By Joshua Rapp
Landfills may bolster wild pig numbers by providing a supplemental food source, increasing their size and boosting reproduction.
The giant trash heaps might also serve as vectors for the transmission of diseases and cause an increase in vehicle collisions nearby.
“Nobody is highlighting this problem of wild pigs and landfills,” said TWS member John Mayer research and development manager for the Savannah River National Laboratory of Savannah River Nuclear Solutions LLC.
Mayer has been studying wild pigs (Sus scrofa) since 1973. While talking with his colleague John Kilgo from the U.S. Forest Service Southern Research Station, also a TWS member, who was running telemetry tracking research on wild pigs in South Carolina, the two noticed the swine’s massive size after a landfill was put into the U.S. Department of Energy’s Savannah River Site in 1998.
“These things were huge, much larger than some of the pigs we usually see on the site,” Mayer said. “There was something going on at that landfill that was out of the ordinary.”
In a
study published recently in the Journal of Wildlife Management, the two researchers and others looked more deeply at the effects of the landfill on wild pigs.
Signs like this surrounding the landfill at the Department of Energy’s Savannah River Site were the among the first put up in South Carolina.
They found that pigs were indeed getting bigger from 2000 to 2019 compared to their size 20 years before the landfill was created. They also noticed an increase in litter size around the landfill compared to wild pigs in the general area.
The density of wild pigs harvested in a given area also increased by nearly three times, and vehicle collisions involving hogs began happening in areas that had previously experienced none.
“The pigs foraging in the landfill get bigger,” Mayer said. “That creates two problems: Bigger sows create bigger litters, and bigger pigs in general cause bigger risks with respect to vehicle collision.”
In the 310-square-mile area that includes the landfill, Mayer estimates there are more than 5,000 wild pigs.
The damage wild pigs cause ecologically is well-documented. They are ecosystem engineers, changing wetland ecosystems and outcompeting native species for food. They can also uproot crops and cause other agricultural damage.
But Mayer worries that landfills could be the source of even more pig damage, become a flashpoint for the spread of a disease that has devastated the pork industry in countries across Asia and Europe — the African swine fever. While this disease has yet to be detected in North America, some researchers believe it’s just a matter of time before the disease makes the jump.
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