Originally published in the Union College Magazine, Fall 2013
On a warm, overcast spring day, Peter Tobiessen steadied the redwood canoe he built himself and dropped a customized metal garden rake into Collins Lake in Scotia, N.Y.
“You wanted weeds?” the biology professor emeritus asked, chuckling as he pulled the tool to the surface. “Here you go.”
Like a giant fork with spaghetti twirled around its tines, the rake was covered with loops of stringy aquatic plants, mostly curly-leaf pondweed but some Eurasian water milfoil too.
It’s evidence of the obvious – Collins Lake is infested, from surface to sediment. Curly-leaf pondweed dominates during spring, milfoil during summer.
On this day, Tobiessen’s canoe seemed to rest atop the plants in water shallower than 15 feet, making a gentle rushing noise as it skimmed over them. And not infrequently, his white paddle dipped into the water only to come out with strands of leafy greenery clinging to it.
Both plants are invasive species, Tobiessen explained. And both are threats to New York’s Adirondack Mountains and Capital Region – and to environments across the country.
Tobiessen, who has been studying aquatic ecosystems since the 1970s, is one of several Union faculty members with invasive species expertise. Their work could be useful on multiple levels in the fight against what many call living pollution.
Why living pollution?
Well, perhaps one reason is this: The New York State Invasive Species Task Force reported in 2005 that, nationwide, 18 percent of federally endangered or threatened plants and animals are at risk principally because of invasive species.
What’s an invasive species?
An invasive species, as defined by The Nature Conservancy, is a non-native organism that can harm the environment, human health or the economy.
It’s important to remember, though, that non-native and invasive are not interchangeable. While all invasive species in the Adirondacks and Capital Region are non-native (not from around here), most non-native species don’t damage their adopted homes.
Plants and animals that generations of New Yorkers have grown up with – like rainbow and brown trout, and even most apple trees – aren’t native and aren’t problems.
For more perspective, approximately one-third of New York plant species are from somewhere else, according to the Task Force report, but only 10 to 15 percent of these are considered invasive.
They have that distinction, Associate Professor of Biology Jeff Corbin explained, because they are actively invading – expanding their range and their impact.
Why so bad, ecologically?
Whether the interloper is a plant, animal or fungus, invasive species are bad because they can dominate habitat and decrease the survival rate of native residents.
In severe cases, organisms especially sensitive to an invader can be almost entirely exterminated. Consider chestnut blight. Caused by a fungus and first discovered in the U.S. about 1900, it decimated American chestnut populations in just decades. Once a dominant component of many New England forests, the tree is now absent from the landscape, Tobiessen said.
Invaders making current headlines, like the Asian clam, haven’t yet caused such a catastrophe, but their presence is becoming ever more noticeable.
“First found in Lake George in August 2010, more than 27 acres of the lake – as of summer 2012 – had the Asian clam,” said Emily Delaney ’13, while presenting her research during Steinmetz Day in May.
That initial discovery was made, incidentally, by Jeremy Farrell ’03, now a graduate student and laboratory technician with RPI’s Darrin Fresh Water Institute (DFWI).
Together with Associate Professor of Biology Jill Salvo, who is collaborating with DFWI, Delaney is studying molecular detection of invasive freshwater clams and mussels. They’re developing a way to identify Asian clams, zebra mussels and quagga mussels using rRNA markers, as opposed to physical characteristics. The hope is that the method might offer a more complete picture of invader populations.
It’s an important goal in light of that fact that these mollusks reproduce like mad and can alter lakes in unsavory ways.
“Asian clams can release 300 larvae a day during breeding season, and can form dense clusters of 5,000 or more per square meter,” Delaney said. “Although Asian clams don’t attach to surfaces like the more familiar zebra mussel, they can clog pipes and cover sandy, warm, shallow areas with shells.”
In addition to water flow problems caused for industrial plants with intake pipes in lakes, this bivalve can also ruin water quality and habitat.
Their nutrient-rich excrement can stimulate so much algae growth that blue water turns green, according to a Fund for Lake George fact sheet. FLG is one of several organizations dedicated to protecting the well-known, southeastern Adirondack water body.
Garlic mustard is similarly domineering, in its own way.
“Whether we know it or not, we all see garlic mustard along Schenectady roadsides in spring,” said Corbin, who works with The Nature Conservancy to monitor the plant’s spread along the edge of the Adirondack Park. “It’s present in basically all Northeastern and Midwestern states.”
“Garlic mustard can form dense populations in the forest understory, potentially shading out other plants, including tree seedlings,” he continued. “It has also been shown to exude chemicals through its roots that disrupt the mutualism between trees and beneficial mycorrhizal fungi.”
In this partnership, the fungi get carbon from the trees while the trees get phosphorus (an important nutrient) from the fungi. There’s also evidence that mycorrhizae provide some disease resistance for trees against harmful bacteria or fungi in the soil.
“So far, it has not been demonstrated that garlic mustard can affect mature trees, but there is concern that it could reduce the survival of the next generation of tree seedlings,” Corbin said.
If that happens, the impact – decreased biodiversity – could be magnified across the entire ecosystem.
In general, native animals at the base of the food chain, like insects, need a variety of plants to eat and reproduce on. When their habitat is dominated by one foreign plant (or animal) that has no natural predator to curb its spread, the resulting monoculture makes it difficult for bugs to thrive. This may result in fewer species for larger animals (birds, fish, amphibians, mammals) to eat, which in turn could diminish the number of species living in a given environment.
These biological bullies can also affect people.
“Eurasian water milfoil can form dense stands impossible to swim through or even penetrate with a motorboat, since the propellers get entangled with the stems,” Tobiessen writes in his new book, The Secret Life of a Lake: The Ecology of Northern Lakes and Their Stewardship.
“Collins Lake, in Scotia, N.Y., has lots of weeds – milfoil and curly-leaf pondweed – that are really nasty,” he added during an interview. “We’ve literally rescued people from them when their rowboats have gotten stuck.”
And for the Adirondacks, with its outdoor-dependent tourism industry, something that erodes recreation could be cause for concern.
Just how big a cause for concern it is, however, hasn’t been established.
Bad for business?
Data that directly correlate living polluters with economic hardship in the Adirondacks are limited, making it difficult to determine how detrimental invasive species might be to the coffers of people, towns and government.
Corbin, however, is working with The Nature Conservancy to collect this kind of information.
“The conservancy is very interested in developing economic justifications for invasive species control to go along with the biological ones, like biodiversity, that they traditionally rely on,” Corbin said. “It will be a park-wide study, focused on particular segments of the economy.”
“The cost-benefit models we develop may include tradeoffs between the costs of monitoring and controlling invasive species, versus the benefits of monitoring and controlling them,” he continued. “Such benefits might be direct economic boons, like ensuring the continued viability of timber production or recreational use.”
Timber and tourism (recreation) are indeed critical to the Adirondacks. The exact nature of the link between their fiscal health and the presence of usurpers like Asian clams remains to be seen, but the economic value of wood and visitors is nonetheless clear.
According to a 2011 study conducted by Tourism Economics for Hamilton County, N.Y., tourism is more important to the Adirondacks than any other region in the state. It’s a $1.2 billion industry that accounts for 17.6 percent of total employment in the area. Broken down, Adirondack tourism generated $149 million in state and local sales taxes in 2011, and another $77 million in sales, property and hotel bed taxes.
About $220 million was also produced by the seasonal, second-home market in the Adirondacks. And this is a fact worth noting to Tobiessen.
If weeds like Eurasian water milfoil “make a lake inaccessible, property values would plummet,” he said. “Lots of folks live and boat on, and swim and fish in, lakes. They prefer clean lakes to polluted ones. If you are a lakeshore property owner, you have a financial stake in keeping your lake clean.”
Similarly, many Adirondack communities have a stake in protecting the local timber industry. According to a February article in Schenectady’s Daily Gazette, it employs as many as 10,000 people.
“Invasive insects like the emerald ash borer and Asian longhorned beetle are big worries,” Corbin said. “Neither is in the Adirondack Park yet, but it is likely just a matter of time.”
Smaller than a penny, the ash borer basically eats trees from the inside out. It’s been found south of the park in Albany County, according to the New York Invasive Species Clearinghouse. Albany, one of 13 counties known to have the pest, and 29 others potentially infected, are under quarantine. Ordered by the state Department of Agriculture and Markets, the quarantine restricts movement of regulated materials – firewood, ash nursery stock, mulch – that could hasten the spread of the beetle.
An expeditious killer, the N.Y.S. Department of Conservation notes that most afflicted ash trees die within two to four years. Mortality is nearly 100 percent – over 50 million trees have already been lost nationwide.
In 2011, the Western New York Partnership for Regional Invasive Species Management estimated that dealing with this situation would cost the U.S. $10.7 billion over the next decade.
So, bringing invasive species to heel isn’t cheap.
A pricey, challenging battle
Mountains of money are spent managing – just managing, not eliminating – these biological bullies.
“Eradication is a misnomer in most environments,” said Will Stevenson ’92, president of Lycott Environmental in Spencer, Mass. “Even if I put 10 people in a field and said, ‘Go pull out every dandelion,’ they wouldn’t get them all, and just one or two is enough to keep the population moving.”
And he would know. About 50 percent of the business Lycott does (it manages lakes, ponds and reservoirs) revolves around aquatic invasive species mitigation.
Lycott Environmental offers surveys of water bodies, and myriad methods to control unwelcome invaders – everything from herbicides and algaecides to hand-harvesting, benthic barriers, mechanical harvesting and hydroraking. And Stevenson needs every single one of these tools to stay ahead of the problematic weeds.
“These plants are very good at what they do, in terms of taking advantage of their new predator-free homes,” he said. “With curly-leaf pondweed, it starts growing in the fall before the water even freezes, and then when the ice breaks, it shoots up many centimeters per day. The native plants don’t have this kind of strategy and can’t compete with it.”
Milfoil is similarly devious. Pulling this plant apart will actually help it.
“Eurasian water milfoil is found in many Adirondack Lakes, and each year it spreads to a few more,” Tobiessen writes in his book, The Secret Life of a Lake. “When it becomes established, water milfoil spreads from fragmentation of stem tips, which float with the wind and then sink to the sediment to establish new populations. Fragmentation can occur spontaneously, or it can be the result of motorboat propellers or wave action.”
Garlic mustard also utilizes some colonization tricks.
“Garlic mustard lives for two years before flowering, setting seeds and dying,” Corbin said. “The manual control strategy used by The Nature Conservancy concentrates on pulling flowering plants in the hopes that the next generation of seeds never forms.”
“This is important because each plant can produce hundreds of seeds, which can live in the soil for over a decade before germinating,” he continued. “Your removal process can fail if you miss even a few plants; and because these seeds can survive so long, new plants will pop up each spring for a long time.”
These talents are partly what make invasive species so difficult – and pricey – to control.
"What people sometimes don’t understand is that it takes decades for lakes to change, so undoing damage done by invasive species can take years,” Stevenson said. “Even then, because of reproductive patterns or humans’ inability to find every individual, you’re often only at the point where the invasions can be kept in check with annual management.
“And that’s expensive. For a small pond it can cost a few thousand dollars for annual management, up to millions for large water bodies.”
Take Loon Lake in Chestertown, N.Y. (southeastern Adirondacks): Lycott Environmental has been working to manage Eurasian water milfoil here for about five years.
The majority of this time, Stevenson said, his divers have been hand-harvesting the weed in hopes of getting rid of it. This year, they’ll be targeting milfoil with a granular herbicide as well.
This integrated approach for this small lake, he added, costs $60,000 to $100,000 a year.
At Lake George, management of the Asian clam has meant the expenditure of $1.5 million for just two years of treatment with underwater mats and suctioning, according to a 2012 Albany Times Union article.
Bills like these, sometimes offset by grants or similar funds, are often paid by lake associations and other local organizations, as is the case with Lake George.
Such expenditures are unlikely to end, unless the pests stop turning up. But preventing an invasion before it starts might be even harder than controlling one that’s underway.
How they invade
Today, interstate or international travel is as easy as hopping in your car or boarding a boat or plane. When you come back, if you’re a large company, you never know what’s hiding out in that timber you’re importing to the U.S. Even if you’re a tourist, you never know what’s tagging along on your car wheels or outboard motor.
Recreational boaters, for instance, likely transported the Asian clam to Lake George in bilge water or bait wells contaminated during visits to infested locations elsewhere. Other invasive species have probably taken similar roads.
“New York is a major point of entry for passengers, cargo and mail entering the United States. New York is served by 13 airports, 6 shipping ports and 800 miles of interstate canal systems,” the N.Y.S. Invasive Species Task Force reported in 2005. “Three dozen freight railroads haul 16 percent of the nation’s cross-border trade.”
Monitoring all these pathways, their goods and vehicles is a gargantuan task. It’s simply impossible to inspect every bit of cargo, or every vacationer’s boat entering an Adirondack lake from the Erie or Champlain canals. It’s equally impossible to keep people from buying pretty, perfectly legal, invasive plants from nurseries.
Eurasian water milfoil, purple loosestrife and curly-leaf pondweed (from Eurasia too) were originally brought to the U.S. for landscaping or as vegetation for fish tanks.
“The beautiful, feathery leaves of milfoil made it an attractive aquarium plant, and we assume that some people grew tired of tending their aquaria and emptied them into a local waterway,” Tobiessen writes in his book. “Curly-leaf pondweed was introduced the same way.”
The infamous purple loosestrife, now common in the Adirondacks, came as an ornamental. Its robust root system and incredible reproductive capacity – a single plant produces up to 2.5 million, long-lived seeds – allow it to dominate wetlands.
“Gardeners can purchase loosestrife from seed catalogs even though the plant is designated as a problematic invasive in most states, including New York,” Tobiessen writes. “Some are sold as sterile hybrids, but such claims have been shown to be false.”
Despite such challenges, people are not twiddling their thumbs while invasive species continue their colonization.
Fighting the usurpers
In the war against living pollution, victory may be improbable much of the time, but it isn’t always impossible.
In March, The New York Times reported that New Jersey declared the Asian longhorned beetle eradicated – more than 20,000 infected hardwood trees were felled and insecticides were used. Two months later, Manhattan and Staten Island also completed successful campaigns against the insect. While parts of Brooklyn, Queens and Long Island are still dealing with the pest, it’s a start.
A start, though, is something Tobiessen doesn’t want other interlopers to get.
A long-time summer resident of the Adirondacks, he owns a home on Sacandaga Lake near Speculator, N.Y. And he wants to keep Sacandaga the way it is – free of the nastiest invaders, like milfoil.
“In 2009, our lake association and the town of Lake Pleasant passed the first law in New York State targeting all aquatic invasive species,” he said. “The local statute prohibits the transport of aquatic weeds into our lake. We have only a few boat ramps, so we pay someone to stand there and inspect people’s watercraft before they enter the lake.”
“It’s a law that’s written broadly to offer wide protection,” he added. “Boats are not allowed to be put into our lakes if they have vegetation of any kind on them.”
Additional action is being taken at the local level by other organizations performing direct management of invasive species and/or developing partnerships with other groups to educate the public. According to an April article in the Schenectady Daily Gazette, for instance, the Lake George Park Commission is pushing for mandatory boat inspections.
New York State itself is officially beginning to take a stand as well.
In June 2012, Gov. Andrew Cuomo signed the Invasive Species Prevention Act into law. It requires the state departments of Environmental Conservation and Agriculture and Markets to develop regulations for the sale, purchase, possession, introduction, importation and transport of invasive species. In addition, the agencies have to create a list of prohibited species that are unlawful to possess with the intent to sell or release into the wild.
Corbin’s own work with The Nature Conservancy, to create cost-benefit models relating to invasive species management, could be beneficial in future regulatory decisions.
“The exciting thing about this project is that it may really help guide public policy by helping justify invasive species management on an economic basis that, so far, has mostly been justified on a biological basis,” he said.
Stevenson and Lycott Environmental, with their hand-harvesting and other management services, also offer useful tools to individuals, businesses and organizations interested in putting these usurpers in their place.
And it’s something Stevenson, who majored in civil engineering at Union, is only too happy to do.
“We’re really working to keep precious resources open and usable for future generations,” he said. “We could turn our backs and let these difficult problems just keep growing and say, ‘There’s nothing we can do.’”
“But that’s not a sustainable or responsible approach,” Stevenson added. “We have to do this; we’re not getting more of these resources.”
And in the Adirondacks at least, it’s not too late to protect many of them from infestation.
Of the 319 lakes surveyed as of 2012 by the Adirondack Park Invasive Plant Program, Tobiessen said, only 88 were found to contain invasive species.
To maintain this, though, everyone – not just scientists – has to be aware of the problem.
Best defense: good offense
“Really, the most effective way to manage invasive species is to not get them in the first place,” Stevenson said. “We constantly tell lake associations to be on the lookout for things they don’t have, because if you can keep something from coming in, that’ll really be a win.”
And that’s why knowledge is power, especially in the hands of typical people enjoying lakes, woodlands or any other environment.
“There are some very active groups in the Adirondacks raising awareness of invasive species, like the Lake George Association and Adirondack Park Invasive Plant Program,” Tobiessen said. “A more knowledgeable public, that can identify milfoil or Asian clams, will be a big help. The more we educate lake users, the better our chances of controlling invasive species will be.”
And knowledge is really why he wrote The Secret Life of Lakes in the first place. A comprehensive overview of all things aquatic, from water chemistry to nutrient enrichment to acid rain and invasive species, the book is designed for the non-scientist.
“Ultimately, my purpose was to help the curious lake enthusiast better understand the dynamics within these complex ecosystems,” Tobiessen writes in the prologue. “The more we understand these beautiful ecosystems, the deeper appreciation we will have for our lakes, and the wiser our decisions will be in preserving them.”