Introduction
Grey wolf (Canis lupus) |
Eurasian lynx (Lynx lynx) |
International treaties, such as the Bern Convention (1979) and the Rio Convention (1992), oblige the UK to encourage the restoration
of populations of native species, while the EC Habitats Directive (1992) obliges
the UK to consider the desirability of
reintroducing former British natives such as the wolf, lynx and bear.
European brown bear (Ursus arctos) |
Large carnivores (top predators) are capable (depending on the circumstances) of controlling not only the distribution but also the abundance of
their prey. This can enhance the overall biodiversity and ecological
integrity (native components are intact) of the environment.
The Grey Wolf
Scientific knowledge of the role of the wolf in ecosystems has increased
greatly. In some areas there has been a marked
change in public attitudes towards the wolf and this change in attitudes has
influenced governments to revise and even eliminate archaic laws. In Europe, wolves are still killed even when
compensation is paid and when economic
incentives are provided for better damage
prevention.
Distribution of wolves in Europe |
History in Britain. The Wolf
The wolf was the last of the large carnivores to become extinct in Britain,
disappearing in the 17th century. Hunting by humans was the primary cause;
either due to the perceived threat to livestock or for sport. Wolves have also been
hunted and trapped in countries such as Alaska and Canada for their fur. The
wolf now ranges across parts of the United States, including Alaska, Idaho, Michigan,
Minnesota, Montana, Wisconsin and Wyoming as well as Canada, Russia and a few eastern
European countries.
Although extinct in Britain, the wolf is
recovering naturally in Europe, where it is believed its population may have
reached numbers of up to 18,000. It was once present on every continent of the
Northern hemisphere, where it played a critical role in maintaining the ecosystems
to which it belongs.
Wolves were part of the natural wild
fauna of Britain from inter-glacial times, approximately 50,000 years ago. As
the glaciers of the last Ice Age retreated, about 10,000-12,000 years ago,
wolves again re-colonised the British Isles. Mesolithic population estimates
for the wolf stand at 7,000 individuals. The wolf was common throughout Britain
in Saxon times where it thrived during wars. It disappeared from southern Britain about 800 years ago, although
it was locally common at the time of the Battle of Hastings, where it scavenged
the dead. A fossilised wolf jaw was discovered in Kent which was dated to
1300AD, a time in which the wolf was supposedly extinct from the area. The last British wolf is reputed to have been
killed in Scotland in 1743, but the species disappeared from England by 1680.
People’s negative view of wolves is often due to myths and superstitions
that have been passed down through generations.
Very few validated encounters of wolves attacking humans have ever been
documented. When humans were hunter-gatherers the wolf was seen as a
resourceful, powerful fellow-hunter. When we began tending livestock, the wolf remained
a hunter, but then became a competitor. This is when the demise of the wolf began.
Ecology and Behaviour
Wolf ecology
The grey wolf was once the most widely distributed of all land
mammals. Although only found in northern latitudes, wolves can live in a variety
of habitats, as long as prey density is high enough to sustain a viable
population. Wolves are opportunistic
predators, feeding primarily on large ungulates such as deer, elk and wild boar.
[…]
[…] The wolf is the largest member of
the dog family, with the ability to hunt and kill animals of a larger size than
itself. The wolf’s physical traits and adaptations
reflect its predatory instincts. […]
[…] Wolves have amazing hearing and can detect other wolves howling from 6
miles away in forests and 10 miles away across open countryside. Wolves may
howl to call the pack together, as a ritual or to find and identify each other
and outsiders. […]
Wolf Social Structure and Organisation […]
Ecological Niche
Ecological niche is defined as the place or function of a given organism
within its ecosystem. Different organisms may compete for the same niche. The wolf’s niche is as a predator of the
northern hemisphere that preys upon large mammals. Found within the same ecological
niche as wolves are the felids such as the lynx, mountain lions in North
America and tigers and leopards in Asia. Humans
would also be found within this ecological niche.
Reintroductions
Wolf. Impacts on large herbivores
There are numerous arguments for and
against the reintroduction of large carnivores such as the wolf back into
Britain. Attitudes to reintroductions of carnivores tend to be favourable among
the general public, but negative amongst those seen to be adversely affected.
There have been no reintroductions of large carnivores in Britain to date. […]
[…] There is a large discrepancy between
support from individuals that live within the proposed reintroduction site and
those that live elsewhere. It is inevitable that if wolves are released into the wild, farmers at some point will lose a
proportion of their livestock to wolves. […]There has been much discussion
on reintroducing the grey wolf to the Scottish
highlands, where it survived the longest in Britain. The main advantage
would be the control of red deer (Cervus
elaphus) and roe deer (Capreolus
capreolus) populations. Humans kill
75,000 red and roe deer annually in Britain, whereas wolves only kill
around 20 deer a year each. […] At present deer numbers are controlled by annual
culling by humans. It is impossible to allow
deer populations to grow exponentially without serious implications for natural
habitats. There is not enough
woodland in Britain to support ever increasing deer populations.
Ciervo rojo
(Cervus, canadensis), en Rannoch Moor, Escocia.
Foto de A.
Thompson, 2008. Fuente.
|
If wolves were reintroduced, farmers
would not have to pay people to come onto their land to cull deer which are
damaging it. Human trophy hunting involves taking the fittest specimens from a
deer population. Wolves do not take individuals in this manner. Instead their instinct is to weed out the old,
lame, young and sick individuals leading to smaller, fitter deer populations.
La Isla de Rhum. Fuente. |
Attacks on humans and livestock
Wolf attacks on humans are extremely rare;
the majority of attacks occur in rabid
individuals. Although wolves do not act as reservoirs for rabies, they can
catch it from other species. […] Linnell
et al identified four factors that are associated with wolf attacks on humans; rabies,
habituation (wolves that had lost their fear of humans), provocation and highly
modified environments. […]
Ganadería en las Highlands escocesas. Fuente |
At present in Britain there is no state compensation for damage caused
by wildlife and it is likely that any such scheme
would have to be funded by the voluntary sector. The damage to livestock has the potential to be high, due to the free
ranging unsupervised stock which is found throughout the Scottish Highlands,
coupled with wolf dispersal distances of up to several hundred kilometres. Wolves
will take domestic livestock if wild prey is scarce, primarily sheep and goats.
Although wolf predation on livestock within specific regions is low, impacts on
individual farmers can be high. A return
to more traditional livestock management practices, for example attending
herds and guarding at night, could be considered to avoid sheep losses.
Case Study: Yellowstone National Park,
USA […]
Natural Selection and Survival of the
Fittest
Natural selection is the theory which states that those individuals best
adapted to their environment tend to survive and produce offspring, passing on
their genes to successive generations. Large predators tend to prey on sick,
injured, diseased and old animals over healthy individuals. These animals
would be expected to be less effective reproducers and they may also slow down
the herd. Hence they are not as well adapted to their environment.
Genetic drift is the natural consequence of sexual
reproduction and the random mixing of genes which this involves. A small population has a greater chance of
completely losing a gene. Inbreeding depression can also be a problem,
reducing the overall genetic variability, and introducing harmful and
potentially lethal genes into the population.
Predators such as wolves can aid in removing congenital abnormalities or
proneness to disease from the population,
preventing these traits from being passed down through successive generations
(survival of the fittest). […]
[…] Humans
tend towards trophy hunting and therefore do not choose individuals to hunt in the
same way as would a wolf. Unless professional deer stalking for herd management
is undertaken, natural selection does not occur in the same way as it would were
the deer being hunted by predators such as wolves. […]
Las montañas de Cuillin en las Highlands escocesas ofrecen un
entorno virgen para la reintroducción del lobo. |
The outcome of reintroductions tends to be very different for captive
bred carnivores, compared to wild caught ones.
This is due to the numerous limitations of reintroducing animals who have never
had to fend for themselves. In the wild, parents would teach their offspring
how to hunt their own food as well as how to build dens, select a suitable mate,
avoid humans and compete with other top predators occupying the same ecological
niche. They would learn that if food reserves are low in a particular area,
they must move to a new area in order to survive. If captive bred carnivores were to be reintroduced to the Scottish
highlands lacking these required skills, they would find it difficult to
survive for prolonged periods of time.
[…] If
reintroductions were to occur, it would be more successful if young, dispersing
animals were caught and translocated from other regions in Eurasia where their
numbers are sustainably high. The large home ranges and low population
densities of large carnivores mean that the
Scottish Highlands is the only UK region with the potential to support a viable
population. […]
Evolution
Evolutionary theory predicts that in the absence of predators, prey
species will lose their defensive behaviour. This is especially prevalent in island
populations. Deer and other prey
species of wolves, lynx and brown bears have evolved over the past 300 years in
Britain without the presence of a top predator. Have humans suitably filled
this niche, preventing such animals from becoming accustomed to a predator free
environment? How will deer fare with the reintroduction of wolves and the lynx
in terms of their behaviour? Will it have any affect on their breeding success?
Will translocated wolves from abroad adapt to a sudden change in prey species? Reintroduction of large carnivores comes
with numerous questions and issues that must be addressed prior to release.
Conclusions
Paul Lister logró reintroducir el alce en la reserva natural de Escocia. |
The biggest foreign landowner in
Scotland, the late Paul van Vlissingen,
also wanted to reintroduce wolves and lynx to the Scottish countryside. A three
year study of his 80,000 acre Letterewe estate showed that traditional culling was having little impact on deer numbers.
These results demonstrated that deer were not being properly managed and that reintroduction of large carnivores
would be a more effective method of control. Both Paul Lister and Paul van
Vlissingen believe that wolves and lynx would provide a basis for ecotourism in the region.
El nicho ecológico del lobo y el paisaje. Fuente: Howling for Justice |
Reintroducing Large
Carnivores to Britain: Grey Wolf, Eurasian Lynx and European Brown Bear. Wildwood (2006) http://bit.ly/Oq0TPN (Publicado
en internet por http://www.wildwoodtrust.org )
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