Human avoidance, selection for darkness and prey activity explain wolf
diel activity in a highly cultivated landscape in West-Central Europe
Abstract
Wolves and other wildlife species that share habitats with humans with
minor options for spatial avoidance must either tolerate frequent human
encounters, which may be lethal, or allocate their activity to those
periods of the day when the risk of encountering humans is smallest and
the consequences least severe. This may force wolves in densely
human-populated and cultivated landscapes to either become highly
nocturnally active or habituate to human stimuli. Based on 6,220 camera
trap images of adult wolves from eight territories in Denmark, we
analyzed the extent to which diel activity patterns in a wolf population
in a highly cultivated landscape with fragmented forests and extensive
public access could be explained from diel variation in darkness, human
activity, and prey (deer) activity. We found that diel activity
correlated with all three factors simultaneously with human activity
(negative) having the strongest total as well as partial effect,
followed by darkness (positive) and deer activity (positive). Relative
to a model that smoothed activity as a function of time of the day, the
three factors accounted for 94% of the explainable diel variation in
wolf activity. As most of the apparent selection for darkness could be
explained by temporal human avoidance, we suggest that nocturnality
(proportion of observations registered at night vs. day at equinox) is a
useful proxy for investment in temporal human avoidance. In this study,
wolf packs were 7.0 (95% CI: 5.0-9.7) times more active at night than
at daytime, which makes Danish wolves amongst the most nocturnally
active wolves reported so far. This result confirms the initial
prediction that wolves with few options for spatial avoidance, invest
heavily in temporal human avoidance.