MIDDLE TOWNSHIP — Three Bradford pear trees on the grounds around an old farmhouse here were probably planted by a former owner for their glorious white flowers. But those pear trees’ days are numbered: The farmhouse and the trees are now part of the Cape May National Wildlife Refuge, which plans to chop them down to stem the spread of invasive species.
From feral pigs rooting up golf courses to foreign diseases wiping out oysters and backyard flowers going rogue in woods across the state, New Jersey is under invasion. For years the state’s wildlife managers have worked to save wild plants and animals on the verge of extinction. But more and more, they are examining new ways to cope with exotic plants and animals that are faring all too well in the Garden State.
The sprawling Cape May County refuge focused last year on eradicating English ivy, which was commonly planted in back yards in New Jersey. Despite the agency’s toils, Heidi Hanlon, a biologist with the U.S. Fish and Wildlife Service, found some of the blackish-green ivy still clinging to a cherry tree after a little searching near a field. Like multiflora rose and Japanese honeysuckle, the ivy crowds out native species that birds and wildlife rely on for food or cover, Hanlon said.
A state panel composed of biologists, professors and farmers last month submitted a report on invasive species to former Gov. Jon S. Corzine. Among the group’s recommendations: Prohibit the sale of invasive or potentially invasive plants. Some of the flowers and shrubs people buy for their landscaping reproduce and end up growing freely in the wild, where they crowd out native plants.
The report contained a list of invasive or exotic species and also proved controversial, since many of these so-called invaders are big sellers at garden centers and nurseries.
“The nursery industry isn’t happy about the list,” said George Dean, owner of Dean’s Evergreens in Gloucester County.
He and other growers said restricting what New Jersey nurseries can sell would hurt an industry already struggling through a recession and housing slump.
“The nursery business is more of a luxury. People are more concerned about their dinner tables than their rose gardens right now,” Dean said. “There’s no easy solution. The nursery industry has to get proactive and come out with solutions before regulations come down.”
Nurseries are the No. 1 cash crop in New Jersey, with landscaping plants accounting for about 40 percent of the state’s agricultural production — all fueled by development and suburban green thumbs who spruce up their yards every spring.
“We have some members who are 100 percent against placing restrictions on invasives. We have some 100 percent for it. But a majority are somewhere in between,” said Carl Quazza, director of the New Jersey Nursery and Landscape Association. His group represents about 750 companies.
But state and federal agencies are spending millions of dollars each year trying to eliminate these same plants adorning mulched gardens.
New Jersey is home to 32 of the nation’s 46 most common invasive plants that can cause agricultural or environmental harm, according to the USDA. The state is a port of entry for commerce and a heavily traveled route between Pennsylvania and New York, giving invasive plants plenty of opportunity to hitchhike. Refuges such as Cape May pay special attention to killing invasive plants along roadsides because they spread faster there.
“The problem of invasive species is worse here than in a lot of places,” said Troy Ettel, conservation director for the New Jersey Audubon Society. “That’s why it’s so important we’re so vigilant, not just for New Jersey but for other states.”
The state Department of Environmental Protection estimates that agricultural weeds and other invasive pests cause $290 million each year in damage to farms and natural areas.
Focus on deer
Invasive plants such as Japanese barberry are prized in large part because they don’t taste good to deer, Quazza said.
“The biggest concern is: Will the deer eat it? That’s more of a concern to the retailer and end user than is it invasive,” he said.
The appetites of hungry deer can decimate native plants, paving the way for foreign invaders, said consultant Michael Van Clef, who wrote the invasive species report for the state panel.
“A lot of these things are weeds in the truest sense. They are generalists that do well when an environment is disturbed,” he said.
“People say the invasive species are more competitive. No, they’re not. They just don’t get eaten. I’ve seen infestations get reversed when the deer population goes down.”
Plants with names like mile-a-minute weed and purple loosestrife are useless to most native insects with repercussions up the food chain, Van Clef said.
In extreme cases, the plants pose a threat to human health. People who touch the sap or juices from Giant hogweed can develop blisters and even permanent scars on their skin.
“It’s a very unusual-looking plant. I’ve seen it used as an ornamental,” Van Clef said. “It causes blistering, festering wounds, and they had it planted next to an ice-cream stand.”
His report suggested the state reduce the deer population, create a “strike team” to identify and eliminate pockets of invasive species while they can be contained and lobby for stricter federal screens at the country’s entry points.
Collapse of an industry
Invasive species are hardly restricted to plants. New Jersey is still recovering from one of the worst economic disasters caused by foreign invaders here.
Two parasitic diseases, commonly called MSX and Dermo, migrated to Delaware Bay oyster beds in 1957 and 1990, respectively. The warm-water diseases killed off 95 percent of the bay’s oyster stock.
“Prior to the 1950s the oyster industry drove a lot of the economy in this part of New Jersey. So when that collapsed, it was devastating to the area,” said David Bushek, an associate professor at Rutgers University.
Bushek, an expert on shellfish ecology and pathology, works at the Haskins Shellfish Research Lab in Commercial Township. The lab is working on developing disease-resistant oysters, locally known as Cape May salts. The lab just completed a four-year study examining how oysters naturally survived their bouts with the disease.
“It’s harder to breed for natural selection for resistance for reasons that are not completely clear to us,” Bushek said.
The lab’s efforts appear to be working, he said. Last year’s survey of oyster beds showed the population was holding its ground, sustaining an annual commercial harvest, he said.
“If we can overcome this problem with Dermo, we should see a good recovery,” he said.
A pig problem
For the past 15 years, Gloucester County has had a pig problem. Some wild hogs that either escaped or were released in Franklin and Monroe townships made themselves at home near White Oaks Golf Course.
A few generations removed from farm life, wild pigs look less like Babe than an Arkansas razorback, with coarse fur and tusks they use to dig up roots and grubs. Between 40 and several hundred of the feral hogs are believed to roam the woods.
“They call them ‘living Rototillers,’ ” said Nicole Rein, a wildlife specialist with the U.S. Department of Agriculture in Egg Harbor Township.
Living up to the pig’s reputation, these hogs are not picky eaters.
“It would just take a few pigs a few hours to destroy a field. They can destroy a golf course looking for grubs and earthworms and acorns. They will eat anything. They definitely have an economic impact,” she said.
Golf course employees were puzzled by the first signs of damage they noticed five years ago along the rough edges of the course, owner Eric Dobson said.
“We didn’t know what they were. We just saw the damage they left behind,” he said.
Pigs in the wild can contract diseases such as swine fever that can be transmitted to domestic pigs.
Experience in other states shows it does not take long for a minor annoyance to become a major catastrophe. The last comprehensive feral swine census counted 4 million across 30 states, especially in Texas, Florida, California and Hawaii, where they cause hundreds of millions of dollars in damage to agriculture each year.
After seeing what just a few pigs can do to a golf course, Dobson said, “The damage could be devastating.”
New Jersey opened a hunting season on the pigs last year. The goal: complete eradication. But since pigs produce big litters and the herds are skittish around people, wild hogs could be here to stay.
Fish tank trouble
A common aquarium plant is poised to wreak havoc on the Maurice River watershed.
Called parrotfeather because of the delicate beauty of its fronds, this invasive plant from the Amazon basin grows like a beast when loosed on American waterways.
The plant’s thick vegetation can choke creeks, blocking sunlight and lowering the amount of dissolved oxygen available to fish.
“It’s an unfortunate new find in New Jersey,” said Renee Brecht, associate director of the nonprofit group Citizens United to Protect the Maurice River and its Tributaries.
“It’s a concern because in other states it’s a real problem.”
A boater first detected the plant last year after she noticed it was clogging up her boat dock. Further investigation found the plant growing for more than a mile in the Menantico Creek, which feeds the Maurice River. The nonprofit group is working with the Vineland Environmental Commission and the U.S. Fish and Wildlife Service to kill the plants.
Brecht said the mile of choking plants probably originated from a single home aquarium someone dumped in the creek. Once loose, the plant is especially tough to kill because of the way it reproduces.
“It doesn’t reproduce by seed but by fragmentation,” Brecht said.
Little pieces that are broken off the main plant float downstream and grow anew through rhizomes.
Brecht said at least one Cumberland County kayak livery has agreed to direct customers away from the affected stretch of creek this summer to help keep the plant in check, she said. Parrotfeather could be a disaster in the making for recreational boaters, she said.
Nothing prevents aquarium suppliers from selling the plants in New Jersey. Some But some Internet retailers now post warnings to customers about invasive species and the proper disposal of unwanted aquarium plants.
Some of the most harmful invaders are the smallest: insects. Gypsy moths, hemlock woolly adelgids and emerald ash borers threaten forests with their appetites, defoliating the tree canopy, destroying pine needles or weakening hardwoods.
New Jersey is facing a relatively new threat from the Asian long-horned beetle, which arrived in New York in 1992 stowed away in wood pallets and packing material.
The beetles were found in northern New Jersey in 2002, where they made themselves at home inside hardwoods such as maple, ash and birch trees, said Rhonda J. Santos, a spokeswoman for the U.S. Department of Agriculture.
With mandibles like needle-nose pliers, the larvae tunnel through the otherwise impenetrable wood, creating gouges like bullet holes deep in the trees, she said. Beetles can quickly kill their host trees, threatening maple syrup producers and foresters.
The insects cause headaches for landscapers and nurseries who face stricter rules about removing wood from affected areas. States such as Massachusetts, New York and Pennsylvania have passed rules against importing out-of-state firewood to prevent the spread of the pests to untouched forests.
“I just spent the week in Louisville, where Louisville Slugger makes bats out of maple and ash. They get them in Pennsylvania and New York, where they need full-sized trees,” she said.
The company is on alert for the invaders, even studying what other kinds of trees might make a good substitute for baseball bats if the beetles invade the company’s harvesting sites in Pennsylvania, according to its corporate website.
And for infected trees, the best solution is a chainsaw. This has denuded some once-shady suburban neighborhoods in Union and Hudson counties.
“Unfortunately, it means the tree gets cut down. It would die anyway. But the hope is that doing that will save other trees like cutting out a cancer,” Santos said. “But think if you planted a memorial tree. For sentimental reasons, it can be sad to see the tree go.”
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