Data from: Fear of the dark? contrasting impacts of humans vs lynx on diel activity of roe deer across Europe

Humans, as super predators, can have strong effects on wildlife behaviour,
including profound modifications of diel activity patterns. Subsequent to
the return of large carnivores to human-modified ecosystems, many prey
species have adjusted their spatial behaviour to the contrasting
landscapes of fear generated by both their natural predators and
anthropogenic pressures. The effects of predation risk on temporal shifts
in diel activity of prey, however, remain largely unexplored in
human-dominated landscapes. We investigated the influence of the density
of lynx (Lynx lynx), a nocturnal predator, on the diel activity patterns
of their main prey, the roe deer (Capreolus capreolus), across a gradient
of human disturbance and hunting at the European scale. Based on 11
million activity records from 431 individually GPS-monitored roe deer in
12 populations within the EURODEER network (http://eurodeer.org), we
investigated how lynx predation risk in combination with both lethal and
non-lethal human activities affected deer diurnality.  We
demonstrated marked plasticity in roe deer diel activity patterns in
response to spatio-temporal variations in risk, mostly due to human
activities. In particular, roe deer decreased their level of diurnality by
a factor of 1.37 when the background level of general human disturbance
was high. Hunting exacerbated this effect, as during the hunting season
deer switched most of their activity to nighttime and, to a lesser extent,
to dawn, although this pattern varied noticeably in relation to lynx
density. Indeed, in the presence of lynx, their main natural predator, roe
deer were relatively more diurnal. Overall, our results revealed a strong
influence of human activities and the presence of lynx on diel shifts in
roe deer activity. In the context of the recovery of large carnivores
across Europe, we provide important insights about the effects of
predators on the behavioural responses of their prey in human-dominated
ecosystems. Modifications in the temporal partitioning of ungulate
activity as a response to human activities may facilitate human-wildlife
coexistence, but likely also have knock-on effects for predator-prey
interactions, with cascading effects on ecosystem functioning.