Blue Ridge Parkway ecologists tackle invasive species
By Scott Nicholson
Blue Ridge Parkway officials are developing a management plan to deal with invasive species and protect biological systems and rare plants in the national park.
Parkway rangers want input on an Exotic Plant Management Plan and Environmental Assessment which will help develop park guidelines to manage non-native species. The plan could include a mix of mechanical, physical, chemical, cultural and biological controls.
Chris Ulrey, a plant ecologist for the National Park Service, said park officials have been addressing the problem on a limited basis, but now are approaching the issue as a “major impact.” The plan will address which species should be a focus for control or eradication, how they should be controlled and ways the parkway can be protected from further invasion.
Ulrey said there were about 100 non-native species in the 469-mile park that extends from western North Carolina into Virginia. Only a dozen or so of those are causing the most concern. Among them are kudzu, garlic mustard and Oriental bittersweet, according to Ulrey, which are posing what he calls “a huge problem.”
Currently, much of the non-native plant invasion is clustered around urban areas such as Asheville and Boone, Ulrey said. Typically, the plant is an ornamental shrub that has spread or whose seed has been carried by birds into the parkway habitat. The non-native plant often has a biological advantage over the native plants because it has no natural predators or controls.
“They’ve had controls in their native setting, but they are out competing species here,” Ulrey said. Some species create their own advantage, such as Oriental bittersweet, which can grow up and cover a tree, adding weight that makes it more susceptible to falling. Once the tree falls, more light reaches the forest floor, enabling the vine to grow even better.
Even a plant with such potential to infiltrate an ecosystem doesn’t always get ostracized. Ulrey said an effort to limit cultivation of Oriental bittersweet was resisted by the Christmas tree industry, which uses the vine in wrapping wreaths, so it remains commercially available.
Ulrey said other invasive species are still available in the commercial horticulture trade, which makes it more difficult to combat them in the wild. A species like garlic mustard is often considered attractive by the casual observer, but quickly takes over, Ulrey said. It also releases a chemical into the ground that inhibits the sprouting of native plant seeds, further gaining a competitive advantage.
Another factor in the battle is the terrain and map of the parkway. “It’s a long, skinny land mass,” Ulrey said. “Even if we get rid of everything, it wouldn’t take long for it to come back. It’s going to take cooperation from adjoining areas.”
Ulrey said a park like the Great Smoky Mountains is easier to protect because the park is large and doesn’t have long boundaries. Even then, fighting off invasive species can be difficult. Ulrey said some plants can be easily eradicated by digging them up, but that takes workers and volunteers, as well as persistent effort of monitoring. Though some can be hand cut, most of them require herbicides.
Ulrey said it’s a high-priority issue requiring a creative approach. With the park service budget remaining relatively flat, money for chemicals and equipment will have to be used wisely. Priority will be for those areas with the most rare native species. Ulrey said while botanists look at a wide range of pests, each type of threat has its own plan, and he said most of the input on the plan is from those knowledgeable about the problem. He said it’s also an educational issue, because most people aren’t aware of the threat some ornamental, imported plants have on the habitat.
“It’s far more than an aesthetics issue,” Ulrey said. “It’s a biological issue. There’s still a lot of education to be done. Just in the last five years, there’s been a lot of media exposure for the problem.”
The plan is available for review and comments at parkplanning.nps.gov.
Comments can also be submitted by mail to Blue Ridge Parkway, ATTN: Suzette Molling, 199 Hemphill Knob Road, Asheville NC 28803.
Ulrey said even with a sound management plan, it might be a losing battle. “If the trend continues, we’ll probably have to throw in the towel,” he said. “Whether it’s five years or 50 years. You just can’t work on your land with blinders on. Everyone’s really going to have to work together.”