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Contents of Draft Document on Deer Culling, Part 1 (Background)
1.1 How many deer are there in the UK?
1.2 What is the effect of an overpopulation of deer? Do we need to keep
numbers
down?
1.3 Can deer be kept out of the areas where they can cause damage?
1.4 So if there are too many deer, can we improve woodland regeneration by
reducing their numbers?
1.5 So how are deer culled?
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1. Background
1.1 How many deer are there in the UK?
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There are more than a million deer
in mainland UK. This includes 500,000 Roe Deer, 360,000 Red Deer, 100,000
Fallow Deer and 40,000 Muntjac - from the 1995 JNCC Review of British
Mammals).
The total number of deer has risen dramatically in recent years.
Estimates were made in the early 1970s of 200,000 Roe Deer, 190,000 Red
Deer, 50,000 Fallow Deer and 5,000 Muntjac, though it is acknowledged that
these were less accurate than more recent figures.
Deer have no natural predators in the UK, save man, and uncontrolled their
population
will continue to rise.
1.2 What is the effect of an overpopulation of deer? Do we need to keep
numbers
down?
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The detrimental effects of an overpopulation of deer on our woodlands are
well documented. Any ecologist will tell you the value of preventing any
species in a woodland from getting out of control. If any of the herbivores
get too numerous, the damage done can be tremendous.
Some reference to the literature published in this field shows the necessity
of maintaining an appropriate population:
Buckley GP, Howell R, Watt TA, et al.
Vegetation succession following ride edge management in lowland plantations
and woods .1. The influence of site factors and management practices
BIOL CONSERV 82: (3) 289-304 DEC 1997
This paper gives a study of woodland regeneration.
"Deer grazing profoundly affected vegetation composition and structure,
greatly reducing tree and shrub regeneration. "
Mayle BA
Progress in predictive management of deer populations in British woodlands
FOREST ECOL MANAG 88: (1-2) 187-198 NOV 1 1996
This is a very important study on deer control. Interestingly,
there's more emphasis on the level of population control than on the
necessity for population control, the case for the necessity of control
being assumed to be beyond dispute.
Kirby KJ, Thomas RC, Dawkins HC
Monitoring of changes in tree and shrub layers in Wytham woods
(Oxfordshire), 1974-1991
FORESTRY 69: (4) 319-334 1996
Looks at a wood that has basically thinned a little in the time period,
exploring the reasons why. One of the factors was grazing by deer.
"The shrub cover has also declined greatly, probably because of increased
deer browsing."
Patel A, Rapport DJ
Assessing the impacts of deer browsing, prescribed burns, visitor use, and
trails on an oak-pine forest: Pinery Provincial Park, Ontario, Canada
NAT AREA J 20: (3) 250-260 JUL 2000
A recent study of the effect of high deer population density on
woodland.
"Higher deer densities led to significant declines in species richness, stem
density, cover, and median seedling height."
Scott D, Welch D, Thurlow M, et al.
Regeneration of Pinus sylvestris in a natural pinewood in NE Scotland
following reduction in grazing by Cervus elaphus
FOREST ECOL MANAG 130: (1-3) 199-211 MAY 1 2000
Looks at whether the initial regeneration of a gap in a forest is affected
by a number of factors. Found that the presence of red deer, grazing the
area, could give saplings a chance of germinating, but did not demonstrate
that those saplings had any increased chance of surviving to adulthood, and
the statistical increase in germination is very low.
Jorritsma ITM, van Hees AFM, Mohren GMJ
Forest development in relation to ungulate grazing: a modelling approach
FOREST ECOL MANAG 120: (1-3) 23-34 JUL 12 1999
"The results presented in this paper concern the development of a pine
forest (Pinus sylvestris L.) in the Netherlands under various grazing
pressures over a period of 100 years. They show that even low densities of
ungulates can have significant impacts on the regeneration and thereby on
forest development. "
Radeloff VC, Pidgeon AM, Hostert P
Habitat and population modelling of roe deer using an interactive geographic
information system
ECOL MODEL 114: (2-3) 287-304 JAN 1 1999
Discusses the level to which culling is necessary.
"We describe a model to determine deer population densities compatible with
forest management goals, and to assess harvest rates necessary to maintain
desired deer densities. "
Impact of bark stripping by sika deer, Cervus nippon, on subalpine
coniferous forests in central Japan
Yokoyama N, Maeji I, Ueda T, Ando M, Shibata E
FOREST ECOLOGY AND MANAGEMENT
140: (2-3) 93-99 JAN 15 2001
Demonstrates that a major killer of trees was sika deer. By stripping too
much bark, trees died, which led to a long term change in the species of
plants represented in those forests and an overall loss of woodlands.
Online information sources also comment on the effects of having more large
herbivores than can be sustained in a habitat. The Scottish Wildlife Trust
for example have published a statement on the necessity of their culling
policy.
(http://www.swt.org.uk/Publications/Policies/reddeerpol.htm)
"Red deer may also cause serious damage to blanket bogs, by wallowing in
pools and in association with grazing sheep, are responsible for many
arctic-alpine plants (e.g.: Alpine Sow Thistle) being restricted to
inaccessible rocky outcrops and ledges. Scotland's Red Deer population is
forever increasing (from around 216,000 in the early 1960s to over 300,000
in 1986), so it is likely that the environmental problems associated with
them will also continue to increase in size. A solution must be found soon."
In the year 2000, 71 000 deer were culled in Scotland. Despite this, the
population continues to rise
(http://213.235.21.10/LifeCountry/Pursuits/shoot_news6.htm). Although many
animal rights activists undoubtedly find the culling of deer to maintain
sustainable population density quite distasteful, organisations such as the
League Against Cruel Sports (http://www.league.uk.com/) accept the necessity
of this practice.
The largest, and most famous population of deer in England is within the
Exmoor National Park. With the possible demise of hunting of deer with
hounds in that area, the Burns enquiry concluded that the development of an
alternative culling strategy to maintain numbers at a sustainable level is
of critical importance (quoted at:
http://www.parliament.the-stationery-office.co.uk/pa/cm199900/cmhansrd/vo000
707/debtext/00707-05.htm)
1.3 Can deer be kept out of the areas where they can cause damage?
-----------------------
In some instances, fences can be used to keep deer out. This is especially
useful when new saplings have been planted. Unfortunately, this doesn't
provide a complete answer.
The choice of how to protect your saplings comes down to either individual
tree protection or fencing of a whole area. Fencing can be problematic,
especially in Scotland, for a number of reasons.
One of the emblems of the Scottish countryside is the capercaillie. This
bird is unfortunately endangered, its numbers severely restricted having
halved in the last ten years to no more than 1000 individuals. One of
the reasons for this is the use of deer fencing within and around areas of
woodland. The birds, adults and young, fly low between the trees, hit the
fences and die. This has been demonstrated in the
following research papers:
Capercaillie Tetrao urogallus in Scotland - demography of a declining
population
Moss_R, Picozzi_N, Summers_RW, Baines_D
IBIS, 2000, Vol.142, No.2, pp.259-267
And
Assessment of bird collisions with deer fences in Scottish forests
Baines_D, Summers_RW
JOURNAL OF APPLIED ECOLOGY, 1997, Vol.34, No.4, pp.941-948
Quotes from this report: "This study adds weight to previous
findings that fences are a frequent cause of mortality in capercaillie", and
"a policy of deer culling to achieve tree regeneration without deer fencing
would be desirable wherever practicable and especially within the range and
main native pinewood habitat of capercaillie".
One RSPB document (http://www.ierm.ed.ac.uk/restore/proc8.htm) states :
"We now know that the effect of deer fences on woodland grouse has been very
severe. Fences are probably one of the main reason why capercaillie have
declined from around 20,000 birds in the 1970's to about 2,200 birds at the
present time. At Abernethy, as a result of fence removal and improvements in
habitat, there has been a 300% increase in the number of lekking males"
Quoting again from the Scottish Wildlife Trust
(http://www.swt.org.uk/Publications/Policies/reddeerpol.htm)
"While deer fencing can exclude deer from specific areas, and can be used to
promote (for example), woodland regeneration it has many drawbacks. It is
expensive to erect, concentrates grazing deer at a higher density in areas
beyond the fence, it can cause fatalities amongst birds such as capercaillie
(when they fly into fences), and unless it is very well planned it can cause
access problems in areas used for outdoor recreation."
The above article continues with a discussion of the problems with deer
climbing over
the fences in snowy conditions and becoming trapped.
The alternative to this is individual tree protection. While this can be
done to protect saplings in new plantations, it is extraordinarily
expensive. A quote from a private contractor, with the comparative cost of
protected and unprotected planting, is shown below
Comparative typical planting costs of 40 - 60 cm. native tree saplings.
All figures at per 1000 rate. Costs may vary according to scale, conditions,
stocking density and management company. Bare planting:
Tree - 40 - 60 cm. 15p
+VAT + delivery
Labour 9p
Profit @ 20% 5p +VAT
29p
Optimum planting density 2250 per ha. @ 29p = £652:50 per ha.
Planting in standard 1.2 m 'tubes' (effective against roe deer)
Tree - 40 - 60 cm. 15p
+VAT + delivery
Standard tube 67p +VAT +
delivery
4'6" planting stake 31p
+VAT + delivery
Labour 45p +VAT
Removal of tube and stake at 5-8 years 11p +VAT
Transport and disposal of tubes. 3p +VAT
Profit @ 20% 34p +VAT
£2:06p
2250 per ha @ £2:06p = £4,635 per ha
Plus environmental costs of tube production and landfill.
Labour costs for replacing any failed trees in years 1 and 2 are also much
higher than for bare planted trees because each tube has to be checked
individually, removed and re-attached during replacement planting.
Thus, planting trees with individual protection is more than seven times
more expensive. While
preventing the deer from eating the saplings, this technique does nothing to
reduce deer numbers. The result can be an overgrazed forest floor, with
little species diversity, and a lack of any natural regeneration of trees.
1.4 So if there are too many deer, can we improve woodland regeneration by
reducing their numbers?
--------------------------------------
Deer do not have to be completely eliminated to allow woodlands to
regenerate. In the RSPB reserve at Abernathy
(http://www.ierm.ed.ac.uk/restore/proc8.htm) a reduction of deer numbers
from 12 per hectare to less than four had a radical effect on woodland
regeneration.
"In one area of Abernethy, a scatter of pine trees were left after a big
felling during the 1st World War. On this site there has been no
regeneration for the last 100 years. As a result of our deer management,
around some of these old trees there are little pockets of regeneration
starting to appear."
The recover of important shrub communities, with species such as dwarf birch
and juniper, has also been recorded at this site.
But it's not just the plant community that prospers when deer numbers are
reduced to a sustainable level. As mentioned above, at Abernathy the
numbers of important bird species have increased massively as a result of
maintaining a sustainable number of deer.
Further information on this project can be found in this reference:
Beaumont, D., Dugan, D., Evans, G. and Taylor, S. (1995): Deer management
and tree regeneration in the RSPB reserve at Abernethy Forest. Scottish
Forestry, 49(3), 155-161
1.5 So how are deer culled?
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The Association of Deer Management Groups has strict guidelines for how this
is achieved (http://www.deer-management.co.uk/).
"This is undertaken by professional stalkers who have unmatched experience
in working with wildlife in Scotland, and a close knowledge of deer in
particular. The culling of deer involves the selection of older or unhealthy
animals which are shot humanely with a high velocity rifle. Culling policy
is agreed by Deer Management Groups and allocated among their members on the
basis of a regular coordinated count by the Group, or by the Deer Commission
for Scotland"
The welfare implications of killing red deer by this method were explored in
depth in this work.
Welfare implications of culling red deer (Cervus elaphus)
Bradshaw EL, Bateson P
ANIMAL WELFARE
9: (1) 3-24 FEB 2000
This study found that almost 90% of deer were killed with a single shot, and
that only 7 percent took between 2 and 15 minutes to die. Only about 2% of
animals escaped wounded. Despite this high success rate, the study concluded
that there is still scope to improve on this.
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