Numbers of Britain’s rarest lizard, the sand lizard, are increasing in parts of southern England - possibly due to climate change.
Sand lizards are only found on heathlands and sand dunes in parts of Dorset, Hampshire, Surrey and a few other counties. They are considered rare and threatened in the UK, and are also endangered across much of their European range.
Recent surveys by reptile ecologists have identified sand lizards in some unusual locations. They are always near to existing populations, but the new populations are thriving in habitats that wouldn’t traditionally suit them, such as development sites, railway lines, derelict brownfield sites and roadside verges. This spread may reflect warmer summers allowing more successful breeding.
Dr Chris Gleed-Owen, a consultant ecologist from CGO Ecology Ltd said, “Sand lizards are increasingly turning up in the most unexpected places, including rubble piles and weedy building sites. It’s no laughing matter for a developer, as work has to stop until a licence is obtained and the lizards are re-homed.”
For many years, sand lizards have been declining towards extinction. Over the last 200 years, they have lost around 80% of their habitat in southern England. However, recent conservation work is helping them to recover.
Intensive work has been going on for many years to protect sand lizard habitats, and to start new populations. Conservation charity ‘The Amphibian and Reptile Conservation Trust’ manages many nature reserves, and has reintroduced sand lizards to more than 50 places from Cornwall to Kent.
But previous conservation work has mainly focused on nature reserves and other protected sites. It now seems that sand lizards are thriving where they are least expected, on marginal and brownfield sites.
Dr Gleed-Owen continued, “These new locations tend to be contiguous with heathland or other known habitats, and they are often linear sites acting as colonisation corridors. This is great news for sand lizards because it reverses some of the fragmentation that has been isolating populations for decades.”
For some time, experts have been suggesting that climate change might be benefiting sand lizards. Warmer summers have meant that females can now lay two clutches of eggs every year, instead of one.
The story is not all rosy for sand lizards though; they are still highly threatened by habitat loss. Arson and accidental fires can wipe out huge areas of heathland, and this spring has seen some dramatic losses already. To add to the problem, encroachment from trees and scrub shades out heathland habitat, and threatens sand lizard populations unless a constant programme of vegetation control is in place.
Sand lizards (scientific name: Lacerta agilis) are normally only found on sandy heathlands and coastal sand dunes, because these habitats provide warm microclimates.
Sand lizards are Britain’s only egg-laying lizard, and require bare patches of sand for breeding. Heavily-pregnant females dig burrows in sunny locations in late May, lay about 6-10 eggs at the bottom, and backfill them. The young hatch around 7-10 weeks later. They are fully self-sufficient, and reach maturity in 3 to 5 years.
Sand lizards have lost around 80% of their heathland and sand dune habitat due to urban development, quarries, forestry, agricultural intensification, golf courses and other developments.
Elsewhere in their European range, where summers are warmer than the UK, sand lizards are able to occupy a wider range of habitats. Their expansion into different habitats in the UK could be a signal of warmer climate here.
Sand lizards and their habitat are protected by European law, via the Habitats Regulations 2007 in the UK. They are also protected by the Wildlife and Countryside Act 1981.
Developments affecting sand lizards or their habitat require the involvement of an ecologist to supervise mitigation efforts. This often involves forward-planning in order to catch and move the lizards, under an ‘EPS licence’, to a specially-prepared site elsewhere.
Sand lizards are found in the following counties of England and Wales: Cornwall, Devon, Dorset, Hampshire, Surrey, Berkshire, West Sussex, Kent, Merseyside, Gwynedd, Denbighshire, and Flintshire. An isolated population also exists on the Scottish island of Coll. There are plans to reintroduce them to other counties.