A study led by scientists at the Agri-Food and Biosciences Institute (AFBI), in conjunction with DAERA, has concluded that there is no compelling evidence that badger social groups are disturbed by selective culling.
The work, published in the journal Ecological Solutions and Evidence, looked at whether culling in a zone will lead to remaining badgers roaming further and potentially joining other social groups. This so-called perturbation effect was highlighted in a large field study done in England, which started in the late 1990s.
The English researchers concluded that widespread culling could not contribute effectively to TB control as those badgers left behind in cull areas tended to range more widely, spreading infection to non-cull areas. In the 2km area around cull zones, a 25% increase in cattle TB was recorded.
That work led an expert group in NI (the TB Strategic Partnership Group - TBSPG) to recommend to DAERA that as part of a future badger cull, a 1.5km buffer zone be set up around cull areas. Within this buffer, badgers should be tested for TB, with infected animals removed, and healthy animals vaccinated for the disease.
However, while much of what the TBSPG recommended forms the basis for a new TB eradication strategy published by DAERA in March 2022, there are no plans to vaccinate badgers in areas surrounding a control zone. The basis for that relies on work from the Republic of Ireland which shows no perturbation occurs in badgers when animals are culled, and also the AFBI research paper just published.
It considered results from the Test, Vaccinate or Remove (TVR) badger study undertaken across a 100km2 part of Co Down between 2014 and 2018.
In total, 108 badgers were removed as test positive out of 827 unique capture events, with 77 different badger social groups identified across 94 setts. Of these, 56 groups saw selective culling. Out of 391 badgers captured in more than one year, only four animals had changed social groups.
“Our results show no compelling evidence of a generalised social perturbation effect in badgers at the population level under this selective culling protocol,” states the AFBI paper.