non-native - The Environment Report

Weevils vs. The Mile-A-Minute Weed

The mile-a-minute weed (Photo courtesy of the USDA)

Sometimes biologists fight foreign
pests with other foreign animals. But that
can be risky because it can create a bigger
problem than the one it’s supposed to solve.
Sabri Ben-Achour reports on one of the latest attempts to stop a weedy pest:

Transcript

On farms, backyards, and rights of way up the Eastern Seaboard a pointy leaved thorny
newcomer is becoming increasingly visible. It’s called mile-a-minute weed.

Bob Trumbule is an entomologist. He leads me through a stream valley north of
Washington DC where blackberries and small trees are being swallowed up by this
invasive vine.

“So now we’re getting into the mile-a-minute here. Basically what it does it, it’s an
annual vine, it grows up and over plants, it smothers them, out competes them for
sunlight, and weighs them down.”

The weed is native to Eastern Asia: China and Japan. It was introduced accidentally in
Pennsylvania in the thirties. From there, it’s spread to seven other states. It prevents new
trees from sprouting in forests. But back in Asia, it’s not a dominating species like it is
here.

Judith Hough-Goldstein is a professor at the University of Delaware.

“Part of the reason is because it doesn’t have anything that’s feeding on it. It’s gonna be
without its predators so it can out-compete other plants.”

Over several years, biologists searched for something that would eat the vine. They
found a tiny, black weevil in China. It feeds on the plant and lays it’s eggs there, keeping
things in check – in Asia.

“Here are the weevils. I’m gonna give you a glimpse of them here in the cup. They look
almost like little ticks. I’m gonna put them down here in the mile a minute weed patch,
and basically what they’ll do – they’re tough little guys – they’ll climb around and in the
past experience have started to feed almost immediately.”

Up close, they look like little anteaters, poking around the leaves with long snouts.

This may sound risky. There are lots of examples where similar approaches have gone
wrong. A parasite was introduced in North America to control gypsymoths. It attacked
native silkmoths. Mississippi catfish farmers used Asian carp to control algae. They got
loose and are taking over the Mississippi River system and threatening the Great Lakes.

And Trumbule admits nobody knows for sure exactly what might happen.

“Any scientist that might say otherwise is not being honest with themselves or the person
asking the question.”

But he says a lot’s been learned since the days when any scientist could introduce a
species on a whim. These days, exhaustive testing and federal permits are required
before anything is released.

That’s why for almost ten years Judith Hough-Goldstein has been trying to determine if
the weevil would eat anything else. Tests were conducted in a U.S. Department of
Agriculture ‘quarantine facility’ with sealed windows and its own re-circulated air supply.

“So what we found was that, in fact, this particular weevil is extremely host specific. The
insect has evolved to depend on the plant.”

So much so that the weevils and larvae actually starved to death rather than feed on other
plants.

In field tests in New Jersey and Delaware, the weevils have decimated mile-a-minute
weed. Some researchers say it’s the most impressive biocontrol they’ve worked with.

For The Environment Report, I’m Sabri Ben-Achour.

Westward Ho for the Ash Borer

Adult emerald ash borer (Photo by David Cappaert, Michigan State University, courtesy of the Michigan Department of Agriculture)

The emerald ash borer has eaten through
millions of trees in the US and is spreading
west. Erin Toner has more:

Transcript

The emerald ash borer has eaten through
millions of trees in the US and is spreading
west. Erin Toner has more:

For six long years, the tiny metallic-green emerald ash borer has been a killing machine,
starting with millions of ash trees in Michigan and Canada, and then munching its way
into 10 states.

It was recently discovered in Missouri, and now, it’s in Wisconsin.

The prognosis is not good.

Darrell Zastrow is with the Wisconsin Department of Natural Resources.

“Our forests are not typically resilient against non-native species and that is true for
the emerald ash borer. It is generally considered to be a poster child for invasive
species.”

Officials in Wisconsin are doing what everyone else has done – restricting the movement
of firewood and telling people how to protect their trees.

Some promising treatments to fight the emerald ash borer are being tested, but so far,
nothing has worked at keeping the insect from spreading west.

For The Environment Report, I’m Erin Toner.

Swan Song of the Mute Swans

Wildlife officials want to eliminate the European mute swan so it doesn't compete with native birds. (Photo by Christina Shockley)

Controversy over what to do about a non-native swan has taken an
unusual turn. One state that was going to kill all of its mute swans
will now give some of them a short lease on life. It’s going to let
people “adopt” the wild birds. Christina Shockley has the story:

Transcript

Mute swans are large, gorgeous, white birds. They were brought to the
U.S. from Europe in the 1800s to beautify parks and estates. The swans
were meant to be kept in captivity, but they escaped, and since, the
numbers have skyrocketed along the Great Lakes and Eastern seaboard.

So, like in other areas, the Wisconsin Department of Natural Resources
has come up with a plan. The state wants to shoot all the mute swans,
but this doesn’t sit well with a lot of people.

Pat Kujawa is one of them. Kujawa is sitting in her home on Phantom
Lake. The area is home to about 85% of Wisconsin’s mute swans. Each
summer for several years, Kujawa’s family has bonded with the mute
swans. She sees the birds as neighbors on the lake.

She holds a photo album full of pictures of the swans and her kids as
they grew up:

“We have pictures of our son Kyle swimming with them, and he’s probably
about I would say 8 or 9 years old, and again other pictures like that,
showing the parents standing back, and all of the babies coming up and
taking bread right out of Kyle’s hands. Sort of suggests that perhaps
the DNR characterization of them being aggressive is somewhat
misguided, or at least it’s what they want people to hear.”

Wildlife officials say the mute swans ARE aggressive, especially during
the nesting and breeding season. They say the mutes push native birds
out of their habitat and upset aquatic life by uprooting vegetation
along the shore.

Officials also say the mute swan was posing a problem as the state
worked to re-introduce the native trumpeter swan. Their numbers have
just recovered.

But because of protests from people like Kujawa, the state government
says it will temporarily modify its mute swan eradication plan. What
they’re doing might seem a little unusual. The state is going to let
people in three counties “adopt,” or sponsor, as many mute swans as they
want.

Erin Celello is from the Department of Natural Resources. She says
people won’t have to bring the birds in the house to live like a cat or
dog, but she says they will have to get the swans fixed:

“They will be able to apply for a permit, to capture a swan from the
wild, and they will be required to neuter that swan, and re-release
that swan into the wild.”

Celello says that will keep the birds from breeding, and the state
won’t shoot the birds when they see them:

“We felt that this is kind of a win-win for everyone. As an agency, we
are still upholding our share of what has become a national mute swan
control policy, while at the same time, allowing for citizens who have
formed emotional attachments to these birds, to keep those birds
around, and keep them on their landscape.”

Celello says the state’s goal is still to kill all of the mute swans. She
says officials will shoot the mutes that aren’t wearing neck tags that
show the birds have been spayed or neutered. And obviously the swans
that have the surgery won’t be having babies. One vet says the spaying
or neutering procedure could cost between 150 and 250 dollars per bird,
and Grace Graham says that might be difficult for her to afford.
Graham is Pat Kujawa’s neighbor on Phantom Lake.

The 70-year-old retired school teacher has been swimming with, and
feeding, the mute swans for years. She says the mute swans should just
be left alone and that it’s wrong to eliminate a species. But she
knows, ultimately, if it’s impossible for the birds to reproduce, the
swans will be gone at some point:

“I don’t want to even think about our lake not having any mute swans on
it. All this summer, the last time I swam with them before the water
got cold I thought, Grace, this is the last time you’re going to get to
do this. Last time you fed them, last time you do all of these things.
It’s kind of like a death thing.”

For the Environment Report, I’m Christina Shockley.

Ten Threats: Natives Bite Back

A big female Lake Erie water snake and a territorial male goby. Snake researcher Dr. Rich King caught the snake out of the lake with the goby in its mouth... the snake was swimming toward shore to enjoy its meal. (Photo by Rebecca Williams)
A recently barfed goby in the plastic bag on the right. Snake biologists barf snakes to see what they're eating... and sometimes, the snakes regurgitate meals voluntarily when you pick them up. (Photo by Rebecca Williams)
Occupational hazards for water snake biologists include: possibly twisting an ankle when leaping over rocks and giant tires, three-foot-tall poison ivy, mosquitoes, sunburn, heatstroke... and oh, yeah - snakebites. Here, Rich King makes a flying leap to catch a big snake with a goby in its mouth, out of the lake. (Photo by Rebecca Williams)

These ten threats to the Great Lakes are complicated. Researchers are finding new ways that nature reacts to them. For example, alien invasive species often compete for food and crowd out the native species. Once a foreign species takes control in an area, there’s not much anyone can do to get rid of them. But occasionally, a native species will bite back. The Great Lakes Radio Consortium’s Rebecca Williams has that story:

Transcript

Invasive species have been a real problem for native species in the Great Lakes, but some native species are turning tails on the invaders. The Great Lakes Radio Consortium’s Lester Graham is our guide in exploring the series Ten Threats to the Great Lakes:

(waves)

These islands in Lake Erie seem like floating Gardens of Eden. They’re
popular with tourists. These islands also really appeal to a rare
snake.

“So there’s a dozen or so of them heading out into the water.”

Meet the Lake Erie water snake. It can grow up to four feet long. Snake expert
Rich King and I are watching a bunch of them swimming away, gray heads
peeking up like periscopes.

These snakes like the lake. They like hanging out in huge piles on docks
and boats, and Rich King’s discovered the snakes love to eat round gobies.

Gobies are invasive fish that are thought to have hitched a ride in the
ballast water of ocean-going ships from foreign ports. The gobies eat the
eggs of native fish such as smallmouth bass, and compete with other fish for
food and nest sites. As gobies have taken over the lake bottom, the native
fish the snakes used to eat are getting harder to find.

“What we’re seeing is that the gobies are apparently a very abundant food
source for the water snakes. Compared to the 1980’s and early 90’s when the
snakes were feeding exclusively on native fish or mudpuppies – the snakes
are now consuming over ninety percent of their prey items are round gobies.”

(Sound of walking over rocks and zebra mussels)

Today, Rich King and his students from Northern Illinois University are
prowling the beaches for snakes. They carry their catches in faded
pillowcases tied to their belt loops. This is the annual snake survey,
Nerodio. That’s Nerodia, the snake’s scientific name, and rodeo, as in
cowboy roundup.

The snake biologists don’t just look under rocks. They dive into the lake
for snakes. They sneak up on piles of snakes and then grab the whole
writhing mass.

The snakes bite. The researchers’ arms are covered in snakebites. The bites aren’t life threatening, but they’re really, really bloody. And then it comes to the job at hand. The biologists are going to force the snakes’ stomach contents out. They call it “barfing the snakes.”

“Some snakes are easier to puke versus others. The water snakes, for
example, they sometimes voluntarily just, bleagh, just puke it out when you
pick them up.”

PhD student Kristin Stanford promises me it’ll be a good show, and we’re in
luck: just down the road, Rich King makes his first prize catch of the day.

“I got a snake with a goby in it. See the bulge: that’s the head end of
the goby. I’m virtually sure it’s a goby. (laughs) So you just very gently work it
forward, and drop it into our ziplock bag. That’s a round
goby.”

King says the snakes are growing faster and getting fatter on their goby
diet. Bigger snakes are less vulnerable to predators, and bigger females
can have more babies.

The researchers are pretty happy about that. That’s because the water snakes
are listed as threatened under the Endangered Species Act. This is the
only place in the world these snakes are found. For years, people were
shooting snakes and bashing them with rocks. Their numbers were getting
dangerously low.

The snake biologists say they understand that a lot of people hate and fear
snakes, but they say now that the snakes are eating gobies, they’re
starting to get a little more popular, especially with fishermen.

(Sound of fisherman casting a spinning rod)

Mark Green fishes for smallmouth bass. Green says it seems like when he
sees more snakes, he has better luck.

“If they’re eating the gobies, that is a good thing. I mean, I’m sure they have their
place… just not at my place.” (laughs)

Green didn’t realize until today that the snakes like to hang out under the
metal rim of the pier, right by his feet. He cringes, but his curiosity
gets the better of him, and he peeks inside one of the pillowcases bulging
with snakes.

GREEN: “When they get ahold of you, do they let go pretty quick, or do they…”

STANFORD: “Typically, but every now and then you get what
I call a “chewer,” and they’ll just sit there and errr-errr-errrng.”

The people and snakes are starting to arrive at an uneasy truce, and the
snakes seem to be well on their way to recovery from all the feasting on
gobies.

The researchers are hoping to learn just how big a bite the snakes can take
out of the goby population, and if, in the long run, it’s good or bad for
water snakes to depend on a foreign fish.

For the GLRC, I’m Rebecca Williams.

Ten Threats: Predicting New Invaders

Some say it's only a matter of time before the Asian Carp enters the Great Lakes. (Photo courtesy of the USFWS)

More than 160 kinds of foreign creatures are in the Great Lakes right now, and every few months, a new one finds its way into the Lakes. Those invasive species are considered the number one problem by the experts we surveyed. The outsiders crowd out native species and disrupt the natural food chain, and it’s likely more will be coming. Zach Peterson reports scientists are putting a lot of time and effort into figuring out which new foreign creatures might next invade the Great Lakes:

Transcript

There are new problems for the Great Lakes on the horizon. The Great Lakes Radio Consortium’s Lester Graham is our guide in a series that explains that new invasive species are one of the Ten
Threats to the Great Lakes:

(Sound of boat motor)

Jim Barta is a charter boat captain just above Lake Erie on the Detroit River. He says over the last decade, zebra mussels and other foreign species have altered the habitat of the walleye he fishes for.

Water that once had a brownish hue is now clear. That’s because Zebra mussels have eaten the algae and plankton that used to cloud the water, and that means Barta’s boat is no longer invisible to the fish he aims to hook.

“You could catch the fish a little closer to the boat because they weren’t as spooked by the boat. They weren’t as afraid of what was taking place.”

So Barta had to rethink his tactics. He now casts his lines out further, and he’s changed lures to continue catching walleye.

But there are other problems the zebra mussel is causing. Eating all the plankton means it’s stealing food at the bottom of the food chain. And, that affects how many fish survive and how much the surviving fish are able to grow.

Anthony Ricciardi is trying to help Barta, and other people who rely on a stable Great Lakes ecosystem. He’s an “invasion biologist” at McGill University in Montreal.

Ricciardi looks for evidence that can predict the next non-native species that might make it’s way into the Great Lakes. He says species that have spread throughout waterways in Europe and Asia are prime candidates to become Great Lakes invaders.

“If the organism has shown itself to be invasive elsewhere, it has the ability to adapt to new habitats, to rapidly increase in small numbers, to dominate ecosystems, or to change them in certain ways that change the rules of exsistence for everything else, and thus can cause a disruption.”

Ricciardi says most aquatic invasive species are transported to North America in the ballast tanks of ocean freighters. Freighters use ballast water to help balance their loads. Some of the foreign species hitchhike in the ballast water or in the sediment in the bottom of the ballasts.

Ships coming from overseas release those foreign species unintentionally when they pump out ballast water in Great Lakes ports. Ricciardi says one of the potential invaders that might pose the next big threat to the Great Lakes is the “killer shrimp.” Like the Zebra Mussel, it’s a native of the Black Sea.

“And it’s earned the name killer shrimp because it attacks invertebrates, all kinds of invertebrates, including some that are bigger than it is. And it takes bites out of them and kills them, but doesn’t necessarily eat them. So, it’s not immediately satiated. It actually feeds in a buffet style: it’ll sample invertebrates, and so it can leave a lot of carcasses around it.”

Ballasts on cargo ships aren’t the only way foreign species can get into the Lakes. Right now, scientists are watching as a giant Asian Carp makes its way toward Lake Michigan. It’s a voracious eater and it grows to a hundred pounds or more.

This non-native fish was introduced into the Mississippi River, when flooding allowed the carp to escape from fish farms in the South. A manmade canal near Chicago connects the Mississippi River system to the Great Lakes.

If it gets past an electric barrier in the canal, it could invade. Many scientists believe it’s just a matter of time. Another invasive, the sea lamprey, also got into the Great Lakes through a manmade canal.

But, researchers don’t usually know when or where an invader will show up. David Reid is a researcher for the Great Lakes Environmental Research Laboratory in Ann Arbor. He says they can’t predict the effect an invader will have when it arrives in its new ecosystem.

“That’s the problem. We don’t know when the next zebra mussel’s going to come in. We don’t know when the next sea lamprey type of organism is going to come in. Generally, if you look at the invasion history of the Great Lakes, you’re seeing about one new organism being reported probably about once every eight months.”

Knowing what the next invader might be could help biologists, fisheries experts, and fishermen know what to do to limit its spread. Invasional biologists hope that their work will help develop the most effective measures to limit harm to the Great Lakes.

For the GLRC, I’m Zach Peterson.

Researchers Call for Hydrilla Hunt

Great Lakes researchers are looking for volunteers to help search for an invasive aquatic plant that can choke out native vegetation, and make it tough to fish or boat. The Great Lakes Radio Consortium’s Erin Toner reports:

Transcript

Great Lakes researchers are looking for volunteers to help search for an invasive aquatic
plant that can choke out native vegetation, and make it tough to fish or boat. The Great
Lakes Radio Consortium’s Erin Toner reports:

Universities and Sea Grant programs throughout the region want people to search bays
and inland lakes for a non-native plant called hydrilla. It’s been found in waterways in
southern states and on the East Coast. Researchers want to make sure hydrilla doesn’t
gain a foothold in the Great Lakes.

Howard Wandell is an inland lakes specialist at Michigan State University. He says
hydrilla forms a net of vines at the surface of the water.

“It’s difficult to motorboat through and obviously trying to cast fishing lures through it is
very difficult if not impossible. And of course then just the idea of even trying to swim
in it, people are very repulsed by the idea of trying to go out and try to recreate in this
tangled mass of vegetation.”

Wandell says hydrilla also blocks sunlight, which can kill native water plants.

For the GLRC, I’m Erin Toner.

New Gmo Grass to Get Federal Approval?

The quest for a perfectly manIcured lawn has driven some lawn care companies to create a grass resistant to weed killer. Some worry, however, that they've created an invasive species. (Photo by Philipp Pilz)

An environmental watchdog group is hoping to block federal approval of a new genetically modified type of grass. The group says the grass poses a threat to natural areas. The Great Lakes Radio Consortium’s Erin Toner reports:

Transcript

An environmental watchdog group is hoping to block fedral approval of a new genetically
modified type of grass. The group says the grass poses a threat to natural areas. The Great
Lakes Radio Consortium’s Erin Toner reports:

Two companies – Scotts and Monsanto – want the government’s approval to commercialize a type of
creeping bentgrass. The grass would mainly be planted on lawns and golf courses because it’s
resistant to Roundup, a popular weed killer. But critics of the bio-engineered grass say it
needs more testing. For one thing, they say, genes from the grass can spread and strengthen
non-native plants.

Joe Mendelson is with the International Center for Technology Assessment.

“The end result is you’re going to create a grass that is invasive, that will take over natural
areas like our grasslands and or forest areas, and we won’t be able to control it. That’s going
to have a very negative impact on a number of sensitive ecosystems.”

The U.S. Forest Service has also weighed in, saying the grass has the potential to have a
negative effect on all of the country’s grasslands and natural forests. Scotts has said the
bio-engineered grass poses no threat to natural areas.

For the Great Lakes Radio Consortium, I’m Erin Toner.

Gl States Speak Up on Ballast Water Lawsuit

A lawsuit brought by several environmental groups in California seeks to increase protection against invasive species. The groups hope to force the Environmental Protection Agency to regulate ballast water discharge. Now, officials from the eight Great Lakes states are writing-in to support these groups in their lawsuit. The Great Lakes Radio Consortium’s Celeste Headlee reports:

Transcript

A lawsuit brought by several environmental groups in California seeks
to increase protection against invasive species by forcing the
Environmental Protection Agency to regulate ballast water discharge.
Now, officials from the eight Great Lakes states are writing in to
support these groups in their lawsuit. The Great Lakes Radio
Consortium’s Celeste Headlee reports:

Researchers say ballast water from oceangoing ships is one of the
primary methods by which invasive species enter the Great Lakes.
State Attorney General Mike Cox wrote the amicus brief for Michigan.
He says under current EPA rules any ship that claims it doesn’t have
ballast can, in fact, issue discharge into the water.

“Now we know that right now and on any given day, about 85 to 90
percent of these ships claim that they don’t have any ballast on board.
That’s a claim that stretches credulity, quite simply because all ships
need ballast if they don’t have cargo.”

The National Oceanic and Atmospheric Administration estimates that it
costs 45 million dollars a year just to control zebra mussels and sea
lampreys in the Great Lakes. Cox and the seven other Great Lakes
Attorneys General say the EPA must do more to protect the waters from
invasive species. The AGs have filed eight separate amicus briefs
supporting the case against the government. For the Great Lakes Radio
Consortium, I’m Celeste Headlee.

Crackdown on Giant Snails

Snails that can grow up to seven inches long have federal health officials cracking down on schools, pet shops and “pet swap meets” across the Midwest. The Great Lakes Radio Consortium’s Chuck Quirmbach reports:

Transcript

Snails that can grow up to seven inches long have federal
health officials cracking down on schools, pet shops and ‘pet swap meets’
across the Midwest. The Great Lakes Radio Consortium’s Chuck Quirmbach reports:

Giant African Land Snails are a non-native species known to rapidly eat plants and
possibly spread disease. It’s illegal to possess the snails in the U.S. Federal and state
officials have seized more than 1000 of the snails from schools, pet shops and homes
in Wisconsin over the last few months.

Now, the warnings are going out across the region. David Robinson studies mollusks for
the U.S. Department of Agriculture. He says the snails are not likely to survive an upper
Midwest winter. But Robinson doesn’t want the snails getting into warmer states and
their farm fields.

“There is always a possibility of someone taking a snail down south… very often when
people get tired of a pet…and this applies to any kind of pet… very often the temptation is
to release it to the environment.”

So far, government officials are not levying fines against anyone for
possessing the giant snails, contending most people don’t know about
the potential risk.

For the Great Lakes Radio Consortium, I’m Chuck Quirmbach.

Study: Invasive Plants Lack Microbial Controls

Spotted Knapweed seed heads - Land managers work hard to control or prevent invasive plants like this one from taking root. New research may help their efforts. (Photo by Barry Rice/The Nature Conservancy)

New research indicates that some invasive plants spread rapidly because they don’t have natural enemies to keep them in check. The Great Lakes Radio Consortium’s Mark Brush explains:

Transcript

New research indicates that some invasive plants spread rapidly because they
don’t have natural enemies to keep them in check. The Great Lakes Radio
Consortium’s Mark Brush explains:

The research found that some foreign plants thrive in North America because
they’ve escaped their natural enemies. In a study published in the journal
Nature, researchers found some of the enemies the plants escaped were
in the soil. They looked at the invasive plant spotted knapweed. They found the
plants are not only free from microbes that might eat their roots, but they
also found microbes in the areas the plants invaded that actually help them
grow.

Ray Callaway is one of the researchers at the University of Montana.
He says regulations are needed to stop these kinds of invasions:

“I think we ought to have much stronger restrictions on the movement of
horticultural plants and so on from across continents. I think we’re
playing with fire.”

The majority of plant invasions come from the horticultural trade. Policymakers are now
working on a protocol to monitor the importation and sale of non-native plants.

For the Great Lakes Radio Consortium, I’m Mark
Brush.

Tag: non-native

Weevils vs. The Mile-A-Minute Weed

Transcript

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Westward Ho for the Ash Borer

Transcript

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Ten Threats: Natives Bite Back

Transcript

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Ten Threats: Predicting New Invaders

Transcript

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Researchers Call for Hydrilla Hunt

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New Gmo Grass to Get Federal Approval?

Transcript

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Gl States Speak Up on Ballast Water Lawsuit

Transcript

Crackdown on Giant Snails

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Study: Invasive Plants Lack Microbial Controls

Transcript

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