by the recent severe winter. These two certainly look like Red eared Terrapins (now called Trachemys scripta elegans as far as I am aware) and are obviously made of sterner stuff.

They are generalist omnivores and can survive on a wide variety of food which helps them to survive outside their natural range of the southern US and Mexico. They were introduced across the world through the international pet trade [now banned in the EU] as millions of hatchlings in the 1980s to satisfy children’s craving for a Ninja turtle in the house. The children have grown up and so have these long lived reptiles which have out grown their aquaria and been dumped in any locally water body available.

They are unable to breed in the UK and Northern Europe due to temperature so far, but they do breed in Mediterranean climates and have a significant competitive advantage over the native and already declining European pond terrapin (Emys orbicularis) .

These terrapins are considered to be among the world's top 100 most invasive species, but there are no reports of them having had a detrimental effect to the conservation status of any UK species to date. But as they live for 40 – 50 years they just might be able to breed before they die of old age in this period of climate change, so using the precautionary principle I would like to think that we will be able to catch them if the opportunity arises and send them off to Terrapin Rescue. It took 4 years before the opportunity arose to capture the single individual at the Parc Slip Nature Park, and not least because a reasonable numbers of these adult terrapins living to acidic habitats in South Wales, like the Gower Commons, are suffering from a chronic calcium deficiency, which I suppose might hinder their breeding success in any case if we do warm up enough.


Barry Stewart said...

Very interesting stuff Nigel. I notice that there is a report of Great Crested Grebes at Cosmeston having had their eggs robbed by turtles, although the Little Grebes at Broad Pool seem to breed successfully most years.