Introduced wild pigs affect the foraging ecology of a native predator as both prey and scavenger

Introduced species can disrupt trophic interactions by acting as novel
predators, prey, or scavengers. Predicting impacts of these disruptions
can be integral to conservation of native species and maintenance of
ecological function, but it is challenging, especially for species
involved in multiple trophic interactions. Wild pigs (Sus scrofa) are a
widely introduced ungulate that can function as prey, predator, and
scavenger, and disrupt ecosystems through many pathways. One underexplored
avenue is how wild pigs alter predator-prey dynamics of mammalian
carnivores. We explored how wild pigs affect cougar (Puma concolor)
foraging ecology as both prey for cougars and scavengers of cougar kills.
We monitored cougars in an area with wild pigs to evaluate impacts on
cougar habitat selection, diet, and feeding behavior. We also monitored
wild pigs scavenging at cougar kills to understand if scavenging by pigs
affects cougar feeding behavior or kill rates. Habitat selection patterns
indicated cougars selected for areas based on both landscape factors and
prey density, but selection was stronger for native black-tailed deer
(Odocoileus hemionus columbianus) than for pigs. We also documented that
wild pigs, especially juveniles, were an important secondary prey item for
cougars. Finally, we observed that wild pigs scavenged large prey items
killed by cougars, which led to reduced feeding time by cougars at
individual kills. However, wild pigs did not scavenge frequently enough to
affect cougar kill rates. Our research highlights multiple impacts of wild
pigs on cougar ecology, both as prey and scavengers, to illustrate how
wild pigs disrupt ecosystems. Areas with a higher density of pigs or a
lower density of native prey would likely see stronger impacts of wild
pigs on predator-prey interactions, and management of wild pigs should
account for these interactions, especially when native predators or prey
are species of conservation concern.