Here is an article I wrote for my old blog. I’ve gone through and checked for mistakes and added some bits:
Green lizard is the common name that refers to two species that were formally one (Lacerta viridis). The new species, the western green lizard (Lacerta bilineata), is now considered separate from the eastern green lizard (Lacerta viridis) (Amann et al. 1997). They are native to the UK in the sense that they are found on Jersey, and fossils have shown they were once present in the UK, but all recent non-Jersey records seem to originate from introductions, so the species is not considered native in Britain, away from Jersey.
Green lizards are characterised by its size the green body with varying amounts of blue on the head, usually around the throat. It is the biggest species of lizard found in the UK, adults reaching 30cm long, with the tail comprising half of the overall length. They are native to mainland Europe including France, Italy and most of South Eastern Europe, being more common in the southern part of its range.
Here it is found in many habitats with suitable basking spots including woodland, heathland and river banks. Those living on river banks are known to jump into the water and swim to safety or bury themselves in soft mud when disturbed.
In the northern part of its range it hibernates in winter, as it does in the UK population. It preys on insects, other reptiles, bird chicks and eggs, small mammals and some fruit. Reproduction is by egg laying, where 4-20 eggs are laid in June and hatch 2-4 months later (Gibson, 2005).
The first non-Jersey record of a ‘green lizard’ was 1768 in Surrey, though these are reckoned to be native male sand lizards (Lacerta agilis) or green colour morphs of the introduced common wall lizards by Lever (2009) as were other records of green lizards in the late 19th and early 20th centuries in Dorset and Devon. It has however been suggested that some of these early records may actually be Green lizards (Downes, 1994 + Naish, 2006).
The first definite records of Green lizards in the UK are from 1872, when a number of green lizards were set loose in Ynysneuadd woods in Wales, with the first English record was in 1899 in St. Lawrence on the Isle of Wight when 230 green lizards were released and they persisted until 1936 (Lever, 2009).
Lever (2009) also reports on introductions in Haslemere, Surrey (1905-10), Paignton, Devon (1937, persisting to 1946), and short lived introductions in Sittingbourne, Kent (1962) and Gloucestershire (1960s).
The above records may be of either of the two species but there is no way of knowing as they were still regarded as them same species at the time.
All of the previously mentioned colonies have not persisted to today but there is one on the UK mainland that appears to be a viable, the colony at the Boscombe cliffs in Dorset. Here they are found along side another non-native, the Common Wall Lizard (Podarcis muralis), and the native common or viviparous lizard (Zootoca vivipara)(Lever, 2009). The colony was discovered in 2002 and is believed to have been deliberately and illegally introduced and was done using lizards from Northern Italy near the Slovenian border, as shown by DNA analysis (Deichsel, Gleed-Owen & Mayer, 2007).
A study by Mole (2008) has many insights into the colony, pointing out how the colony has spread since 2002 and the impact it has had or may have on the native lizards. The study found that the numbers of common lizards appear to have declined within the colony and they were more common on edges, which suggests the alien species are having a negative effect on the native common lizard. Even more worrying is the proximity of a sand lizard (Lancerta agilis) population to this spreading colony, as this species is endangered in the UK, and the invasion of non natives could cause a decline in their numbers.
Another sad case of an alien species causing a decline in a native species, and another that, due to the dangerous nature of the cliff face terrain they inhabit, that will be impossible to remove without serious impact to native species ([URL=http://www.lacerta.de/Themengebiete/Verschleppung%20und%20Aussetzung/images/Bournemouth/Simon_Mole_2008.pdf]Mole, 2008[/URL]).
As for the future of this species in the UK, Mole (2008) suggests that the two limiting factors are suitable habitat and climate, the latter having an effect on recruitment (i.e. reproduction success and juvenile survival rates). There is suitable habitat beyond the boundry of the Boscombe colony which suggests they will continue to spread and both Mole (2008) and Lever (2009) suggest with the warming climate, conditions for green lizards in the UK will only improve.
So based on the negative impact of the common lizards and a more favourable climate increasing the likelihood of an introduction flourishing, possibly at the expense on native animals, further releases of green (and wall) lizards should be prevented. To quote Mole (2008) “Some introductions are neutral, most die, but it is often too late for native species by the time invasive species are established. Is it worth the risk?”
If you are interested in green lizards in the UK I would recommend the study by Mole and heading [URL=http://darrennaish.blogspot.com/2006/04/hunting-green-lizards-in-dorset-new.html]here[/URL] which is a post on Darren Naish’s excellent blog and includes a trip to the Boscombe colony itself as well as more info on the subject. As for the captive Green Lizards Ive photographed, they can be found at the [URL= http://www.wildwoodtrust.org/]Wildwood trust[/URL], Near Canterbury in Kent.
Amann, T., Rykena, S., Joger, U., Nettmann, H. K. & Veith, M., 1997, Zur artlichen Trennung von Lacerta bilineata Daudin, 1802 und L. viridis (Laurenti, 1768). Salamandra 33, 255-268.
Deichsel, G., Gleed-Owen, C. P. & Mayer, W., 2007, Lacerta bilineata (Western Green Lizard) and Podarcis muralis (Common Wall Lizard) United Kingdom, Dorset. Herpetological Review 38 (1). 100-101.
Downes, J. 1994, Green lizards in Devon and Dorset? Animals & Men 2, 22-23.
Gibson, C., 2005, Pocket Nature: Wild Animals Doring Kindersley
Lever, C., 2009, [i]The Naturalized Animals of Britain and Ireland[/i], New Holland Publishers Ltd.
Mole 2008, An Investigation into the Effects of the Western Green Lizard (Lacerta bilineata) and the Common Wall Lizard (Podarcis muralis) Introduced onto Boscombe Cliffs, Dorset, U.K. [URL=http://www.lacerta.de/Themengebiete/Verschleppung%20und%20Aussetzung/images/Bournemouth/Simon_Mole_2008.pdf]here[/URL]
Naish, D., 2006, Hunting Green lizards in Dorset: new aliens or old natives?, http://darrennaish.blogspot.com/2006/04/hunting-green-lizards-in-dorset-new.html