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BBC (London, UK) 28 March 11 Experts DNA test England's adders to help halt decline
Ecologists are running DNA tests on adders to check their genetic diversity amid fears the UK's only venomous snake is vanishing from the wild.
A recent study found that numbers of the reptile had declined since 2007.
Conservationists believe inbreeding in small, isolated populations could lead to a further decrease in numbers.
Experts from Natural England, the Zoological Society of London and Oxford University are taking swabs from the reptiles at 16 sites across England.
Ecologist Nigel Hand has already carried out health checks and collected DNA samples from five snakes at a Surrey Wildlife Trust site and 27 adders from an area in Norfolk.
Once captured, the reptiles are placed in a plastic tube to measure their length and protect the handler from their bite.
A swab is taken and they are marked before they are released back into the wild.
The DNA is then analysed to see whether larger or smaller populations have different levels of genetic variety.
Jim Foster, of Natural England, said: "With around a third of adder populations now restricted to isolated pockets of habitat, and with only a handful of snakes per sites, they could be especially vulnerable."
It is estimated that there are 1,000 populations of adder in the country with some groups made up of fewer than 10 adults.
Mr Foster said the tests would also help them understand why some adders had been found with abnormalities including malformed scales and missing eyes.
He added: "In the longer term, the last resort option is whether we should move animals between populations, artificially encouraging them to mix."
Experts DNA test England's adders to help halt decline

THE GUARDIAN (London, UK) 28 March 11 Adder abnormalities lead to UK's first genetic survey of snakes - Researchers want to find out if decreasing numbers of snakes caused by urbanisation has led to inbreeding among adders (Damian Carrington)
With a quick dart of the arm, snake catcher Nigel Hand snares his prey and holds the wriggling adder aloft.
The bronze snake, hissing and flicking out its black forked tongue, has been snatched from under its gorse-bush home as part of the first ever genetic survey of the UK's only venomous snake, amid fears that dwindling populations are behind worrying signs of inbreeding, such as missing eyes and deformed spines.
But the young female caught by Hand looks healthy, barring a 3cm-long scar on her back left by a buzzard or a kestrel. She squirms friskily, despite having just emerged from a five-month hibernation, as a bright spring sun shines through the alders and birches that fringe the riverside meadow.
"Adders are living on the edge in more senses than one," says Jim Foster, national reptile specialist for Natural England. They like to live on the margins of open ground and in the shelter of woods, basking in the sun then diving for cover. But habitat loss of heaths and meadows means they are also on the edge in population terms, with at least a third of the 1,000 known populations diminishing. Those smaller groups have fewer than 10 adults and even the bigger clans have just a few dozen.
"We also still have a few problems from people going out and killing them, even though it is illegal," says Foster. He says the dangers of adders are small – the last death from an adder bite was in 1975 – and that attitudes to the snake, also known as the viper, have improved vastly over the years.
Taking a DNA sample from the 50cm-long adder is harmless if undignified, with a small swab inserted into its vent, an opening that doubles as the excretory and genital orifice. "Swabbing the mouth is quite dangerous, so we thought we'd try the other end," explains Foster. Samples are being taken from both small and large populations at 16 sites across the country. Scientists at Oxford University will then compare the samples to see if the smaller clan groups are indeed genetically impoverished.
"These abnormalities are very worrying, but we don't know yet if it is to do with a lack of genetic diversity. That's why this project is essential," says Foster. Studies of rattlesnakes in the US have shown clear links between inbreeding and deformities. Malnutrition and disease are other possible, if still worrying, causes.
The adder project highlights a looming issue for wildlife in the UK: maintaining genetic diversity in isolated populations. "Genetic management is a new field and we have to think about it now in the UK, as our landscape becomes ever more fragmented," says Foster.
The preferred solution is to provide wildlife corridors to allow populations to mix, for example by converting strips of farmland to meadow, or creating a series of glades through overly dense woodland. But this will be impossible at adder sites surrounded by built-up areas. In those cases, individuals will be translocated across the country to reinvigorate the gene pool. It is a last resort, says Foster, but has been done successfully with adders in Sweden and with natterjack toads in the UK.
A small population of the toads in Lincolnshire had become dangerously inbred, Foster explains, so two years ago Natural England introduced toads brought in from Bedfordshire. "The alternative was to let the group go extinct," says Foster.
But translocation does have risks, as the infusion of new DNA can obliterate special genetic adaptations to local conditions.
This happened in the Tatra mountains in Slovakia where mountain ibex from Turkey and Egypt were used as an influx of new blood, but changed the breeding pattern so much the herd became extinct.
Back in the Surrey meadow, the conservationists combing the undergrowth for the next snake to swab are determined to ensure modern DNA technology can play its part in halting the decline of the adder.
"They are a sentinel species – high up in the food chain. So a good healthy adder population will support all the species below them, giving a good, healthy ecosystem overall," says Jamel Guenioui, who manages the Surrey Wildlife Trust site. Adders feed on field voles and lizards, which in turn eat grasses and insects respectively.
Hand points out the extraordinary display known as "dancing adders", which will be seen in the coming weeks as males battle to win mating rights. "It's a wrestling match of strength and stamina, highly ritualised. It's one of the great spectacles of nature in the UK."
"We have lost the wolf, the lynx and lots of other key species," he says. "But, although there are very few of them, we still have this small, beautiful and enigmatic snake."
Adder abnormalities lead to UK's first genetic survey of snakes

THE TELEGRAPH (London, UK) 29 March 11 Should we celebrate or mourn the death of Britain's only venomous snake? (Dr Pete Wedderburn, DVM)
One of the under-rated benefits of living in the United Kingdom is the lack of hazards in our natural environment. There are no scary scorpions, toxic tarantulas, rabies-carrying wildlife nor life-threatening sea creatures. The only venomous wild creature is the adder, or viper. And the news is that even this threat may be on the way out. In fact, scientists are so worried about the dwindling adder population that they’re taking steps to prevent its extinction, including DNA profiling. They’re even considering taking the type of actions to prevent inbreeding and promote genetic diversity that Jemima Harrison would love to introduce for pedigree dogs. Should they bother? Or should we instead be quietly pleased that, as the last adder dies, the United Kingdom will become a marginally safer place?
The last human to die of an adder bite was over thirty five years ago, so the snakes can hardly be seen as a serious public health issue. What about the risk to animals? One person commenting on the Daily Mail article says that “in a warm summer, vets are inundated with people bringing in dogs that have been bitten”. I don’t think that there’s any evidence of that; in areas where adders are relatively common (such as the New Forest), a vet might see a couple of cases a year, which is hardly a tidal wave. Instances of confirmed bites (as in dog yelps, owner sees snake) are far less common that “suspected bites”, which could be caused by other insect stings or allergic reactions of various types. And even when a dog is bitten by an adder, it’s rarely fatal.
So my response is “yes, the population of adders should be looked after”. The preservation of wild animal species is important. When the last member of any species dies, the world becomes a lesser place. Another small but unique piece of genetic code is lost.
To quote an ecology website, many plants and animals may not carry obvious direct benefits, but they “clean air, regulate our weather and water conditions, provide control for crop pests and diseases, and offer a vast genetic library from which we can withdraw many useful items. Extinction of a species could potentially mean the loss of a cure for cancer, a new antibiotic drug, or a disease-resistant strain of wheat. Each living plant or animal may have values yet undiscovered.”
People may not like adders, and they do present a small but significant risk to people and animals using the countryside, but that doesn’t mean that we should stand by and watch them vanish.
Should we celebrate or mourn the death of Britain's only venomous snake?[/