Large carnivores influence ecosystem dynamics in multiple ways, for example, by
suppressing meso-carnivores
and providing carrions for smaller scavengers. Loss
of large carnivores is suggested to cause meso-carnivore
increase and expansion.
Moreover, competition between meso-carnivores
may be modified by the presence
of larger carnivores. In tundra ecosystems, the smallest meso-carnivore,
the
Arctic fox, has experienced regional declines, whereas its larger and competitively
superior congener, the red fox, has increased, potentially due to changes in
the abundance of apex predators.
2. We explored if variation in the occurrence of wolverine and golden eagle impacted
the occurrence and co-occurrence
of the Arctic fox and red fox in relation
to varying abundances of small rodents within the Scandinavian tundra.
3. We applied multi-species
occupancy models to an extensive wildlife camera
dataset from 2011–2020
covering 98 sites. Daily detection/non-detection
of
each species per camera trap site and study period (late winter; March–May)
was
stacked across years, and species occupancy was related to small rodent abundance
while accounting for time of the year and status of simulated carcass.
4. The Arctic fox was more likely to co-occur
with the red fox when the wolverine
was present and less likely to co-occur
with the red fox when golden eagles were
present and the wolverine was absent. Red foxes increased in occupancy when
co-occurring
with the larger predators. The Arctic fox responded more strongly
to small rodent abundance than the red fox and co-occurred
more often with the
other species at carcasses when rodent abundance was low.
5. Our findings suggest that the interspecific interactions within this tundra predator
guild appear to be surprisingly intricate, driven by facets of fear of predation,
interspecific mediation and facilitation, and food resource dynamics. These
dynamics of intraguild interactions may dictate where and when conservation
actions targeted towards the Arctic fox should be implemented.
carnivores, competition, co-occurrence,
intraguild interaction, occupancy, predation, resource
availability, tundra
