European badger (Meles meles) responses to low-intensity, selective culling: using mark recapture and relatedness data to assess social perturbation

Culling the main wildlife host of bovine tuberculosis in Great Britain
(GB) and Ireland, the European badger (Meles meles) to reduce infections
in cattle, has been employed in both territories. In GB, this has been
controversial, with results suggesting that culling induces disturbance to
badger social structure, facilitating wider disease dissemination.
Previous analyses hypothesized that even very low-level, selective culling
may cause similar deleterious effects by increasing ranging of individuals
and greater mixing between social-groups. To assess this hypothesis, a
novel, prospective, landscape-scale ‘before-and-after’ Test and vaccinate
or remove (TVR) study was implemented. Test-positive badgers were culled
and test-negative badgers were BCG vaccinated and released. Mark-recapture
metrics of badger ranging and genetic metrics of social group relatedness
did not change significantly over the study period. However, selective
culling was associated with a localised reduction in social-group
relatedness in culled groups. Synthesis and application: Ecological
context is important; extrapolation across territories and other disease
epidemiological-systems (epi-systems) is likely to be challenging.
However, we demonstrate that small-scale, selective removal of
test-positive badgers was not associated with metrics of increased ranging
but was associated with localised changes in social-group relatedness.
This adds to the evidence base on badger control options for policy
makers.