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Invasive waterweed has Alaska ecologists, homeowners and aviators concerned

Devin Kelly
Canadian Waterweed, Elodea canadensis (with enlarged cross section of a single whorl). In this instance, the leaves are relatively long and narrow (four times longer than wide).
Christian Fischer
Flowering Canadian Waterweed (Elodea canadensis) in a shallow ditch. The plants have partly become encrusted in lime, apparently. That's why the leaves' surface look somewhat covered, in this case.
Christian Fischer

For several years, residents of the homes lining Sand Lake in South Anchorage watched as the water turned steadily greener.

Tangles of weeds wrapped around the rudders of float planes and choked the canal area. The bottom of the lake eventually vanished from view.

Alaska's first known submerged invasive aquatic plant species was on the move, the latest salvo in what has been described as a burgeoning war of the waterways, stretching from Southcentral Alaska to the Interior.

Since 2010, a slew of government agencies have mobilized to fight the spread of elodea, a fast-growing invasive also known as western or Canadian waterweed. Ecologists warn that the plant, known for its dense growth and high cold tolerance, threatens boating, float plane and commercial and sport fishing enterprises and could eventually affect fish species in water bodies across Alaska. With the invasion still contained to a relatively small number of waterways, members of the ecological research community are urging a quick response.

But no statewide management plan exists yet, and the fight is complicated by funding shortfalls, questions over eradication methods, and the absence of past experience with invasive aquatic plants.

"We're just now starting to ... figure out the seriousness of this problem," Ed Fogels, deputy commissioner of the Department of Natural Resources, said at a public meeting in Sand Lake this month. The Department of Natural Resources' division of agriculture formally took charge of the state's elodea response in January.

House Bill 89, introduced in January to create a rapid response and management plan for invasive aquatic species, failed to get as far as the House floor in 2013. The legislation will be taken up again in the next session in Juneau.

Regional approaches, meanwhile, have varied in scope and aggressiveness.

A troubling presence

Elodea, a slender plant with whorled leaves, has been identified in four main areas in Alaska: Eyak Lake in the Cordova area, where the plant was first documented in 1982; and, since 2009, Chena Slough, Chena Lake and parts of the Chena River in Fairbanks, several lakes in the Kenai Peninsula, and lakes in Anchorage, including Sand Lake.

The two species of elodea documented in Alaska are native to parts of the Lower 48 and Canada. Infestations of elodea have cropped up in the British Isles, where it was first introduced as an ornamental plant more than 100 years ago, and it has also spread to Scandinavia and Russia, according to a 2011 paper written by U.S. Forest Service employees.

Elodea's popularity as an aquarium plant and specimen in school and university biology supply kits is considered the leading reason for its uninvited presence in Alaska waters. The Anchorage School District uses science packets containing elodea for microscope examination lessons.

Now, warnings accompany those science packets: Do not let this plant enter Alaska waters.

In recent years, the weed has overtaken a small number of waterways popular as recreation spots, and government officials and invasive species managers worry about a potential effect on salmon and other species that breed in freshwater lakes and rivers. The state is still collecting data to figure out the extent of those marine life risks, said Brianne Blackburn, a natural resource specialist with the Department of Natural Resources and a coordinator for the elodea response.

In Fairbanks, the rapid growth of elodea in Chena Slough has frustrated canoeists and fly fishermen and prompted concerns over grayling habitat.

In 2011, after participating in an elodea work group in Fairbanks, Cecil Rich, the statewide coordinator for the U.S. Fish and Wildlife Service's invasive species program, struck out on a July weekend to find out if elodea had also made its way to Anchorage.

He went to Lake Hood in Spenard first, and found nothing. Then he visited Sand Lake and walked around the shoreline, where he spotted the weed growing in large fans. DeLong Lake and Little Campbell Lake also contained traces of the plant.

The Anchorage invasion apparently dates back five to 10 years, Rich said.

A range of approaches

This month, a group of government officials met at Sand Lake Elementary School in Anchorage, aiming to update property owners on the still-evolving elodea response plan.

About 20 people listened as Lars Anderson, an aquatic invasive species expert who has worked with the U.S. Department of Agriculture's Agricultural Research Service, flipped through a series of slides on how invasive aquatic plant species have been tackled in other states.

On a regional basis, the most decisive action so far in Alaska has occurred in Kenai, where agencies have dealt with invasive land plants in the past. Last fall, elodea was discovered in Stormy and Daniels lakes, and this summer, it was found in a third, Beck Lake, said John Morton, supervisory biologist at the Kenai National Wildlife Refuge.

Morton and others have moved quickly for permits for two herbicide treatments for the lakes. Within the next three years, at least three treatments are planned -- two whole-lake treatments for Stormy and Beck lakes, and a partial treatment for Daniels Lake, which is near homes.

The chief herbicide of choice, fluridone, kills the plant at low concentrations and is selective, making it a chief tool for eradication, Morton said. A second chemical, diquat, kills more quickly but doesn't discriminate on the type of plant, he said.

A permit for diquat application has already been approved, and authorities are working on an application for fluridone, Morton said.

"We're really fast-tracking it," Morton said, stressing that the goal is eradication, not control.

It's a pricey route -- the herbicide product alone costs $600,000, Morton said. The Kenai Peninsula Borough is asking the state legislature for $700,000 to confront the problem.

Experts warn that delaying the response could lead to even larger bill down the road.

Other methods tested so far include mechanical removal through suction dredging, which saw trials in Fairbanks this summer. Officials and researchers there are still debating the use of herbicide, particularly for areas where the water is flowing, such as the slow-moving Chena Slough.

Joni Scharfenberg, district coordinator for the Fairbanks Soil and Water Conservation District, said the district is hoping to work with the Alaska Department of Environmental Conservation for a declaration of "impaired waterways" in Fairbanks, which could open up more grant opportunities.

The Alaska legislature has so far approved $115,000 in funds to combat elodea in Anchorage and $70,000 in Fairbanks.

Slow progress in Anchorage

More than two years after Rich first spotted elodea in local lakes, no specific course of action has emerged in Anchorage. A meeting to discuss options with property owners will take place in January, Ryan Stencel, operations manager for the Anchorage Soil and Water Conservation District, said at the December meeting.

"We feel like there are a whole lot of unknowns out there," said Bret Burroughs, chair of the conservation district board of supervisors. He said the district is concerned about the whole health of the lake, not just elodea.

Homeowners who live near Sand Lake also say they'd like to see more progress on the research front before decisions are made.

"I wasn't convinced about the science being fully completed," said Robert Bloomfield, who attended the meeting.

But he also said he has to put his float plane down in the past because of weeds clinging to the rudder.

Those clinging weeds worry officials and scientists, who say elodea, which reproduces asexually, is easily transported and introduced into other places by planes or people -- places that may not yet be obvious yet. Roger Chan, who also lives on Sand Lake and also attended the December meeting, flies a float plane and said he's worried about spreading elodea unintentionally.

As different agencies wrestle with the right way to move forward and look to the state for clues, worried biologists like Morton point to a grim learning experience.

"We have to get our lessons learned right now, because elodea is only the tip of the iceberg," Morton said. "There are a bunch more coming."

Reach Devin Kelly at dkelly@adn.com or 257-4314.

Editor's note: An earlier version of this story misspelled the last name of Ed Fogels, deputy commissioner of the Department of Natural Resources. The story also incorrectly reported that Campbell Lake is one of three Anchorage lakes where Elodea has been detected. The three lakes are Sand Lake, DeLong Lake and Little Campbell Lake.

 


By DEVIN KELLY
dkelly@adn.com