Volume 192, December 01, 2015, Article number 6526, Pages 101-108
a
Washington State University, Pullman, WA, United States
b University of Idaho, Moscow, ID, United States
b University of Idaho, Moscow, ID, United States
Abstract
Apparent competition,
or predator selection for rare secondary prey instead of abundant
primary prey, is causing prey declines in many species worldwide. The
causal mechanism for apparent competition is either lower intrinsic
growth rate in the secondary prey or higher disproportionate predation
by predators for secondary prey. Harvest regimes which target male
carnivores are now widely accepted to result in increased sexually
selected infanticide (SSI) because of rapid male turnover and
immigration by non-sire males, and sexually segregated habitat use
because of female avoidance of infanticidal males. If harvest regimes
which target male mountain lions cause increased SSI and sexually
segregated habitat use by females with young, it could also cause
inverse prey switching by females with young or apparent competition in
declining secondary prey. We tested for inverse prey switching by female
mountain lions with young - from abundant increasing white-tailed deer at low elevations to declining mule deer
at high elevations in a heavily hunted, sexually segregated population
of mountain lions. The "no effect of targeted male harvest" hypothesis
predicts that none or all sexes and reproductive classes of mountain
lions will select for mule deer. The "targeted male harvest effect" hypothesis predicts that only females with young will select for declining mule deer.
We rejected the "no effect of targeted male harvest" hypothesis and
accepted the "targeted male harvest effect" hypothesis because only
females with cubs selected for declining mule deer
at high elevations and only during summer, when kittens were vulnerable
to infanticide - other sex and reproductive classes selected for
abundant increasing white-tailed deer
at low elevations. We suggest that harvest regimes which focus on male
harvest to reduce predation on declining secondary prey could be causing
increased predation on declining secondary prey elsewhere. © 2015 The
Authors.
Author keywords
Apparent competition; Infanticide; Mountain lion; Mule deer; Prey availability; Prey selection; Prey switching; Prey use; White-tailed deer
Indexed keywords
GEOBASE Subject Index: apparent competition; carnivore; deer;
felid; growth rate; habitat use; immigration; infanticide; mountain
region; population decline; predation; prey availability; prey selection
Species Index: Odocoileus hemionus; Odocoileus virginianus; Puma concolor