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A new study has found that roadworks are unlikely to cause major disruption to badgers’ habitats or contribute to the spread of TB.
Badgers can act as a wildlife reservoir for TB and historically, roadworks have been blamed for disrupting badgers and forcing them to travel to new territories, therefore spreading TB across farmland.
However, Dr Aoibheann Gaughran’s PhD thesis for Trinity College Dublin, entitled The impact of roadworks on the ranging behaviour of European badgers, sheds new light on badger behaviour that tackles this idea.
The concern for farmers is that when badgers move there could be an increase in disease transmission. What we found was that during roadworks they only moved on average an extra 80m
“We put trackers on 80 badgers and followed their movements along 16km of N11 that was being upgraded in Co Wicklow. Over seven years, we tracked 139 individuals,” Gaughran said.
“Badgers live in social, family groups, generally with two dominant badgers and their offspring. Their home range is defined within a territory.”
In Ireland, badger families have an average home range of 1.4km².
Gaughran’s research showed that although badgers were highly active within their own territory, the degree to which they ventured outside their territory boundaries during roadwork activity did not increase.
“The concern for farmers is that when badgers move there could be an increase in disease transmission. What we found was that during roadworks they only moved on average an extra 80m,” Gaughran said.
Her research also highlighted that on average 22% of male badgers are defined as “super-rangers” that had larger than average home ranges, presumably for better mating and foraging opportunities, but the roadworks had no impact on these individuals.
However, even these badgers are also territorial and usually only exist in a well-defined territories.
Gaughran pointed out that the death of a badger through a road fatality, culling or persecution could cause problems for farmers.
“When a badger dies, on a road for example, a vacuum is created in their social group, which may be healthy and TB-free. This vacuum prompts another badger to come in from a different, and possibly infected, area,” she said.
While the N11 roadworks did not seem to disrupt badger activity, Gaughran acknowledges that a huge amount of work had been carried out in creating badger-proof fencing to prevent deaths on the new motorway and building underpasses to allow badgers to continue ranging normally.
This mitigation acted to prevent further disruption to badgers after the roadworks themselves had ended and once the new motorway had opened.
She urged other local authorities to carry out similar measures when undertaking roadworks.
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