Farming interests and badger protectionists have battled for 30 years over the merits of culling badgers to fight cattle tuberculosis, which in the past was transmitted through unpasteurized milk to people. The new reports summarize seven years of study for the British Department for Environment, Food and Rural Affairs (Defra), which is expected to make statements on the findings tomorrow (Dec. 15) in Parliament and elsewhere in government.
"In Britain, this is a huge controversy because TB genuinely affects farmers' livelihoods, but badgers are beloved by the public and protected by law," said Woodroffe, an associate professor of conservation biology and an authority on the biology of the European badger (Meles meles). "Imagine our American bison/brucellosis issue and our wolf/livestock predation issue rolled into one." (North American badgers,Taxidea taxus, do not carry bovine tuberculosis.)
The reports by Woodroffe and her colleagues from the Independent Scientific Group on Cattle TB and Central Science Laboratory were published online today in the British journal Nature and the British Ecological Society's Journal of Applied Ecology.
They observed that whether culling was widespread or localized, it disrupted the badgers' territorial organization and made them travel more widely.
Where culling was widespread, badgers were so few that even with larger ranges, their cattle encounters declined, and so did cattle TB infection, which fell by 19 percent.
However, where culling was restricted to localized areas, and on farms neighboring extensive culling areas, badger numbers fell only slightly and cattle TB incidence rose by 25 to 29 percent. Woodroffe said that was probably because the relatively stable badger numbers, combined with increased ranging, meant cattle herds encountered more badgers than they might if none had been killed at all.
The researchers concluded that on the geographic scales tested (up to 100 square kilometers, or 37 square miles), the negative effects of culling greatly outweighed the benefits.
Woodroffe said the findings underscored the importance of ecological research in sound policy making - particularly as localized badger culling was government policy for more than 20 years.
UC Davis, the University of California's flagship campus for environmental studies, has a strong and growing expertise in understanding relationships among wildlife, livestock and people around the world.