Name: 我們對抗外來物種的奇怪方法 (Weird Ways We've Fought Invasive Species)
Uploaded: 2021-01-14T10:37:03.000Z
Duration: 9 min 9 s
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關係子句

it's no wonder that species sometimes end up in habitats that aren't their own.

But these invasive species can cause serious trouble.

They often compete with native species for food, steal their homes,

nom on them for lunch, or otherwise wreak havoc in their new habitats.

The survival of entire ecosystems can depend on getting rid of them.

Without predators to keep them in check, invasive species tend to stick around and multiply,

despite our best efforts to fend them off.

That means that we have to get pretty creative to have any hope of eradicating them.

And in some cases, humans have risen to the challenge.

Here are five of the strangest ways that people have fought back against invasive species.

The brown tree snake invaded the tiny island of Guam in the 1940s,

after stowing away on a U.S. military plane coming from another Pacific island.

Since then, the snake population, which is now about two million strong,

has eaten its way through the island, devastating the local ecosystem.

The snakes have hunted ten of Guam's twelve native birds to extinction.

Without birds, the spider population has gone unchecked.

Forests have also thinned because there aren't enough birds to spread seeds.

To make matters worse, since these tree snakes live in trees,

it's tough to weed them out with traditional methods like traps or snake-sniffing dogs.

the U.S. government has been experimenting with a more creative solution:

air-dropping dead mice filled with acetaminophen,

the active ingredient in Tylenol, over the jungles of Guam.

The mice come sailing down in little parachutes, which is kind of tragically adorable.

and dangle the mice in places where snakes can find and eat them.

A year-2000 study by the National Wildlife Research Center found that

100% of brown tree snakes die after ingesting acetaminophen.

Unlike in humans, this medicine prevents the snakes' blood cells from carrying oxygen.

Just 80 milligrams of the stuff, about a child's dose of Tylenol,

makes the snake go into a coma and die within 60 hours.

Dead mice seem to work really well as a vessel for the poison,

because they attract the brown tree snake but not Guam's native species,

And so far, research suggests that this approach is pretty effective.

One study looked at a site where two rounds of poison-mice

The researchers found a 40% decrease in the number of baits eaten after the first round,

suggesting that there were fewer snakes to eat them by round two.

So this method could go a long way in clearing these invasive predators out of the island.

While the brown tree snake snuck its way into its co-opted home,

many invasive species waltz into foreign environments as pets.

That's probably how the spiky, colorful lionfish

got from its native Indo-Pacific seas to the Atlantic Ocean.

Lionfish have been terrorizing the Atlantic since the late 1980s,

taking over reefs, shipwrecks, and other places.

It seems likely that these invaders started out as pets

whose owners dumped them in the ocean when they didn't want them anymore.

Except, these fun, zany-looking fish are actually fierce predators.

They eat mostly fish and are super-venomous,

so they don't really have predators in their foreign territory,

which makes them pretty much unstoppable.

Lionfish have drastically reduced the populations of fish where they live.

Lionfish devour other fish that typically eat algae,

and unchecked algae growth crowds out coral reefs.

So lionfish are indirectly killing our reefs.

But it's not like we can just fish them out of the ocean.

Lionfish have been moving into deeper and deeper waters,

making them hard to catch with a hook and bait.

it gets too risky for divers to catch a fish with, say, nets

because the water pressure gets dangerously high.

So, to stave off the lionfish invasion, the the CEO of iRobot,

which made the Roomba, yeah, that little robot vacuum,

has developed human-controlled, pressure-resistant robots

Deep underwater, the goal is for these weird tube robots to track down lionfish,

give them a good zap to stun them, and then suck them up with a vacuum.

The good news is lionfish are a pretty easy catch.

Since they aren't used to having predators around,

they don't really run away from things that approach them,

even weird robots with little clappers attached.

Which is pretty convenient for the robot.

Along with clearing the water of invasive species,

this underwater robot collects lionfish that could ultimately be served at restaurants.

Lionfish actually makes a pretty tasty dish that some people compare to snapper.

As of 2019, the robot is still being refined, so it's not on the market yet.

and preparing the machine to suck the invasive lionfish out of the seas.

The lionfish isn't the only invasive fish that's been hard to root out.

In the Upper Missouri River Basin, brook trout from the Eastern U.S.

have been crowding out the area's native trout species since the 19th century,

when people introduced them as a way of replenishing fish populations around the country.

In the past, people have gotten rid of invasive fish

by dumping toxic chemicals in the river to poison them,

but it probably doesn't surprise you that that solution leaves something to be desired.

The toxins kill invasive fish and native fish alike, including ones we rely on for food.

a much safer way of removing the trout without killing everything else.

The technique is called backpack electrofishing, and it's pretty much what it sounds like.

Essentially, researchers wade into the water wearing backpacks with electric generators.

The generators are connected to wands with positive charge flowing through them,