0:00

Places all over the world are suffering from

0:02

a similar ecological problem. The

0:04

specific problems are slightly different everywhere,

0:07

but they're all based on the same fundamental

0:09

issue, invasive species. How

0:12

each invasive species got where they are is

0:14

a different story, but regardless of how they

0:16

got there, some species can wreak havoc

0:18

on an ecosystem once introduced.

0:20

Learn more about invasive species and the

0:23

damage that they've done on this episode of

0:25

Everything Everywhere Daily.

0:30

InsideTracker.com This

0:39

episode is sponsored by InsideTracker. To

0:41

live your healthiest and longest life possible, you

0:44

need to have the appropriate data. InsideTracker

0:47

takes a personalized approach to health and longevity

0:50

by getting data from the most trusted and

0:52

relevant source, your body.

0:54

By using data from your blood, DNA,

0:56

and fitness trackers, InsideTracker

0:59

gives you personalized and science-backed recommendations on

1:02

things you can take control of to optimize

1:04

your health, like food, supplements, workouts,

1:06

and lifestyle choices, including ways to optimize

1:09

sleep and stress.

1:10

InsideTracker tests and provides

1:12

optimal ranges for over 40 biomarkers, like

1:15

APOB, magnesium, vitamin D,

1:17

testosterone, cortisol, and ferritin.

1:20

The thing I love most about InsideTracker is that

1:22

they have a strict, science-backed approach to

1:24

everything that they do.

1:26

For a limited time, you get 20% off the entire InsideTracker

1:28

store when

1:30

you sign up at InsideTracker.com. So

1:35

if you're ready to get a crystal clear picture of what's going

1:37

on inside your body, along with science-backed

1:40

recommendations to optimize what's not working, then

1:42

visit InsideTracker.com.

1:47

This episode is sponsored by the Expedition Unknown

1:50

podcast. Many of you may know

1:52

Josh Gates as the host of the Discovery Channel

1:54

television show Expedition Unknown. The

1:57

Expedition Unknown podcast from Discovery chronicles

2:00

the adventures of Josh Gates as he investigates

2:02

unsolved iconic stories from across the globe.

2:05

With direct audio from the hit TV show of the same

2:07

name, you'll hear Josh explore stories

2:10

like the disappearance of Amelia Earhart in the South

2:12

Pacific and the location of Captain Morgan's

2:14

treasure in Panama.

2:16

These authentic roughshod journeys help

2:18

Josh separate fact from fiction and

2:20

learn the truth behind these compelling stories.

2:23

In one episode, Josh travels to the remote

2:25

and landmine-riddled jungles of Cambodia

2:27

to investigate the lost city of the Khmer

2:29

Empire and search for a mystical relic

2:31

that gave its god-king the power to incinerate

2:34

his enemies.

2:35

In another, Josh travels through Russia and

2:37

Germany looking for stolen objects of great value

2:39

pillaged by the Nazis during World War II.

2:42

In another, he goes to Peru to uncover

2:44

the meaning behind the giant geoglyphs drawn

2:46

into the earth hundreds of years ago. If

2:49

you're a fan of this podcast, you will almost certainly

2:51

love Josh's take on the subjects that he tackles

2:53

around the globe. Listen to Expedition

2:56

Unknown wherever you get your podcasts. Once

2:59

again, that's Expedition Unknown.

3:08

Growing up, I was aware of certain invasive

3:10

species. Where I lived in Wisconsin,

3:12

there were often warnings given to people with boats that

3:14

they had to clean their boats off before they took them out

3:16

of the water to prevent the spread of zebra

3:18

mussels.

3:19

We also had a problem with a species known as the gypsy

3:21

moth, which had spread across the United States

3:23

over the last 150 years. Both

3:26

of these were things that I had heard of in the news, but

3:28

they didn't really have any day-to-day effect

3:30

on me. The thing that really hammered

3:33

home the problem of invasive species was

3:35

my first trip to Australia. In

3:38

addition to the typical passport control you

3:40

have to go through, Australia also

3:42

requires you to go through a very thorough inspection

3:44

of what you're bringing into the country.

3:46

They prevent you from bringing in almost any

3:49

food, especially fruits or vegetables. They

3:51

can ban hiking boots if they aren't clean enough

3:53

and have been recently used. If

3:55

you travel with a cat or a dog, they'll probably

3:58

have to sit in quarantine for up to a month. month,

4:00

and other pets may not be allowed in at all. Having

4:03

gone through the process, I found the biological

4:06

inspection to be more thorough than the process

4:08

of checking my passport.

4:09

When I was done, I was curious as to just

4:12

what the big deal was and why Australia

4:14

was so worried about letting biological material

4:16

into the country.

4:17

It turned out that they had a good

4:20

reason to be concerned. Australia,

4:22

perhaps more than any other country, has suffered

4:25

greatly at the hands of invasive species.

4:28

Before I get into that, I should probably back up

4:30

and explain what invasive species are

4:32

and what exactly the problem is. An

4:34

alien species is any

4:37

species that is not native to a particular region.

4:40

Alien species are not inherently bad. For

4:42

example, almost all agricultural crops

4:44

are alien species.

4:46

An invasive species is an alien

4:48

species that causes great harm to the environment,

4:51

usually because they fill a role in the ecosystem

4:53

where they can outcompete native species or

4:55

because they have no natural predators. So

4:59

wheat is an alien species, but it's not

5:01

an invasive species. We don't have a problem

5:03

with wheat growing everywhere and choking forests

5:06

to death because there's so much wheat being grown.

5:08

In many cases, an alien species

5:10

might be introduced, which is totally unsuited

5:13

for a particular environment, and it quickly dies

5:15

off.

5:15

To propose an extreme example, think

5:18

of what would happen if you put a polar bear in the African

5:20

savanna. As fearsome as

5:22

polar bears are as predators, it's unlikely

5:25

that they will make it in an environment so different

5:27

from the one that they're adapted to.

5:29

The problem of invasive species has

5:31

to do with evolution. Over

5:33

long periods of time, every ecosystem will

5:35

develop an equilibrium of the species that live

5:38

there. All of the plants and animals

5:40

will develop adaptations that will allow them to

5:42

fit and survive, because if they

5:44

can't, they won't be there.

5:46

In the eastern hemisphere, that being

5:48

all of Africa and Eurasia, you

5:51

had massive land masses with countless

5:53

species which made for very robust

5:56

ecosystems.

5:57

However, consider an island in the Pacific Ocean

5:59

like one. of the Hawaiian Islands. Created

6:01

by a volcano, it may have taken thousands

6:04

if not millions of years for the island

6:06

to have been populated with plants and animals.

6:09

Birds would land on it during their migrations,

6:11

bringing with them seeds from their previous location.

6:14

Storms would blow debris onto the island, which

6:16

might bring insects and rarely small

6:18

lizards. Other non-migratory

6:20

species of birds may accidentally be blown

6:22

there during a storm.

6:24

So every so often a new species may appear

6:26

in an ecosystem. What happens will

6:29

result in how that particularly species reacts

6:31

to the ecosystem it now finds itself in.

6:33

While this can occur naturally, it's

6:36

very difficult to do. An

6:37

insect or a bird may be blown across

6:40

a large body of water, but a mammal

6:42

would be near impossible. That's why

6:44

there are no native mammals on any of the Pacific

6:46

islands, save for a species of bat known

6:48

as a flying fox.

6:50

Humans, however, are capable of bringing

6:52

larger animals across long distances, and

6:55

transporting them, either accidentally or

6:57

on purpose, to places they never were

6:59

before.

7:00

Early human seafarers just kept to the shore and

7:03

traveled to places with somewhat similar ecosystems.

7:06

For example, a Chinese trader may go up and down the

7:08

coast of China or Southeast Asia, and any

7:10

species that they brought with them probably

7:12

could have made it there on their own.

7:14

Traders in the Mediterranean were mostly

7:16

trading between ports with similar climates. But

7:19

everything changed when ships started sailing

7:21

across the oceans and began visiting

7:24

the New World and smaller, more remote

7:26

islands.

7:27

Probably the first species which was

7:29

brought across the ocean to be considered invasive

7:32

were rats. Rats

7:34

had plagued sailing ships for centuries. They

7:36

were unwanted passengers that would often feed

7:38

on the food stores of a ship. When

7:40

a ship arrived at an island, it would usually

7:42

anchor off the shore and take a smaller ship to

7:44

land. That prevented most rats from

7:47

leaving the ship. But eventually, ports

7:49

were built, which allowed rats to just walk

7:51

off the ship.

7:52

Some shipwrecks would wash up on shore of

7:55

an island, bringing rats with them. In

7:57

a previous episode on the Rats of South Georgia

7:59

Island, I explained the problem with rats.

8:02

They are omniferous creatures that reproduce rapidly.

8:05

A single pair of breeding rats can result

8:07

in a half a billion rats within just three

8:09

years.

8:10

Rats can devastate the populations

8:13

of almost any animal on an island that has

8:15

no defense, including most reptiles,

8:17

amphibians, and birds.

8:19

They can also consume nuts, making

8:21

it difficult for many plant species to reproduce,

8:24

which is why there are no native trees on

8:26

Easter Island.

8:27

Today, the brown rat, or Norwegian

8:29

rat, can be found on every continent except

8:32

Antarctica, and in almost every urban

8:34

area.

8:34

And oddly enough, despite its name, the

8:37

Norwegian rat is actually believed to have originated

8:39

in Asia.

8:40

The place which has done the best job of eliminating

8:43

rats is the Canadian province of Alberta.

8:46

Alberta is considered to be the world's largest

8:48

rat-free zone today.

8:50

Their efforts began in the 1950s. As

8:52

rats can't survive outside in the winter in Alberta,

8:54

they have to winter inside buildings.

8:57

They've been able to target their efforts, and

8:59

since 2003, they have regularly had

9:01

years with zero rat infestations, which

9:04

is defined as any sighting of two or more

9:06

rats.

9:07

While rats were brought accidentally, many

9:10

invasive species were brought on purpose, often

9:12

for noble intentions.

9:14

In 1859, a man by the name

9:16

of Thomas Austin, who lived in Victoria, Australia,

9:19

released 24 rabbits and let them run around his

9:21

estate. He

9:22

was quoted as saying, The introduction

9:25

of a few rabbits could do little harm and might provide

9:27

a touch of home in addition to a spot of hunting.

9:30

Within 50 years, those 24 rabbits

9:33

had grown to hundreds of millions of

9:35

rabbits and inhabited most of the country. The

9:38

problem with rabbits in Australia

9:40

is that there is really no apex predator in

9:42

Australia to keep their population in check, and

9:45

the fact that rabbits breed,

9:46

like, well, rabbits. The

9:49

rabbits began devastating farms and wiping

9:51

out crops. In 1887,

9:53

the Inter-colonial Rabbit Commission offered

9:55

a 25,000 pound prize to

9:58

anyone who could demonstrate a new and effective way.

9:59

way of exterminating rabbits. It

10:02

eventually led to the creation of the rabbit-proof

10:05

fence in Western Australia, which is one

10:07

of the longest fences in the world.

10:09

Rabbits are far from the only

10:12

invasive species in Australia.

10:14

Another major problem is the cane toad.

10:17

The cane toad is native to Central and South America.

10:20

It was introduced to Australia in 1935 via

10:22

Hawaii with the intent of keeping insect populations

10:25

infecting sugar cane crops in check.

10:27

They pretty much failed at their mission

10:29

of eating the beetles that attack sugar cane, but

10:32

they did spread rapidly. From

10:34

their initial release in Northern Queensland, they

10:36

have been spreading outward ever since and have now reached

10:38

New South Wales and the Northern Territory.

10:41

In addition to simply outcompeting other native

10:43

species, cane toads are poisonous,

10:46

meaning that predators that do eat cane toads

10:48

often die.

10:49

Even camels have become feral in

10:51

the Australian Outback.

10:53

Originally brought to Australia to carry supplies

10:55

through the desert, there are now several hundred

10:57

thousand feral camels that roam the interior

11:00

of the country.

11:01

The impact of camels isn't as bad as

11:03

other species introduced to Australia, but

11:05

it shows that it isn't just small creatures that

11:08

can be invasive.

11:09

The state of Florida suffers from several invasive

11:11

species, and their introduction came in

11:14

a very different way.

11:15

Southern Florida has seen an invasion

11:17

of Burmese pythons,

11:19

giant snakes that can grow up to 18 feet

11:21

or 6 meters long and weigh up to 200 pounds

11:23

or 90 kilograms. How

11:26

did giant snakes get transported from Southeast

11:28

Asia to Florida? The answer is

11:31

exotic pets.

11:32

People get pythons as pet because they think it

11:34

would be cool, but eventually they get too

11:36

big and they can't keep them anymore, so they

11:38

do what they think is the humane thing and

11:41

release them into the wild.

11:42

Once in the wild, they will breed and

11:44

pretty much eat anything and everything. Pythons

11:48

aren't the only problem.

11:49

There is a concern that Nile crocodiles could

11:51

become established in Florida, and these

11:54

are far more deadly than their North American

11:56

counterparts.

11:57

Lionfish have become a huge problem in the core of the world.

11:59

coral reefs off Florida.

12:01

They hail from the Indo-Pacific and were

12:03

shipped as part of the aquarium trade.

12:05

Here too, at some point, someone thought they were

12:07

doing the right thing by letting them free.

12:10

In reality, they are very poisonous and

12:12

have no natural predators.

12:14

Many scuba divers in Florida will now dive

12:16

with a spear gun just to shoot any lionfish

12:19

that they might encounter.

12:20

The Mississippi River and many of its tributaries

12:23

are now suffering from Asian carp. They

12:25

were originally introduced in the 1970s

12:27

to fish farms to keep them clean of algae.

12:30

But after flooding of the Mississippi River, many

12:32

of the fish escaped and established a breeding population.

12:35

They are huge fish that outcompete other

12:38

native fish because they consume so much and

12:40

breed so rapidly. One

12:42

big concern is that they might travel up the Chicago

12:44

Canal, which connects the Mississippi River to

12:46

the Great Lakes. In 1946,

12:49

the Argentine government brought the North American

12:51

Beaver River to Patagonia to create a fur industry.

12:54

The plan backfired dramatically and

12:56

now there are beaver-created dams and flooding areas

12:59

that were never designed to experience flooding.

13:01

They've spread to Chile and are causing problems

13:04

all over Tierra del Fuego National Park. Invasive

13:07

species don't just go from the old world

13:10

to the new, it can go the other way as well.

13:13

The brown tree snake, which is native to Australia,

13:15

was introduced to the island of Guam where it's caused

13:17

huge problems.

13:18

North American raccoons were brought to

13:21

Europe to create a fur industry and then

13:23

later escaped. There are now millions

13:25

of them across the continent.

13:26

In Japan, a popular cartoon by the name

13:29

of Rascal the raccoon resulted in fifteen

13:31

hundred raccoons being imported to Japan for

13:33

people to keep as pets.

13:35

Needles to say, they make horrible pets

13:37

and now they're all over Japan.

13:39

Large-mouthed bass are popular sport fish in North

13:41

America. But they were introduced all

13:44

over the world and now can be found in Africa,

13:46

Europe, New Zealand, Japan, China, and South America.

13:49

They are carnivorous fish that eat other fish as

13:51

well as pretty much any creature they come across. You

13:55

might be thinking that the solution to many of these invasive

13:57

species is to bring in another species

13:59

that would prey on them. Well,

14:02

that's been tried, but the result is almost always

14:04

not what was desired.

14:06

Cats have been brought in to kill rats and rabbits,

14:08

but they often just hunt native animals, which are

14:11

easier to kill and have no fear of cats.

14:14

Almost everything has been tried to get rid of invasive

14:16

species, including poisoning, traps,

14:18

hunting, and bounty programs.

14:20

Save for small areas like South

14:22

Georgia Island or places with unique environments,

14:25

most programs to remove invasive species

14:27

don't work.

14:29

One promising technique that might have problems

14:31

all of its own is genetically engineering

14:34

versions of invasive species that can only

14:36

produce males.

14:38

These offspring could only produce males, and

14:40

so on and so on. If released into the

14:42

wild, they could eventually eliminate the population

14:45

by making it impossible to reproduce. At

14:47

some level, invasive species are a problem

14:50

that will probably never go away. We can't

14:52

put the genie back into the bottle.

14:54

We are much more aware of the problem than we

14:56

were just a few decades ago, and the idea

14:58

of releasing alien animals into an ecosystem

15:01

is seldom done anymore.

15:02

However, there are so many invasive

15:04

species that in many cases they're

15:07

so well established that it may be impossible

15:09

to ever remove them.

15:11

So if you ever do visit Australia

15:13

or another island country and you have to go

15:15

through some sort of biosecurity control,

15:18

just keep in mind that there's a pretty good

15:20

reason why they do it. The

15:25

executive producer of Everything Everywhere Daily is Charles

15:27

Daniel. The associate producers are Thor Thompson

15:30

and Peter Bennett.

15:31

Today's review is a re-review

15:33

from Apple Podcasts in the United States. Listener

15:36

Disappointed and Confused updated the review that

15:38

I read several episodes ago.

15:39

They now write, I would

15:42

like to go on record as saying that I am very ashamed that I

15:44

missed your correction about Anchorage. I am truly

15:46

sorry about my last review. Over

15:48

the course of the last year, my wife and I have had

15:50

so many amazing conversations because of your podcast.

15:53

We both feel like you are a friend of the family, Gary,

15:55

and we both apologize sincerely. We

15:57

hope everyone listens to the show anywhere they are.

15:59

are every day.

16:01

Thanks again, Gary. You're amazing.

16:03

Well, thanks, disappointed and confused. You

16:05

know what? Don't worry about it. Everybody

16:07

makes mistakes. I made a mistake, which

16:10

was the impetus for your first review. I

16:12

acknowledged the mistake and corrected it.

16:14

You acknowledged your mistake and corrected

16:16

it.

16:17

And that's really the best we can do. We acknowledge

16:19

our errors, and then we move on. Remember,

16:22

if you leave a review or send me a boostogram, you too

16:24

can have it right on the show.