The following is the British Deer Society’s official statement on the Dolman Report, issued 7 March 2013 in “Deerbytes”, the BDS online newsletter:

The British Deer Society welcomes good science. It has yet to read Dr Dolman’s report in full, but has seen the sensationalist headlines calling yet again for an increased cull of deer across the UK.

The Society is wary of headlines such as 750,000 deer to be culled annually – this is not well-justified and sounds as if it offers rather an arbitrary figure, not one based on a very scientific approach.  Further, as a percentage of the wider UK deer population, the BDS will be interested to see the methodology behind an estimation of 1.5m deer in the UK, which is 25% lower than a recent estimate by the Deer Initiative of deer in England and Wales.

The British Deer Society acknowledges that there are areas within the UK where there are far too many deer – such as the Arne Peninsula (where recent active management has more recently been effective in reducing densities and associated impacts), Ashdown Forest, and Thetford Forest where this research appears to have been carried out – but suggests that such ‘hotspots’ of high density are not representative of the wider countryside.

Extrapolation of more general levels of deer impact on biodiversity at a national level from results obtained within a study area of perhaps atypically high deer density may lead to somewhat unsafe conclusions about general impact levels.

The assertions about impacts on biodiversity detract from the main message of Dr Dolman’s study:  in demonstration of source-sink movements at a landscape scale in response to management.

The British Deer Society is very supportive of active deer management, directed towards ensuring that deer numbers are maintained at densities that are in balance with their habitat and strongly supports a call that co-ordination of such management at a landscape level is to be encouraged.

The British Deer Society welcomes Dr Dolman’s references to deer in urban and peri urban environments, where there is a serious problem developing with growing deer populations in areas where practical management is very difficult.

“50% cull ‘necessary to protect countryside”

Around half of the UK’s growing deer population needs to be shot each year to stop devastation of woodlands and birdlife, a group of scientists says.

A study published in the Journal of Wildlife Management says this would keep numbers stable.

The deer population is currently estimated at around 1.5 million. The researchers from the University of East Anglia suggest harvesting the animals for meat to make a cull ethically and economically acceptable.

The Royal Society for the Prevention of Cruelty to Animals (RSPCA) commented that any cull must be carried out in a humane and controlled way and be supported by “strong science”.

There are now more deer in the UK than at any time since the last Ice Age. In the absence of natural predators deer populations are continuing to expand, threatening biodiversity and causing road traffic accidents and crop damage, say researchers. Britain has a total of six deer species, four of which were introduced since Norman times. The most recent newcomer is the Chinese water deer, which became established in the wild in the 1920s.

Dr Paul Dolman, ecologist at the University of East Anglia and lead author [of the Report], said: “We know deer are eating out the… vegetation of important woodlands, including ancient woodlands. Deer are implicated as the major cause of unfavourable conditions in terms of woodland structure and regeneration. There is evidence that deer reduce the number of woodland birds – especially some of our much loved migrant birds species like Blackcap and Nightingale, and resident species like Willow Tit. We have a problem. What we are advocating isn’t removing deer from the countryside – what we are advocating is trying to get on top of the deer population explosion”

Dr Dolman led a census of roe and muntjac deer populations across 234 sq km (90 sq miles) of woods and heathland in Breckland, East Anglia.

The researchers drove more than 1,140 miles at night using thermal imaging cameras to spot deer and provide an accurate estimate of their true numbers.

The results indicate that existing management strategies are failing. Although deer numbers appeared stable in the area, this was only because thousands of the animals were being pushed out into the surrounding countryside each year.

The new research suggested that only by killing 50% to 60% of deer can their numbers be kept under reasonable control. Such a cull would be on a far greater scale than the 20% to 30% rates recommended previously. With total deer numbers conservatively estimated at about 1.5 million, it could result in more than 750,000 animals being shot every year.

In a statement, the RSPCA said it was “opposed in principle to the killing or taking of all wild animals unless there is strong science to support it, or evidence that alternatives are not appropriate. Even if a cull is supported by science, it is very important that it is carried out in a humane and controlled way. Any decision to carry out a cull must be taken on a case by case basis based on the specific issues which impact a specific area. We don’t believe this should be rolled out in a uniform way across the whole country. It is certainly not a case of one size fits all.”

The Deer Initiative (DI), which is dedicated to a sustainable, managed deer population in England and Wales, has carried out research into how a cull might be carried out. They say that data on deer numbers and those culled need to be continually reviewed to assess whether culling levels need to be adjusted.

But it says that one-off, heavy culls, followed by little or no culling, never achieve a sustained drop in numbers. Reduction culls need to be substantial and usually need to run over a number of years to be effective. They must then be consolidated by following with a realistic maintenance cull.

Dr Dolman said: “We are not killing something and then incinerating the carcass – what we are talking about is harvesting a wild animal to supply wild free-ranging venison for our tables – for farm shops, for gastro pubs.

Trevor Banham of the Forestry Commission: “Numbers have got out of hand [but] what we are advocating isn’t removing deer from the countryside – what we are advocating is trying to get on top of the deer population explosion and try to control the problems that are being caused. And in a way, [venison] provides a sustainable food source where you know where it comes from, you know it is ethically sourced, you know it is safe to eat, and that puts food on people’s tables. As much as I love deer, to be a meat eater but then to object to the culling and harvesting of deer seems to be inconsistent.”

Previous culling estimates have been lower. The Deer Initiative had previously said that maintaining a static population will require a cull of at least 20% of the population for the larger species (red, fallow, sika), and a cull of around 30% of the population for roe, muntjac and Chinese water deer.

Peter Watson, director of the DI, commented: “The DI welcomes any research that gives us a better understanding of wild deer populations and their impacts. We were happy to support this work by UEA and will look at the evidence to see how it should affect our Best Practice Guidance. Our aim is promote a sustainable wild deer population that is in balance with the habitat. It is for local landowners to examine the evidence and decide how best to respond to the UAE report.”

But he added that this was a single study on two species (out of six) that could not be extrapolated to the whole of the UK, therefore suggesting a cull of 750,000 was not valid. He also said deer had to be managed at a landscape-scale that reflected the ecology of the deer and not man made ownership boundaries.

(From BBC News Science & EDnvironment website, www.bbc.co.uk/news/science-environment-21688447).

The following commentary on the Dolman Report appeared in the Guardian newspaper on Thursday 7 March 2013:

Deer culling on massive scale backed by expert

New research shows that only by killing 50% to 60% of deer can their numbers be kept under reasonable control. Culling on a massive scale is necessary just to keep the exploding deer population at its current level, research shows.  Experts are urging all-out war on deer, which could see close to a million animals being shot each year in the UK.

Culling on a massive scale is necessary just to keep the exploding deer population at its current level, they say. The call to arms was made after new research showed that only by killing 50% to 60% of deer can their numbers be kept under reasonable control. his is slaughter on a far greater scale than the 20% to 30% culling rates recommended before. With total deer numbers conservatively estimated at about 1.5 million, it could result in more than 750,000 animals being shot every year.

Deer are said to be having a devastating effect on woodland, damaging farmers’ crops, causing road accidents and threatening a danger to public safety in urban areas.

Shooting by trained and licensed hunters is the only practical way to keep their populations in check, according to Dr Paul Dolman, from the University of East Anglia. “I don’t think it’s realistic to have wolves and brown bears in rural England,” he said at a news briefing in London. “In the absence of natural predators, the only way to manage them is to shoot them.”

Although they were kept on private land belonging to the nobility, native wild deer were virtually unknown in England for 1,000 years until their re-introduction by the Victorians. Today, there are more deer in the UK than at any time since the ice age. Although it has been suggested that they could number more than 1.5 million, no one knows for certain how many there are. Each year more than 14,000 vehicles are severely damaged and about 450 people injured or killed on British roads as a result of collisions with deer. Deer strip woodland of wild flowers, brambles and shrubs, and disturb the ecology to the point that native birds are lost. The fact that nightingales are now so rare is largely blamed on deer.

Britain has a total of six deer species. Roe deer and red deer are the only two species native to the UK. Four others have been introduced from abroad since Norman times. The most recent newcomers were the muntjac deer and the Chinese water deer, which became established in the wild in the 1920s. Expanding areas of woodland surrounded by farms, together with the lack of natural predators, have provided perfect conditions in which deer can flourish. Like foxes, deer are now starting to feel at home in urban environments, said Dolman.

“Studies have been done in Sheffield that show roe deer living in cemeteries,” he said.

“Muntjac deer will move into private gardens and allotments. Fallow deer are wide ranging – they live in woodland but come in to feed. There are housing estates in London where they’ve been known to graze on lawns in the evening.

“There have been no accidents yet but it’s only a matter of time. These are large animals with sharp antlers. If you had one cornered in a school playing field, it could be nasty.”

Dolman led the first full-scale census of roe and muntjac deer populations across 234 square kilometres (145 miles) of woods and heathland in Breckland, East Anglia. The researchers drove more than 1,140 miles at night using thermal imaging cameras to spot deer and provide an accurate estimate of their true numbers. The results, published in the Journal of Wildlife Management, indicate that existing management strategies are failing.

Although deer numbers appeared stable, this was only because thousands of the animals were being pushed out into the surrounding countryside each year. Culling 53% of the muntjac and 60% of the roe deer each year would only be enough to stop their populations growing, said Dolman. Reducing deer numbers would require even more killing. The same culling levels were likely to be required in other parts of the country.

“Deer populations are going through the roof,” he said. “We’re calling for a very large increase in the magnitude of deer culling.” Darting deer with contraceptives to stop them reproducing was not a practical solution, he argued. It did not resolve the immediate problem and meant venison might be tainted with potentially harmful drugs. It was up to landowners such as the National Trust to organise the culling with support from the Department for Environment, Food and Rural Affairs. Culling would have to be carefully regulated and only carried out by trained stalkers. The result could be a welcome supply of fresh, healthy meat, said Dolman.

“We’re talking about putting venison steaks on your family table or eating venison at gastropubs,” he added. “If we shifted part of our diet to deer it wouldn’t be a bad thing.”

Allowing deer numbers to expand unchecked until their populations crashed would have “consequences a lot crueller than culling”, he maintained.

“Current approaches to deer management are failing to control a serious and growing problem, according to new research by the University of East Anglia.

Researchers drove more than 1140 miles at night and used thermal imaging and night vision equipment to quantify the population of roe and muntjac deer in a unique study spanning the border of Norfolk and Suffolk. The results, published today (7 March 2013) in the Journal of Wildlife Management, show for the first time that present management efforts are not enough to stop populations spreading out of control. 

There are more deer in the UK than at any time since the ice age. In the absence of natural predators, populations are continuing to expand – causing a serious threat to biodiversity, as well as road traffic accidents and crop damage.

The research team investigated the numbers, sex ratio and fertility of roe and muntjac deer across 234 km2 of forested land and heathland in Breckland, East Anglia, to measure the effectiveness of deer management. It is the first time that such a landscape-scale study has been carried out in Europe and the first time that control efforts have been compared to known numbers. They found that while deer management appeared to control numbers at a stable level, this was only because thousands of deer are ‘pushed out’ to the surrounding countryside each year, helping drive the further spread of deer.

In the Breckland study area, researchers identified a necessary cull of 1864 muntjac from an estimated population of 3516 (53 per cent) and 1327 roe deer out 2211 (60 per cent) just to offset productivity, with greater numbers needing to be culled if populations are to be reduced. 

These figures greatly exceed previous cull recommendations for muntjac (30 per cent) and roe (20 per cent). 

Lead researcher Dr Paul Dolman, from UEA’s school of Environmental Sciences, said: “Deer management is often based on guesswork. This is the first time that a population has been quantified and studied in terms of how the deer are breeding – to measure the effectiveness of deer management.

Dr Kristin Wäber, who conducted the study while a PhD student at UEA, said: “Native deer are an important part of our wildlife that add beauty and excitement to the countryside, but left unchecked they threaten our woodland biodiversity. Trying to control deer without a robust understanding of their true numbers can be like sleepwalking into disaster. To effectively reduce and stabilise the population establishing numbers is vital. 

“In Thetford Forest, despite an active programme of professional management culling thousand of deer, the numbers culled did not offset productivity. It is likely that this is happening in other landscapes across much of England. This is a particular problem for non-native invasive species like muntjac.

“In recent years people have become more and more concerned about the impacts deer are having in North America, Britain and elsewhere in Europe. Increasing deer populations are a serious threat to biodiversity – particularly impacting on woodland birds such as migrant warblers and the nightingale. 

“They also carry diseases such as Lymes, and if numbers are not properly managed, they can cause damage to crops as well as road traffic accidents. To help control carbon emissions the government has set targets to increase woodfuel production, but this will be hard to achieve when woodlands are under so much pressure from deer. 

“Current approaches to deer management are failing to contain the problem – often because numbers are being underestimated. Cull targets are often too low. This research shows that an annual cull of 53 per cent for muntjac and 60 for roe deer is necessary to curb their continuing increase and spread.”

A scholarly article in the latest issue of the Journal of Wildlife Management (published online 7 March 2013) appears to call for a massive cull of wild deer throughout Britain and has attracted a range of responses from deer, forestry and agricultural interests. The article is entitled “Achieving landscape-scale deer management for biodiversity conservation: The need to consider sources and sinks” and is authored by Kristin Wäber, Jonathan Spencer and Paul M. Dolman. 

 Abstract

Hyper-herbivory following predator removal is a global issue. Across North America and Europe, increasing deer numbers are affecting biodiversity and human epidemiology, but effectiveness of deer management in heterogeneous landscapes remains poorly understood. In forest habitats in Europe, deer numbers are rarely assessed and management is mainly based on impacts. Even where managed areas achieve stable or improving impact levels, the extent to which they act as sinks or persist as sources exporting deer to the wider landscape remains unknown. We present a framework to quantify effectiveness of deer management at the landscape scale. Applied across 234 km2 of Eastern England, we assessed management of invasive Reeve’s muntjac (Muntiacus reevesi) and native roe (Capreolus capreolus), measuring deer density (using thermal imaging distance transects 780 km/year), fertility, neonatal survival, and culling to quantify source-sink dynamics over 2008–2010. Despite management that removed 23–40% of the annual population, 1,287 (95% CI: 289–2,680) muntjac and 585 (454–1,533) roe deer dispersed annually into the wider landscape, consistent with their ongoing range expansion. For roe deer, culled individuals comprised fewer young deer than predicted by a Leslie matrix model assuming a closed population, consistent with age-dependent emigration. In this landscape, for roe and muntjac, an annual cull of at least 60% and 53%, respectively, is required to offset annual production. Failure to quantify deer numbers and productivity has allowed high density populations to persist as regional sources contributing to range expansion, despite deliberative management programs, and without recognition by managers who considered numbers and impacts to be stable. Reversing an unfavorable condition of woodland biodiversity requires appropriate culls across large contiguous areas, supported by knowledge of deer numbers and fertility. 

© 2013 The Wildlife Society.

The following Press Release has been received from The Wild Deer Association of Ireland: