Impact of wildlife culling on the physiological stress and space use of a social herbivore

Wildlife culling is a widely used but often contentious management tool
for controlling overabundant species. While previous research suggests
that behavioural responses of eastern grey kangaroos (Macropus giganteus)
to culling are relatively minor, physiological measures can offer
additional insight into how animals perceive such events. In this study,
we assessed changes in faecal glucocorticoid metabolite (FGM)
concentrations to evaluate the physiological response of kangaroos to a
conservation cull in the Australian Capital Territory. We collected faecal
samples immediately before (n = 255) and after (n = 171) the cull and
analysed FGM levels alongside patterns of space use inferred from
GPS-located faeces. Post-cull FGM concentrations were 29% lower than
pre-cull levels, suggesting a subdued physiological response inconsistent
with what might be expected following a major predation-like event.
Additionally, kangaroos were found to graze further from refuge sites
after the cull, further indicating reduced stress or increased perceived
safety. Our findings align with previous behavioural data and suggest that
the culling operation had minimal negative impact on the remaining
individuals. This study highlights the value of incorporating
physiological metrics into wildlife assessments and demonstrates the
importance of multi-faceted approaches in evaluating the outcomes of
wildlife management interventions.