Wildlife Center Classroom Series · 2017-06-14 · Wildlife Center Classroom Series Invasive Species 101 Wednesday June 14, 2017 Alex Wehrung, WCV: Welcome to this month’s Wildlife

Wildlife Center Classroom Series Invasive Species 101

Wednesday June 14, 2017

Alex Wehrung, WCV:

Welcome to this month’s Wildlife Center Classroom Series: Invasive Species 101!

Alex Wehrung, WCV:

If this is your first time watching the Critter Cams or being a part of the moderated discussion, let us

know in the comments – let’s jump right in!

Comment From Jen

First time for both!

Alex Wehrung, WCV:

Great to have you with us, Jen!

Alex Wehrung, WCV:

Invasive species have become a better-known environmental issue during the past few decades, and

with good reason. The National Wildlife Federation (NWF) estimates that approximately 42% of

Threatened or Endangered species at risk primarily due to invasive species.

Alex Wehrung, WCV:

Yikes! To understand exactly what we’re dealing with here, we need to first define what an invasive

species actually is; however, the definition itself presents a bit of a gray area.

Comment From ʕ•ᴥ́•ʔ̀ dancelady ʕ•ᴥ́•ʔ̀

Starlings? I used to get these in my house all the time through the fireplace. Trying to catch them was a

scene, really difficult to get.

Alex Wehrung, WCV:

Yep -- that's a classic example. We'll talk about European Starlings later on!

Alex Wehrung, WCV:

Some biologist question whether a native species can be considered invasive, so there are two slightly

differing definitions.

Alex Wehrung, WCV:

The first – and most widely accepted – applies to non-indigenous (or “non-native”) species:

Alex Wehrung, WCV:

“An invasive species can be any kind of living organism (to include vertebrates, invertebrates, plants,

fungus, bacteria – even an organism’s seeds or eggs) that is not native to an ecosystem and which

causes harm.” –NWF

Alex Wehrung, WCV:

The second definition includes the first, but broadens the boundaries to include indigenous (or “native”)

species along side the non-native ones. Deer, for example, are native to the United States, but are

overpopulating their native zones and spreading into areas where populations haven’t been observed in

the past.

Alex Wehrung, WCV:

The exact type of “harm” an invasive species can cause is quite varied. They can harm native animals,

the environment, the economy, and even human health. We’ll explore some specific examples a little

later on in the discussion.

Alex Wehrung, WCV:

This map created by The Wildlife Society highlights areas that have become (or already are) most-

threatened by invasive species:

Comment From Jen

WOW!

Alex Wehrung, WCV:

While there are a huge variety of living organisms with the “invasive” label, they all share four key traits.

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1. They grow and reproduce quickly

2. They spread aggressively

3. They tend to prey on native species

4. They benefit from an absence of natural predators in new areas

Alex Wehrung, WCV:

In short, they alter the way an ecosystem works in a negative way.

Alex Wehrung, WCV:

It’s also important to remember that an invasive species doesn’t have to come from another country!

Alex Wehrung, WCV:

A good example is Lake Trout native to the Great Lakes. They’re all-American, but are considered

invasive in Yellowstone Lake in Wyoming because they outcompete the native Cutthroat Trout for

resources like food, space, and shelter.

Alex Wehrung, WCV:

When a new and aggressive species is introduced, they immediately bring with them both direct and

indirect threats to an established ecosystem.

Alex Wehrung, WCV:

Direct threats include things like preying on native species, out-competing native species, causing or

carrying diseases, and even preventing native species from reproducing or killing their young.

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Indirect threats are a little less obvious at first glance, but are just as important.

Alex Wehrung, WCV:

They include things like changing the overall structure of the food web, decreasing biodiversity, altering

ecosystem conditions (like the chemistry of the soil, or intensity and frequency of wildfires), and

damaging infrastructure (like artificial waterways and pipelines, roadways, etc.).

Alex Wehrung, WCV:

It’s estimated that invasive species cost the U.S. $138 BILLION dollars a year to control and manage.

Comment From BarbG

WOW lots of money

Alex Wehrung, WCV:

Yep, you read that correctly -- billion with a "B".

Alex Wehrung, WCV:

So, how do invasive species "invade" an area in the first place? Unfortunately, they primarily spread by

human activities, often (but not always) unintentionally.

Alex Wehrung, WCV:

Let’s take a look at three different invasive species, how they’ve been spread, and the impacts of their

introduction to new ecosystems.

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Case study: The Quagga Mussel, Dreissena bugensis

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Not a very intimidating looking animal, is it?

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Looks can be deceiving – Quagga Mussels, and the closely related Zebra Mussel, have become one of

the most destructive invasive species in recent history.

Comment From Cathy in Nevada

Is that aka zebra mussle?

Alex Wehrung, WCV:

Different species, but very similar in appearance and life cycles.

Comment From BarbG

Living in Michigan, we hear a lot about these

Alex Wehrung, WCV:

From their native range in Ukraine, the free-floating larval form of these mussels were unknowingly

transported across the Atlantic Ocean in the ballast tanks of large ships.

Alex Wehrung, WCV:

A ballast is a compartment in large ships that hold water in order to stabilize it in rough seas. Ballast

water is drawn in at port before departure, and purged upon arrival.

Alex Wehrung, WCV:

After being dumped out of the ballast tanks of cargo ships arriving from Europe into the Great Lakes in

the late 1980’s, they have spread dramatically in the same way – being transported in the hulls of ships

and recreational boats. This USGS map shows known locations of both these mussels in 2015:

Comment From Guest

what about cats? can they be considered an invasive species? (outdoor cats, that is)

Alex Wehrung, WCV:

Yes, feral cats are considered to be an invasive species!


Have they learned to "poison" the water before emptying the tanks?

Alex Wehrung, WCV:

Unfortunately, poisoning ballast water would harm all the wildlife and ecosystem factors in bodies of

water where it would be purged, and hasn't been considered as a management tactic.

Alex Wehrung, WCV:

Quagga Mussels (and Zebra Mussels) can attach to almost any hard surface -- they clog water intake and

discharge pipes, attach themselves to boat hulls and docks, and they even attach to native mussels and

crayfish.

Alex Wehrung, WCV:

That used to be a shoe!

Comment From Jen

WHOA!


Thought something like changing salinity to kill invasive species, then resalinize it before emptying tanks

Alex Wehrung, WCV:

Oh, I see! I didn't come across any idea like that when I was researching for this class, but it's an

interesting idea...as a fresh water species, they would certainly be affected by salt water...interesting!

Comment From Deb in PA

Hello Alex! Our biggest problem in this area is House Sparrows. They go into Bluebird Houses and kill the

adult and babies. It's so frustrating...

Alex Wehrung, WCV:

Yep, another invasive bird species that outcompetes the natives.

Alex Wehrung, WCV:

Not only do Quagga Mussels out-compete native species for space, they reproduce at an explosive rate.

As filter feeders, they strain algae and plankton from the water – high populations of the mussels can

transform bodies of water into an ecological “dead-zone”.

Alex Wehrung, WCV:

With few natural predators – and the ability to close their shells and pass through digestive systems

unharmed – these mussels are almost impossible to remove once they’ve infested an area.

Alex Wehrung, WCV:

The best method of removal is prevention!

Alex Wehrung, WCV:

Ways to prevent accidentally transporting them are simple and inexpensive: washing and completely

drying boats and other equipment, removing any aquatic plants or mud, and throwing away unwanted

fishing bait in the trash.

Comment From Melinda in NC

I saw a study on Lionfish once. Never thought about how invasive they are.

Alex Wehrung, WCV:

Invasives come in all shapes and sizes, it's true.

Alex Wehrung, WCV: On to the next case study!

Alex Wehrung, WCV:

Case study: Emerald Ash Borer, Agrilus planipennis

Comment From Lynda in AZ

In regards to the mussel problem, there is a radio ad that basically says "Don't move a mussel" where

they remind boaters to be careful with their boats (with the Colorado River right here, boating and PWC

are BIG!)

Alex Wehrung, WCV: (Fun fact: I used to work as an Aquatic Nuisance Species Park Ranger in Colorado,

our motto was "Spread the message, not the mussles.")

Alex Wehrung, WCV:

The Emerald Ash Borer (EAB), originally from eastern Russia, northern China, Japan, and Korea, is an

insect that had never been observed in North America before June of 2002.

Alex Wehrung, WCV:

While biologists aren’t exactly sure how they got to America, it’s most likely that they came in ash wood

used for packing and shipping pallets and containers.

Alex Wehrung, WCV:

In 2002, the EAB was initially found in six counties in southeastern Michigan. Today, the EAB has spread

to almost all of the East Coast and Midwest, including several Canadian provinces:

Comment From BarbG

another big problem in Michigan

Alex Wehrung, WCV:

Yep -- seeing a theme? Lots of shipping ports and global trade routes near water ways...

Comment From Jen

We are losing so many trees to this one!

Alex Wehrung, WCV:

When this insect burrows beneath the bark of an ash tree to lay it’s eggs, the newly-hatched larvae eat

and destroy water and nutrient conducting tissues -- effectively killing an otherwise healthy tree in as

little as one year.

Comment From BarbG

lots of trees affected

Alex Wehrung, WCV

Alex Wehrung, WCV:

Like the Quagga Mussel, though, this insect is the most-widely spread by people!

Alex Wehrung, WCV:

EAB’s usually only fly within a mile from the tree they initially emerged from. However, when people

move infested trees to nurseries, or transport infested firewood to new areas, they can spread very

quickly.

Comment From CarolinaGirl

Been lurking and learning. There must be a huge list of invasive, animals and plants. With world travel

what it is today, that list will surely become longer as things hop on for the ride.

Alex Wehrung, WCV:

Hey, CarolinaGirl! You're right -- the list is huge, especially when you include plants.

Alex Wehrung, WCV:

In fact, the EAB is considered to be the most destructive forest pest ever seen in North America. The

solution? Once again, prevention.

Alex Wehrung, WCV:

You’ve probably seen signs like these at campgrounds around the country:

Alex Wehrung, WCV:

Many agencies and universities are working together to educate citizens about the identification of ash

trees and the EAB, and many state and federal agencies have programs in place to help restore the

urban forest in cities that sustained heavy EAB damage.

Comment From BarbG

All campgrounds in Michigan have signs like that too

Alex Wehrung, WCV:

On to our final case study...

Alex Wehrung, WCV:

Case study: The European Starling, Sturnus vulgaris


It seems like a small price to pay if you have a business, just like killing eagles -- should be a much bigger

and more serious penalty?

Alex Wehrung, WCV:

I'm not sure about specific laws for each state, but I know from working with the Colorado Department

of Parks & Wildlife that knowingly transporting invasive species can result in some very large fines, and

even jail time for repeating offenders.

Alex Wehrung, WCV:

The European Starling is a well-known species throughout the birding world, and a very common sight

throughout the U.S. It’s origins as an invasive species are a bit different compared to our previous case

studies, though!

Alex Wehrung, WCV:

TIME magazine explains their history in this 2010 article:

Alex Wehrung, WCV:

“In 1890 New York drug manufacturer Eugene Schieffelin released some 60 European starlings in Central

Park. His dream was to introduce every bird mentioned by Shakespeare into North America — an intent

that proved to be more Hitchcock than Bard.

Alex Wehrung, WCV:

Schieffelin hoped the songbirds would prosper in their new home in ways the skylarks and song thrushes

had not, and they certainly did.”

Alex Wehrung, WCV:

Since 1890, those 60 European Starlings have reproduced and spread from Central Park to the entire

continental U.S.:

Alex Wehrung, WCV:

These birds can roost in flocks of up to one million individuals!

Alex Wehrung, WCV:

Not only do they outcompete native species, they can devour literal tons of crops in a single day, and

their droppings are thought to be vectors of several infectious diseases.

Alex Wehrung, WCV:

Because these birds as so well-stablished and wide-spread, removal is virtually impossible. Various

control methods have been tried such as placing protective netting over crops, poisoning and shooting,

and eliminating nest sites and food and water sources (as invasive species, these birds are not protected

by the Bird Migratory Act).

Alex Wehrung, WCV:

A 2001 Columbia University study proved that a possible long term solution, particularly for reducing

numbers of starlings in areas where they are competing for nest sites with cavity nesters, might be to

provide a large number of nest boxes away from the immediate areas of the cavity nesters, and then

remove eggs or young.


Have you any idea how they can flock massively and swerve so suddenly, all together, nobody in charge,

but still like a practiced flow? I know it is too much to admire, but still kinda amazing.

Alex Wehrung, WCV:

Reminds one of a school of fish, doesn't it?

Alex Wehrung, WCV:

While it can be easy to feel like there's no hope of ever truly solving the issue of invasive species, it’s

not all doom and gloom!

Alex Wehrung, WCV:

The solutions to help curb the spread of invasive species are inexpensive, easy to do, and well within the

average person’s capabilities.

Comment From PaulaR

there are some good scientific studies now on "murmurations" of starlings...they watch each other,

paying most attention to the bird on each side of them rather than ahead or behind...

Alex Wehrung, WCV:

Plant native plants and remove any invasive plants in your garden or yard. There are a huge number of

native alternatives to common exotic ornamentals, and our local pollinators will thank you.

Alex Wehrung, WCV:

Learn to identify invasive species in your areas. Report any sightings to local natural resource

management agencies!

Alex Wehrung, WCV:

Regularly clean gear like boots, tires, or any equipment you use outdoors.

Alex Wehrung, WCV:

When camping, only use or buy firewood from within 30 miles of your campsite.


Like helping the eagles, EDUCATION!

Alex Wehrung, WCV:

Exactly!

Alex Wehrung, WCV:

Help spread message and knowledge about invasive species to friends and family.

Alex Wehrung, WCV:

For anyone interesting in learning more about what species might be considered invasive in your area, I

highly recommend checking out the US Department of Agriculture’s online National Agricultural Library

page:

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https://www.invasivespeciesinfo.gov/unitedstates/state.shtml

Alex Wehrung, WCV:

Just click on your state, and a number of educational resources are available. It's a great tool for

learning!

Alex Wehrung, WCV:

That’s all for the Classroom Session today, everyone, thanks for joining in on the discussion! I’ll be online

for a few more minutes to answer any questions before logging off. Have a great day!

Wildlife Center Classroom Series · 2017-06-14 · Wildlife Center Classroom Series Invasive Species 101 Wednesday June 14, 2017 Alex Wehrung, WCV: Welcome to this month’s Wildlife

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