Eat or be eaten: Implications of potential exploitative competition between wolves and humans across predator- savvy and -naive deer populations

Recolonization of predators to their former ranges is becoming
increasingly prevalent. Such recolonization places predators amongst their
prey once again; the latter having lived without predation (from such
predators) for considerable time. This renewed coexistence creates
opportunities to explore predation ecology at both fundamental and applied
levels. We used a paired experimental design to investigate white-tailed
deer risk allocation in the Upper and Lower Peninsulas (UP and LP) in
Michigan, USA. Wolves are functionally absent in the LP, while deer in the
UP coexist with a re-established wolf population. We treated 15 sites each
in UP and LP with wolf olfactory cues and observed deer vigilance,
activity, and visitation rates at the interface of habitat covariates
using remote cameras. Such a paired design across wolf versus no-wolf
areas allowed us to examine indirect predation effects while accounting
for confounding parameters such as the presence of other predators and
human activity. While wolf urine had no effect across most metrics in both
UP and LP, we observed differences in deer activity in areas with versus
without wolves. Sites treated with wolf urine in the UP showed a reduction
in crepuscular deer activity, compared to control/novel-scent treated
sites. Further, we observed a strong positive effect of vegetation cover
on deer vigilance in these sites. This indicates that simulated predator
cues likely affect deer vigilance more acutely in denser habitats, which
presumably facilitates predation success. Such responses were however
absent among deer in the LP that are presumably naïve towards wolf
predation. Where human and non-human predators hunt shared prey, such as
in Michigan, predators may constrain human hunting success by increasing
deer vigilance. Hunters may avoid such exploitative competition by
choosing hunting/bait sites located in open areas. Our results pertaining
to fundamental predation ecology have strong applied implications that can
promote human-predator coexistence.