Determinants of co-occupancy
In both winter and autumn, co-occupancy for lynx and wolf was relatively
high indicating that both species have similar habitat requirements. In
winter there was a weak effect of forest cover on the co-occupancy of
lynx and wolf; co-occupancy increased slightly with proportion of forest
cover >0.75. Increased forest cover may result in an
increase in prey availability, which would yield higher co-occupancy
between lynx and wolf which share some prey items (primarily roe deer,
red deer calves), and the main prey species for wolf, the wild boar
(Sus scrofa ) (Sin et al., 2019) shares similar habitat with red
and roe deer. In autumn, terrain ruggedness was a negative predictor of
co-occupancy for lynx and wolf, such that predicted co-occupancy was
~0 for the highest values of terrain ruggedness. This
relationship is driven by the negative relationship between marginal
occupancy for wolf and terrain ruggedness, which is also related to prey
availability (see above) (Figure 2C). Because marginal occupancy for
wolf is ~0 at high terrain ruggedness, co-occupancy for
lynx and wolf is low as well. Additionally, co-occupancy between wolf
and wildcat decreased with terrain ruggedness in autumn (Fig 3F) due to
the low marginal occupancy for wolf at high terrain ruggedness. In
winter however, co-occupancy of wolf and wildcat was predicted by
proportion of forest such that increasing forest cover resulted in lower
co-occupancy (Fig 3C). In both seasons, the co-occupancy of lynx and
wildcat increased with terrain ruggedness, but the relationship was
stronger in winter (Fig 3A, D). This relationship also provides further
evidence that the negative relationship observed for lynx and wolf
co-occupancy and terrain ruggedness was driven by wolf marginal
occupancy.