Experts to perform health check on England’s only venomous snake
28 March 2011
Snake experts from Natural England, Zoological Society of London (ZSL) and Oxford University have teamed up to perform a vital health check on Britain’s only venomous snake, the adder, following worrying declines.
With its iconic zig-zag markings, the adder was once a common sight in large parts of the British countryside. But in the last decade it has slipped into decline, with surveys suggesting a third of remaining adder populations may comprise fewer than ten adults.
Scientists believe this is down to the disappearance, degradation and fragmentation of habitat, resulting in smaller and more isolated populations of this enigmatic reptile.
It is feared that if these smaller populations, particularly in the English Midlands, are not able to maintain a healthy level of genetic diversity, their resilience to disease will be reduced and a concentration of genetic defects could occur, leading to local extinctions.
For the first time, a team of snake experts are heading into the undergrowth to obtain genetic samples from adders. This simple, harmless test involves taking a DNA swab, which can be used to determine current levels of genetic diversity.
Whilst the scientific procedure is risk-free for the snakes, the experts will be taking every safety precaution necessary to avoid being bitten – this is not something that should be tried at home.
Dr Trent Garner, Senior Research Fellow at ZSL’s Institute of Zoology said: “Genetic diversity has been shown to be a key component for successful adder populations in Sweden and Hungary, but has yet to be studied in the UK. Our goal is to provide the first insights into how population size and isolation may be related to genetic diversity of the UK’s adders.”
Jim Foster, reptile specialist for 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 site, they could be especially vulnerable. As we have seen with natterjack toads, populations that are small and isolated can start to decline purely through genetic effects. This ground-breaking study will see if adders are suffering a similar plight.
“Fortunately, if there are problems we still have time to deploy a number of conservation remedies. Habitat restoration and the creation of wildlife corridors will help get these snakes back on the move. We may even consider moving adders between populations, to artificially promote “gene flow” - although that carries risks and we’d need to look more closely at the genetics results before proceeding.”
Dr Tobias Uller of Oxford University’s Department of Zoology said: “When populations become small and isolated, with it comes the risk of expression of harmful genetic variants that normally remain ‘hidden’ in larger populations. Loss of genetic variation may also compromise the population’s ability to evolve – a problem that is particularly acute when habitats change rapidly or if a new disease emerges.”
Notes to editors:
For information, photographs and interviews contact:
Natural England: Beth Rose, senior press officer: 0300 060 1405 / 07900 608 052 beth.rose@naturalengland.org.uk Zoological Society of London (ZSL): Victoria Picknell, press officer: 020 7449 6361 victoria.picknell@zsl.org
The adder conservation genetics project:
The adder Vipera berus is one of three native snake species in England (the others are the grass snake and smooth snake). The last national analysis showed worrying trends toward the isolation of populations, with declines in adder numbers recorded at around a quarter of sites, and more local extinctions among adders than other reptiles. A survey published by Amphibian and Reptile Conservation earlier this month found adders to be present in only 7% of surveys nationally. The adder is listed as a national priority species in the UK Biodiversity Action Plan.
The data show that large populations of adders still thrive on major tracts of open habitat. The conservation concern is mainly with small, isolated sites. This new project aims to see if there is a genetic component to the problem. Studies on some other species show that smaller populations can decline when the animals cannot disperse to and from other sites, to maintain genetic diversity. The suspicion is that English adders could be at risk for this reason, but without proper genetic research, we simply cannot say if that is the case.
The project gathers together the specialist reptile knowledge of the Institute of Zoology and the University of Oxford, with the conservation experience of Natural England. Volunteers working with the Amphibian and Reptile Groups of the UK (ARG-UK), who spend countless hours monitoring reptiles, will guide researchers to key adder sites. The plan is to compare the genetic variation of adders at large sites with that at small, isolated sites.
In the field, an expert will capture the adders taking special care to ensure their welfare, and to avoid being bitten. Nigel Hand of the Institute of Zoology will do this, having had in-depth experience of adder handling, for example through radio-tracking projects. The team emphasises that no one else should attempt to capture adders, unless part of a properly planned project with full risk assessment. Although life-threatening reactions to adder bite are extremely rare, it is still a serious medical condition and no one should take unnecessary risks. In addition, adders can be injured easily by untrained handling.
Once restrained, a DNA sample will be taken by carefully inserting a swab into the adder’s vent (the genital and excretory opening in snakes). The swab collects skin cells, which are then subject to genetic analysis in the laboratory. We hope to have the results available this autumn.
1. About Natural England
- Natural England is the government’s independent advisor on the natural environment. Established in 2006 our work is focused on enhancing England’s wildlife and landscapes and maximising the benefits they bring to the public.
- We establish and care for England’s main wildlife and geological sites, ensuring that over 4,000 National Nature Reserves and Sites of Special Scientific Interest are looked after and improved.
- We work to ensure that England’s landscapes are effectively protected, designating England’s National Parks, Areas of Outstanding Natural Beauty and Marine Conservation Zones, and advising widely on their conservation.
- We run England’s Environmental Stewardship green farming schemes that deliver over £400 million a year to farmers and landowners, enabling them to enhance the natural environment across two thirds of England’s farmland.
- We fund, manage, and provide scientific expertise for hundreds of conservation projects each year, improving the prospects for thousands of England’s species and habitats.
- We promote access to the wider countryside, helping establish National Trails and coastal trails and ensuring that the public can enjoy and benefit from them.
For further information about Natural England contact:
The National Press Office on 0845 603 9953/ press@naturalengland.org.uk / out of hours 07970 098 005 / www.naturalengland.org.uk
2. About ZSL
Founded in 1826, the Zoological Society of London (ZSL) is an international animals and their habitats. The Society runs ZSL London Zoo and ZSL Whipsnade Zoo, carries out scientific research in the Institute of Zoology and is actively involved in field conservation in other countries worldwide. For further information please visit www.zsl.org
3. Oxford University
For more information visit: www.ox.ac.uk
