Last summer the Alaska Division of Parks and Outdoor Recreation paid several private contractors to import invasive weeds into Chugach State Park. It wasn’t intentional. It was like hiring a plumber, then belatedly realizing he had walked through your house with excrement still clinging to his shoes from the last job.
Invasive plants are non-native species tracked into an area by humans that adversely affect natural environments or cause economic losses. Invasive weeds cost the United States more than $34 billion a year, according to an estimate made a decade ago. That figure is almost certainly higher now. Invasive weeds are spreading around the world due to the increased movement of people and their stuff.
Alaska hasn’t been overwhelmed by invasive species like the other 49 states. But we’re catching up. The Municipality of Anchorage Non-Native Plant Survey, prepared by Helen Klein and others with the University of Alaska Anchorage’s Alaska Natural Heritage Program, summarized the timing of exotic plant introductions. Only one exotic plant species per year was brought into Alaska between 1941 and 1968. Between 1968 and 2006 the rate of introduction increased to three species per year. Since 2006, an average of 10 new non-native species have been reported annually. Currently, about 14 percent of Alaska’s plant species are non-native plants that have formed self-perpetuating populations, according to the Invasiveness Ranking System for Non-Native Plants of Alaska.
Invasive weeds often gain a toehold in disturbed soils, such as road shoulders. Any time ground is broken for a new project it opens up another opportunity to introduce invasive plants. Anchorage, the largest city in the state and a locus for the movement of people and goods, is a primary entry point.
State park gets sucker punched
Though it lies on the outskirts of Anchorage, the 700 square miles of Chugach State Park have largely dodged the recent onslaught of invasive species. Until now. New developments in the park are introducing dozens of non-native plants from nearby Anchorage like sparks leaping from a catastrophic wildfire.
After a new ranger station was finished this summer near Eklutna Lake, the disturbed ground surrounding the building was soiled and seeded by Alaska Diversified Contractors. In late August, Ranger Keith Wilson took a photo of many unfamiliar plants erupting from the soil. They were common lambsquarters, an invasive species increasingly common in Anchorage but not previously found in the Eklutna drainage.
A cursory inspection identified 13 other invasive plant species growing in the freshly seeded soil around the building: scentless false mayweed, shepherd’s purse, prostrate knotweed, common dandelion, common dogmustard, foxtail barley, alsike clover, pineapple weed, common plantain, common yarrow, narrowleaf hawksbeard, white sweetclover, and yellow sweetclover. Many of these plants were already found along the Eklutna Lake Road. However, they were much less common in Eklutna Valley than in Anchorage. Common lambsquarters, shepherd’s purse and common dogmustard appeared to be new to the area.
At the other end of the park, more than 50 road miles to the south, the campground at Bird Creek used to be heavily wooded, but spruce bark beetles killed hundreds of trees in the area over the past decade. Approximately 700 dead Sitka spruce trees have been removed in the campground, leaving an elongated open area. During the past two summers, several landscaping companies from Anchorage brought in soil and seeded the opening. At least $120,000 was spent on landscaping.
By early autumn, Ranger Tom Crockett noticed a variety of non-native plants flowering in the campground. A cursory inspection found most of the 13 invasive species now growing around the new Eklutna ranger station -- plus hempnettle, yellow toadflax, common chickweed, white cockle, bird vetch, and Italian ryegrass.
In just these two “improvements,” 20 invasive species of weeds were brought into the park. Lambsquarters was the most abundant weed at the ranger station; lambsquarters, Italian ryegrass, and hempnettle were most abundant at the campground.
What’s wrong with a few weeds? Other than the millions of dollars it costs taxpayers to control them, you mean?
Consider some of the worst offenders released into Chugach State Park. Yellow toadflax can form dense colonies that displace native perennial species. It produces a toxic glucoside that is either unpalatable or moderately poisonous to livestock and presumably some wildlife. White sweetclover has made the leap from roadsides to natural areas. It forms dense stands on river gravel bars and degrades natural grasslands. It produces 14,000 to 350,000 seeds per plant. Bird vetch forms dense stands and is very difficult to eradicate once established. It invades natural areas and, like kudzu, “the vine that ate the South,” and climbs taller plants.
To anyone familiar with Alaska’s wildflowers, each of these invasive species stands out like a blinking billboard. They don’t belong in Alaska parks.
The soil spread in the Bird Creek campground came from as many as eight different locations in Anchorage, according to Glenn Ball with American Landscaping. None of it was composted or heated to destroy weed seeds. There is no requirement for landscaping companies to treat soil, use certified sources of seeds, or remove invasive plants from the rootballs of ornamental trees and shrubs before planting them.
Several companies were involved. Cats Eye Excavating ground wood and topsoil already churned up in the campground into mulch. Much of that work was completed last year. On patches where the mulch was too thin, American Landscaping brought in soil from Anchorage. Green Earth hydroseeded the campground, and the Lutz spruce trees were purchased from a nursery on the Kenai Peninsula.
Assuming that a commercial seed mixture would be evenly spread, the clumped distribution of lambsquarters and Italian ryegrass in the campground leads one to believe most of the bad seed came in with the soil. However, several species of invasive weeds were conspicuously clustered on the rootballs of the transplanted spruce trees. Unless landscapers are diligent, no one can claim to be completely innocent. Weed seeds are often transported to new areas on equipment used in contaminated areas.
At least 168 invasive plant species have been found in Anchorage. Any soil or earth-moving equipment from Anchorage should be immediately suspect unless the operators wash tracks and tires between jobs.
State lagging behind US control efforts
As the threat of invasive species increases and the cost of controlling outbreaks spirals higher, public agencies have grown concerned. The cost of controlling invasive species in Alaska averaged about $5.8 million annually from 2007 to 2011. According to a 2012 analysis by the University of Alaska’s Institute of Social and Economic Research, during this period the federal government paid 84 percent while the state paid only 5 percent of the costs. Most of the rest of the burden was shouldered by nonprofit organizations. Local governments kicked in about 2 percent.
Some invasive species are worse than others. The U.S. Forest Service has developed an “invasiveness ranking” for Alaska’s non-native plant species. Based on these scores, white sweetclover is considered “extremely invasive.” Bird vetch is considered “highly invasive.” Yellow toadflax, yellow sweetclover, and foxtail barley are “moderately invasive.” Compared to these species, the scourge of the urban lawn, the common dandelion, is “modestly invasive” and its brothers-in-arms, plantains and chickweeds, are only “weakly invasive.”
Since statehood, the state has talked loudly about invasive species, but carried a small stick. Alaska Department of Natural Resources regulations prohibit certain species of noxious weeds (including hempnettle) and restrict the number of weed seeds from some noxious species (including yellow toadflax and bird vetch) in seed mixtures. The department’s Division of Agriculture offers high-quality seed mixes. It also tests seed mixes upon request.
But the state has no roving soil inspectors or seed cops. A state regulation specifies that “whenever anything brought into a part of the state from another part of the state or from any other state or foreign country is found to be infested with the seed of any prohibited noxious weed,” the “owner … of the shipment” will be notified and must return it to its orgin. “Anything” would seem to cover contaminated soil, seed mixes and rootballs of trees and shrubs. But enforcement seems to be complaint-driven, and few people seem to be complaining. Without proactive monitoring or enforcement, the state laws are toothless.
Most Alaskans remain clueless
The Anchorage Parks Foundation has an invasive plant coordinator, Tim Stallard, who works with agencies and nonprofit organizations, educates the public, and organizes volunteer weed pulls.
Most Alaskans remain clueless about the threat of invasive species and are unikely to volunteer for any weed pulls. It’s a pattern that has been repeated so many times that someone developed an “invasion curve” to illustrate what to expect. Between introduction and detection of an invasive weed, while the infested area is small, prevention and eradication are relatively simple. However, by the time the public becomes aware of the problem, the weed has become so widespread that eradication is unlikely and an intense effort, often expensive, is needed to control the spread and minimize damages.
Due to its remoteness, Alaska is lagging half a century behind other states in accumulating invasive species. Considering the lessons we’ve learned and the increasing hullabaloo from other states, you’d think that Alaskans, of all people, could get their act together.
But ignorance and apathy are pervasive. As Glenn Ball, with American Landscaping, pointed out, many invasive weeds are attractive plants. Ball said a homeowner once called him to ask where a guy might “buy some of that bird vetch.”
Anchorage’s invasive plant plan
The Municipality of Anchorage has finally started to consider the impact of invasive species. The Anchorage Parks Foundation and municipality cooperated on a non-native plant survey, completed in 2012 by UAA’s Alaska Natural Heritage Program.
Other than that, however, not a great deal seems to have been accomplished. The newly adopted Title 21 failed to address the control of invasive weeds, other than to refer to the state’s authority. The municipality drafted an invasive plant management plan in 2010. Unfortunately, the plan was never finalized.
Adopting the draft plan, which categorized invasive weeds by their abundance in addition to their potential invasiveness, is long overdue because it provides guidance on how to prioritize management of local invasive weeds. For example, its “A” list included invasive plants with limited distribution in the municipality. None of the plants with the highest priority for removal were found at Bird Creek or Eklutna.
The “B” list included invasive plants found throughout the municipality. Of these, white and yellow sweetclover, bird vetch, and yellow toadflax were found at Bird Creek and Eklutna. “Preventing the spread of these species outside of the municipality and into critical habitats within the municipality is a high priority for management,” the draft plan asserts. “Control and containment efforts must be focused along transportation corridors, near to or on public lands, and on outlying infestations.” Bird Creek and Eklutna fit all three criteria.
Most of the other invasive species found at Bird Creek and Eklutna were included on the “C” list, where control “is encouraged where practical to reach desired site conditions.” Arguably, the “desired site condition” for a state park is weed free.
Mopping up poopy footprints
Last week a crew from American Landscaping spent three days pulling weeds in Bird Creek campground. Unfortunately, they won’t remove every invasive weed. Crockett estimated they removed about half. Many of the weeds were going to seed by early September. Yanking them out will probably shake seeds loose, so more plants will reappear next summer, long after the contractors have washed their hands and moved on to other jobs.
Some invasive species seeds can survive in soil for decades. Crockett is the only park ranger assigned to Turnagain Arm. He’s well aware of the difficulty of controlling invasive species once the genie is out of the bottle. “I have started to pull weeds,” Crockett said in early September, “but am well into seed-drop season, so I’ll be doing it next year as well.”
Rick Sinnott is a former Alaska Department of Fish and Game wildlife biologist. The views expressed here are the writer's own and are not necessarily endorsed by Alaska Dispatch. Contact him at firstname.lastname@example.org