Foreign flowers and shrubs invade native species in Garden State

on July 26, 2009 at 1:39 PM, updated July 26, 2009 at 1:49 PM

New Jersey is under attack.

Flowers, shrubs and weeds brought here from foreign shores are pushing out native plants and damaging delicate ecosystems.

Invasive species are the No. 2 threat to biodiversity worldwide, second only to outright habitat destruction, according to Melissa Almendinger, invasive species coordinator at the Upper Raritan Watershed Association.

"There are some native plants that are just lost," Almendinger said. "On a global level, we're creating a monoculture."

The invasion of aggressive, exotic plants has an impact on everything, Almendinger said. Less variety of plants means less variety of animals. Migration patterns are changed. Soil chemistry also is altered, usually in a way that favors the invasive species and affecting what can be grown.

Not all exotic plants are considered invasive, Almendinger said, only those that grow densely and exclude other species over large areas. But, she added, all non-native plants have that potential.

Of the 1,000 foreign plants that have been introduced to the state, 30 are classified as "widespread" invasive species, including the shrubs multiflora rose and Japa- nese barberry. Another 71 have been identified as "emerging" invasive species. And the rate of new plant introductions continues to rise, Almendinger said.

The recently formed Central Jersey Invasive Species Strike Team is searching for and identifying these new invasive species in Hunterdon, Morris, Mercer and Somerset counties. Its job is to eliminate them before they spread out of control, Almendinger said.

She is leading the effort, with URWA staff and volunteers from the Friends of Hopewell Valley Open Space in Mercer County. The team has 37 other partners that include their land in the project and contribute labor.

Begun last summer, "it's really taken off this year," Almendinger said.

The strike team's method is called early detection and rapid response. First, volunteers head into a field armed with GPS units, plant identification books and cameras. They collect data and enter it onto a map. Then Almendinger or volunteers return and cut down the plant. She said she sometimes places herbicide directly onto the stump to ensure its destruction.

The strike team faces an especially big job this fall right in its own backyard. Members plan to eradicate 2,000 linden viburnum -- a landscaping plant with white flowers and red berries -- that have overtaken its Bedminster headquarters' driveway.

The team's mission has been lauded by Kathleen Salisbury, president of the Native Plant Society of New Jersey.

"I think the work they're doing is especially significant because they're trying to identify the upand-coming invasive plants," Salisbury said. Instead of hacking away at things that are already out of control, "they're trying to nip it in the bud," she said. "There's nobody else in the state that I know of that's doing anything like that."

URWA hopes education is the key to getting people to remove invasive species from their property and demand native plants.

"Some of these plants like burning bush are the bread and butter of the landscaping industry," Salisbury said.

In just two years, invasive plants have launched a full-out attack on the 70-acre Helyar Woods of Rutgers University's Cook Campus, said Bruce Crawford, director of Rutgers Gardens. In an area where a number of trees died a few years back, he noticed the rapid spread of two plants: ailanthus and paulownia. These invasive plants grow at a rate of six feet a year, while the oak and beech trees that used to make up the forest grow only about six inches to a foot a year, Crawford said.

At URWA's headquarters in Bedminster last week, Alemdinger said another problem with invasive species is they tend to have weaker, shallower root systems, so they don't do as good a job of preventing erosion or filtering ground water. Ironically, many invasive species, such as autumn olive, were introduced by the federal government to prevent erosion because they grow so quickly, she said.

Almendinger also blames deer for the destruction of native habitats. "The deer browse all native tree and shrub seedlings, preventing them from getting established," she said.

"Long term, this means that as the mature trees die there will be nothing left to replace them and entire patches of forest will either be lost or completely replaced by invasive trees and shrubs." And by destroying native plants, deer are destroying the food sources of native animals.

Some people are surprised that an organization committed to environmental conservation supports deer hunting, Almendinger said. She said she responds by saying that supporting deer hunting is actually saving the lives of other animals.

After the state's deer herd is cut back, "the hope is that eventually native plants will be able to fight back on their own," she added.