Today's DARN task to create bare-ground patches for sand lizard egg-laying was a great success. A merry band of seven volunteers spent the morning digging sand patches on Turbary Common heathland nature reserve managed by Bournemouth Borough Council. Patches of bare sand are essential for female sand lizards to lay their eggs in at this time of year. They dig short tunnels in firm sand in sunny locations. Much of Turbary Common has become too dominated by western gorse that leaves little bare ground. In turn, sand lizard numbers have declined as a result of poor breeding success.

We dug a total of 30 patches today, generally around 1m in size. From 9am til 12pm, we worked our way across all the heathland compartments that are known to support sand lizards. After clearing vegetation and turf with mattocks and loppers, we dug or scraped down to firm sand with garden spades. Sand lizards have suffered dramatic declines in recent years in nearly all areas where they are present, so hopefully today's task will start reversing the decline almost immediately. This year's warm spring has meant that the end-of-May egg-laying season has started early. We found two 'test burrows' (shallow preliminary diggings by egg-laden female sand lizards) on an existing patch of bare sand beside an abandoned fox earth. We hope that the new sand patches might be used by sand lizards over the next couple of weeks, and we will monitor this.

Today's energetic volunteers were: James Boyland (Bournemouth Borough Council), Jonathan Crewe, Stephanie Clark & Chris Gleed-Owen (DARN volunteers), Darren Millward & Tina Ballard (Stour Valley Volunteers), and Brian Whitehorn (local reptile photographer). See the photos posted on this site's Photo Gallery.

A research project is under way to investigate whether populations of Britain's only venomous snake - the adder (Vipera berus) - are suffering from genetic bottle-necking. Many conservationists believe adders are declining rapidly in Britain. Habitat degradation and fragmentation are factors often cited, but there may be genetic problems too. 

Adders are susceptible to localised threats such as scrub removal or hibernaculum destruction that can wipe out whole populations. Localised damage is often the result of well-meaning conservation work by land managers targeting other wildlife. These local extinctions add up nationally to 'death by a thousand cuts'.

Adders are not very effective at spreading and colonising new areas, and when they undergo a localised extinction, they rarely recover. Fragmented and isolated populations could then face genetic problems. Low genetic diversity in isolated populations can lead to 'inbreeding depression', making populations vulnerable to birth defects, low fertility, and general lack of fitness.

Researchers at London's Institute of Zoology are working with Oxford university and Natural England to study adder populations from around England this spring. Each adder is swabbed to take a DNA sample, and examined to measure its genetic profile. The researchers are sampling two types of population: smaller ones with fewer than 10 individuals, and larger ones with 20-30 individuals.

The project's fieldwork and staff costs are funded by Natural England and the other research partners. The laboratory analysis costs are being funded by a £1000 grant from the British Herpetological Society. Nigel Hand, a well-known herpetologist from Herefordshire, is the project officer. He is currently busy travelling the country, catching and swabbing adders.

To read more about the project, see the following news item: http://www.guardian.co.uk/environment/2011/mar/28/dwindling-adder-numbers-genetic-survey?CMP=twt_fd.

Amphibian and Reptile Conservation is once again running training days for participants in NARRS surveys. They are open to all volunteer surveyors who can spare a few hours here and there over the spring, to survey a site within their own randomly-allocated 1km square.

Location: Furzebrook Village Hall, Purbeck, Dorset
Dates: 4^th – 5^th of April 2011
Cost: £10 to cover materials and basic refreshments
Contact: johnw.wilkinson@arc-trust.org to book a place, and for details.

Our group took part in the national Chytrid Survey 2011 (aka "the Big Swab") last week. DARN members Jonathan McGowan, Phil Smith, Alan Uren and Chris Gleed-Owen visited a pond in Puddletown Forest (with permission kindly arranged by Mark Warn of the Forestry Commission). The pond supports a large population of palmate newts, as well as common toads and common frogs.

The survey protocol required the participants to catch 30 amphibians from one pond (not to include common frogs) and swab their rear undersides with medical swabs. The swabs will be tested for chytrid DNA as part of a project coordinated by Freya Smith at the Institute of Zoology, to discover whether the infectious disease is spreading in the UK.

At the Puddletown Forest pond, extensive netting failed to catch any toads (or frogs), but a full quota of 30 palmate newts was caught easily in only three net sweeps! The newts were individually bagged with water and air, and then swabbed and released over the next hour.

As reported here previously, the spread of chytrid fungus has had devastating affects on amphibian populations across the world, and many herpetologists fear the possible impacts on populations in the UK. Chytrid is already known to affect natterjack toads, one of our rarest species. High mortality was discovered in captive-bred natterjacks in Cumbria in 2006 due to chytrid infection.

See our chytrid swabbing photos in the Gallery.