Soon after the 242-acre Johnson Ranch opened to the public a year ago, it became one of San Luis Obispo’s most popular open-space parks.
Now, resource managers are struggling with a vexing problem — wild pigs. Dozens of the animals have taken up residence in the park, where they are muddying creeks and tearing up hillsides.
The city is trapping and killing the pigs. But a hiker who came across several distressed animals caught in a trap is criticizing the eradication program.
“It’s quite a problem; I wish we didn’t have it,” said Neil Havlik, the city’s natural resources manager.
The problem began a year and a half ago. The pigs first rooted along Dry Creek, a small stream that runs through the park.
This got the attention of city biologist Freddy Otte. The pigs are releasing sediment into the creek, which is habitat for federally protected steelhead trout.
“Millions of dollars have been spent in this area improving streams for this endangered species,” Otte said. “Now, we have pigs destroying that habitat. They’re just destructive by nature.”
The Johnson Ranch is the only one of the city’s 13 open-space areas that has a pig problem. But it is getting progressively worse.
Dozens of the animals have been seen there at various times. They come out mostly at night and use several game trails that crisscross the ranch to access adjacent properties.
Wild pigs were introduced to California nearly a century ago in Carmel. They are mostly a combination of European wild boar and feral domestic pigs. Adults can weigh more than 500 pounds.
They have become a popular big-game species and are found in most woodland and foothills areas of California. However, the state Department of Fish and Game also considers them to be a major environmental threat.
It summarized the problem in a recent resource assessment of the Central Coast:
“Feral pigs root in the soil, creating excessive soil disturbance and decimating native plant communities. In oak woodlands, feral pigs can inhibit the germination and growth of young oaks by eating acorns and oak seedlings and removing leaf litter, causing soils to dry out.”
The pig problem at Johnson Ranch took on a public safety dimension recently when a woman hiking through the park surprised a sow and her piglets. The sow charged at the hiker, but the woman’s dogs chased the pig off, and the woman escaped unharmed.
“Johnson Ranch is one of the city’s crown jewels,” Otte said. “If someone was charged and mauled by a pig — well, we just can’t let that happen.”
Park rangers have a depredation permit from the state that allows them to kill the pigs. They unsuccessfully attempted to hunt them using spotlights. In January, they received a new permit that allows them to trap the animals.
The trap is a large cage. Animal feed is used to lure the pigs into the trap. While feeding, the pigs dislodge a metal bar linked to a trip wire that closes the trap behind them.
Rangers or game wardens check the traps several times a day when they’re in use. Five pigs have been trapped so far. When pigs are trapped, they are shot in the head and field dressed.
The permit allows the city to either bury the carcasses on the property or donate them to charity. City officials are trying to work out a way to donate the meat to the homeless shelter or the Prado Day Center.
“We are trying to do this humanely,” Havlik said. “It’s a very difficult situation for us.”
Originally, the trap was placed along the creek bank near one of the park’s 4 miles of hiking trails. Cindy Lossing of San Luis Obispo was hiking several weeks ago and passed by the trap while a pig and several piglets were still in it.
Panicked by being confined, the pigs were squealing and trampling each other, Lossing said. Upset by this spectacle, she has become a critic of the trapping program.
She thinks it is unnecessary and will ultimately be ineffective because the pigs range over a territory much bigger than the Johnson Ranch.
“Nature is dangerous,” she said. “If people don’t want the wilderness, then hike in Meadow Park.”City officials have since relocated the trap away from the trail. The pigs themselves cannot be relocated because they are a destructive introduced species, and no one else will take them, Havlik said.
City officials concede that it may be impossible to remove the pigs entirely from the ranch. They want to at least keep their numbers under control to minimize the damage they cause.
“We don’t really see any alternative,” Havlik said. “They go after these oak woodlands and just tear them up.”
Reach David Sneed at 781-7930.