Coastlines



 

Nature and Wildlife - Habitats and Species

The Sand Lizard
Lacerta agilis

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Sand lizard in dune habitat The sand lizard (Lacerta agilis) is a rare and endangered reptile species. Its range stretches from Russia in the east to France and Britain in the west, with scattered populations surviving in dry heathlands and coastal sand dunes. It has suffered greatly from habitat loss and the Sefton Coast is now one of its last British strongholds. Males have vivid green flanks and both sexes are significantly larger than the common lizard. The sand lizard is protected by the Wildlife and Countryside Act (1981) against sale, killing and injury.

HISTORY

The sand lizard used to be much more common even fifty years ago than it is now, but it was probably never very widespread within historical times. Very little is known about its history in Britain before the 19th century. It presumably arrived in Britain some time after the last Ice Age ended about 11,000 years ago. During the freezing conditions of the Ice Age, the sand lizard and other warmth-loving species would have been restricted to 'refugia' in southern Europe. Only when the ice sheets melted did they make their way northwards into Britain. This must have happened before Britain was separated from the continent by sea level rise, about 8,000 years ago. The population on the Sefton Coast is now isolated from the other surviving populations in southern Britain, but at one time they must have been more connected - either as a continuous spread across central England or along a coastal sand dune strip. There is no record of sand lizards from archaeological sites so it is difficult to know anything about its history in Britain.

DESCRIPTION AND HABITS

Adult sand lizards reach about 20cm in length with a more robust build than the smaller common lizard. Sand lizards also have a much bolder body pattern, with dark blotches called 'ocelli' which have a pale dot in the middle of each, like an eye. Males develop bright green flanks within weeks of emerging from hibernation in the Spring and have broader heads than females. Females are generally brown with dark and light ocelli. As a reptile the sand lizard is 'ectothermic' which means it gets its warmth from the surrounding environment and basking in direct sunlight. It reproduces by laying eggs which need sufficient summer warmth to incubate. All reptiles hibernate during the winter in Britain, but the weather doesn't have to be as warm as most people think for them to be active. In the Spring, on a sunny day with no wind, as soon as the temperature reaches about 12 degrees centigrade sand lizards come out to soak up the sun. They climb up vegetation or lie out in open sand, but never very far from the safety of vegetation. You are less likely to see them on a hot day in the Summer as they will be warm enough by 10 or 11am, after which they go off hunting, deep in the vegetation. Sand lizards can live for 10-12 years, becoming sexually mature after two or three years. Females lay about 6 eggs and the hatchlings have to fend for themselves immediately, and avoid being eaten by other sand lizards! Generally sand lizards eat a variety of invertebrates including spiders and grasshoppers.

Female sand lizardFemale sand lizard basking in remains of fire. Copyright Paul Wisse

A YEAR IN THE LIFE OF THE SAND LIZARD

During the Winter, sand lizards remain in a state of suspended animation (hibernation), in burrows under the ground. They cope quite easily with the British winter as it is considerably warmer than in Russia, where sand lizards also live. When sunny Spring days start to reach 10 or 12 degrees centigrade, sand lizards start to emerge from hibernation. The males come out first, followed by the females a few weeks later. At first the males do not have their characteristic green sides but this develops after a few weeks. On the warm south coast of England, sand lizards emerge in March or even February, but on the Sefton Coast most probably hibernate until April.

Activity increases throughout Spring with males feeding and basking to reach physical condition. Mating then takes place and territorial males can sometimes be seen fighting or chasing rival males away. About 6 weeks later, females excavate burrows in open sand, sometimes making several 'test burrows' before they dig a suitable one. When they are happy with the burrow they've excavated they lay about 6 eggs and fill it in afterwards. Egg-laying normally occurs around June, but recently in southern Britain females have been laying earlier and even laying a second clutch later in the Summer.

Around August, after incubating in the sand for about 10 weeks, the eggs hatch and the juveniles clamber to the surface. They measure about 60mm in length and are dark brown with small white spots. They hunt, bask and look after themselves like miniature versions of adults.

By October, the weather is usually deteriorating so that not many days are warm or sunny enough for sand lizards to be out basking. Some animals may be seen throughout the month, especially the new juveniles, but most will already be heading underground for another Winter.

CONSERVATION

The sand lizard is just one of many species in Britain that has suffered greatly from a century of building, road construction, scrub encroachment, afforestation, quarrying and fires. It has fared particularly badly because it is so restricted in its distribution and its requirements. Britain is at the edge of its range and in the cool British summer it can only thrive in particular habitats: dry heathlands with sandy soil and sand dunes. With all these factors together, and the few remaining populations of sand lizards becoming smaller and more isolated from each other, the sand lizard has become an endangered species. The Government's Biodivesity Action Plan includes the sand lizard as a priority species however, and a lot of effort is being put into its conservation.

On the Sefton Coast, the sand dunes are still threatened by development (house-building etc) and by fires whether deliberate or accidental. Scrub encroachment where dunes have become stabilised for a long time is also a problem, and a lesser problem is direct disturbance by people.

Survey and monitoring work is being carried out to find out how far the sand lizards are spread around the Sefton coast (including golf courses and railway embankments!) and to see how well they are doing. Similar work is going on throughout the sand lizard areas of southern Britain. Conservation efforts are centred on preserving the future of existing sand lizard habitats, creating new habitat for (e.g. by clearing pine plantations) and releasing captive-bred sand lizards into areas where they have become extinct.

ORIGINAL TEXT PROVIDED BY CHRIS GLEED-OWEN, THE HERPETOLOGICAL CONSERVATION TRUST