Predicting multi-predator risk to elk (Cervus canadensis)
using scats: Are migrant elk exposed to different predation risk?
KARA M. MacAULAY ̵̶ Department of Biological Sciences, University of
Alberta, Edmonton, Alberta T6G 2E9, CANADAhttps://orcid.org/0000-0003-1001-6906
ERIC G. SPILKER ̵̶ Department of Biological Sciences, University of
Alberta, Edmonton, Alberta T6G 2E9, CANADA
JODI E. BERG ̵̶ Department of Biological Sciences, University of
Alberta, Edmonton, Alberta T6G 2E9, CANADA https://orcid.org/
0000-0003-0678-8137
MARK HEBBLEWHITE ̵̶ Wildlife Biology Program, Department of
Ecosystem and Conservation Sciences, W. A. Franke College of Forestry
and Conservation, University of Montana, Missoula, Montana 59812, USAhttps://orcid.org/0000-0001-5382-1361
EVELYN H. MERRILL ̵̶ Department of Biological Sciences, University
of Alberta, Edmonton, Alberta T6G 2E9, CANADAhttps://orcid.org/0000-0001-7737-958X
- ABSTRACT: There is growing evidence that prey can perceive
the risk of predation and alter their behaviour in response, resulting
in changes in spatial distribution and potential fitness consequences.
Previous approaches to mapping predation risk across a landscape
quantify predator space use to estimate potential predator-prey
encounters, yet this approach does not account for successful predator
attack resulting in prey mortality. An exception is a prey kill site,
which reflects an encounter resulting in mortality, but obtaining
these data can be expensive and requires time to accumulate adequate
sample sizes.
- We illustrate an alternative approach using predator scat locations
and their contents to quantify spatial predation risk for elk(Cervus canadensis ) from multiple predators in Alberta, Canada.
We combined spatial predictions of scat-based resource selection
functions (RSFs) for bears (Ursus arctos/U. americanus ),
cougars (Puma concolor ), coyotes (Canis latrans ), and
wolves (C. lupus ) based on surveys with scat-detection dogs
with predictions for the probability that a predator-specific scat in
a location contained elk. We evaluated our approach by comparing
predictions to a model of predation risk developed from elk kill sites
and applied it to describing spatial patterns in predation risk that
were consistent with changes in the distribution of elk over the past
decade.
- We found a strong correlation between risk predicted by kill sites and
risk predicted by our approach (r = 0.98, P <
0.001). There was a spatial pattern to predation risk, where elk that
migrated east of their winter range were exposed to highest risk from
cougars, non-migratory elk were exposed to high risk from wolves and
bears, and risk to elk that migrated west of their winter range into
protected areas was high only from bears. The patterns in predator
risk were consistent with changes in the migratory tactics in this
population.
- The scat-based approach we present permits broad-scale inferences on
predation risk for prey species that has advantages especially in
multiple predator species.