Purple loosestrife is shown in bloom. The plant, introduced from Europe for its ornamental flowers, could become a concern for Kenai fisheries because of its ability to choke off waterways.
Photo courtesy of USDA NRCS Wetl
Alaska has largely sidestepped the establishment of noxious weed species, a problem that costs millions in taxpayer dollars in the United States every year. But weeds are gaining ground and if not controlled could plunder Alaska’s economy and biodiversity.
“In all of the 50 states Alaska is the last place to do it correctly. ... We’re the last chance to get it right,” said Janice Chumley, an integrated pest management technician for the University of Alaska Fairbanks Cooperative Extension Services office in Soldotna.
This week marks the seventh annual National Invasive Plants Awareness Week and although many once thought Alaska’s cold climate and relative isolation would act as natural boundaries to invasive species, Alaskans are slowly awakening to a new reality.
“Recently you can see by some of the infestations that, that might not be clear thinking,” she said.
In Alaska, Anchorage is a biological hot spot for the proliferation of invasive plant species. And as Anchorage’s next door neighbor, the Kenai Peninsula needs to be on the watch not only for invasive species that have already arrived, but also for species in transit from Anchorage.
“We’re just down the Turnagain Arm,” Chumley said.
In 2003, for example, U.S. Forest Service employees, just south of Anchorage along the Turnagain Arm, discovered three spotted knapweed plants, an invasive species that had not yet been discovered on the peninsula. Spotted knapweed has ruined millions of acres of crop land and biodiversity in the Lower 48, including 3 million acres in Montana alone.
Millions of dollars have been spent trying to control the spotted knapweed in the Lower 48 and recent discoveries of the plant in Alaska have raised red flags.
The two- to four-foot-tall plant produces pink to purple flowers, is an aggressive invader and capable of living in a wide range of environments.
“This has the ability to change a lot of the areas in Alaska and on the Kenai Peninsula that we know and love,” she said.
When an invasive plant species establishes itself it can compete with and dominate native vegetation and crops, choke waterways and even alter the pH balance of waterways.
The purple loosestrife, for example, a six- to eight-foot-tall plant introduced from Europe for its ornamental flowers, could become a special concern for Kenai fisheries because of its ability to choke off waterways.
“All the tributaries that the fish rely on for spawning would be changed,” she said.
Although most invasive species have quietly hitched their way to Alaska on boats, planes and vehicles, many were brought here intentionally by people, charmed by their pretty flowers.
“(They say) I don’t know what it is, but I like it,” Chumley said. “People really need to be aware of what they are growing.”
This list of flowers includes the purple loosestrife and orange hawkweed.
In the case of the purple loosestrife, gardeners have been planting it in the belief that the plant’s seeds could not survive the winter to produce a new generation on their own and, therefore, not would not create an invasive species problem.
And until recently, they did not. But through successive generations the purple loosestrife has adopted and last October biologists discovered that purple loosestrife plants in the Anchorage area had produced seed that could survive the winter.
The orange hawkweed, already abundantly visible along roadways on the peninsula, has also been gardened in Alaska for its flowers, shaggy little heads of fiery-orange petals.
These plants are particularly difficult to remove, since they produce seeds that can survive for as long as seven years.
“You’re going to have to be digging for the next seven years to get rid of it,” Chumley said.
The infestation has grown particularly problematic in Homer.
“There is no vegetation left at the Homer cemetery. It’s just a mat of orange hawkweed,” said Sue True, district manager for the Kenai Soil and Water Conservation District.
The state’s antiquated weed laws and lack of enforcement are obstacles facing efforts to prevent the spread of weeds in Alaska, True said.
According to Chumley Alaska’s weed laws were last updated in 1987.
Outdated weed laws ignore species that are an obvious cause for concern in Alaska, and should be expanded to address additional species, they said.
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