Badger culls 'boost fox numbers'
19 December 2007 - BBC News
Culling badgers in order to control bovine tuberculosis (bTB) can cause a
doubling in fox numbers, UK government scientists have found. This could impact
on livestock farming and conservation, the authors write in Biology Letters
The researchers looked at effects on foxes during the badger culling trials
in England between 1998 and 2006. Their figures show that intensive culling of
badgers resulted in roughly one extra fox per square kilometre. Red foxes are of
concern to farmers and conservationists alike because they prey on livestock,
ground-nesting birds and brown hares. They are widely culled by farmers and
The Randomised Badger Culling Trial (RBCT) was set up to investigate how bTB
spread between cattle, badgers and other wildlife. It also enabled scientists to
assess the effects of badger culls on other species sharing the same ecosystem.
It was understood that red foxes might be affected because the foxes use badger
setts as breeding dens and share a similar diet - suggesting the two species may
compete for food.
"What we saw was an increase of fox numbers in the culled areas," Mr Trewby,
from the Central Science Laboratory, told BBC News. Mr Trewby said: "Obviously
it is a contentious issue whether foxes have a significant impact on farming.
They may have an impact, or there may be increased mortality, but that's
something we can't comment on at the moment."
Rosie Woodroffe, senior research fellow at the Zoological Society of London,
commented: "I think it is another aspect of badger culling that needs to be
taken into account in deciding on the modest benefits of culling badgers set
against a number of costs."
Dr Woodroffe, who is a member of the ISG, said: "What we concluded was that
the only way you could have even a modest benefit for control of cattle TB was
by culling badgers on an extremely large geographic scale, over long periods of
time in a highly co-ordinated way. She added: "If you don't do it in that way,
you actually make it worse. Badgers are social and highly territorial. This
limits the spread of disease because infected badgers are mainly going to
interact with their own group. When you cull the badgers, you break down that
territoriality, so the badgers are ranging more widely and meeting more herds of
cattle. But they are also more likely to be interacting with what used to be
neighbouring social groups."
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