6 Surprisingly Helpful Invasive Species


[♪ INTRO] Invasive species are bad, right? At least, that’s what you always hear. Like, take the brown tree snakes that accidentally
showed up on the island of Guam around 1950. With no natural predators,
these snakes reproduced like crazy and ate everything they could
get their imaginary hands on. After a few years, they had wiped out the majority
of Guam’s native forest birds. So, not good. These kinds of non-native species
are generally referred to as “invasive”, and they’re usually considered some evil that
needs to be eradicated from their new homes. But, not all non-native species are totally terrible! Here are six of them can actually
do more good than harm. One of the most surprising examples of a helpful
invasive species is the horse. Many people don’t realize that horses are
non-native to the United States, because they’ve been living
in the U.S. for so long. But they haven’t always been here. Although the genus Equus
did evolve in North America, all of the horses’s ancestors were extinct
from the continent around 10,000 years ago. And we still don’t know exactly what happened. Horses only returned to the area in the 15th
century, thanks to the Spanish colonizers. But even then, their comeback wasn’t all
sunshine and roses. Many of these horses escaped
and became feral, animals that were once domesticated
and have since run wild. And today, many groups
consider them an invasive species. These horses compete for the land
and resources used by other animals, and they have a tendency to smash vegetation
and damage plants by overgrazing. Still, when these feral horses are
removed from the wild and trained, they become some of our most helpful partners. For centuries, domestic horses have been invaluable
in moving people and supplies around the U.S., and parts of the country likely wouldn’t
have been settled as quickly without them. Even today, hundreds of feral horses
are taken in and trained each year, and even though fewer people
are using them to explore the country, they’re still doing important work
on farms and ranches. And as a bonus, they’re not
out there wrecking the plant life. Of course, lots of them are still
causing trouble in the wild, but at least some of them have
found more productive roles. Of course, no matter how many plants they
eat, people still love horses. The same can’t be said for another non-native
species, called the Tamarisk shrub. In the nineteenth century, various species
of this shrub were introduced to the southwestern U.S. from Eurasia and Africa. And initially, most people were pretty cool with it. The shrubs prevented soil erosion, and they served
as both ornaments and as sources of shade. And since they were drought resistant, they
certainly didn’t mind living in their new home. But then, their reputation kind of tanked. When the area’s water supplies
began to run low in the 1930s, the shrubs were accused
of being water thieves. They were even called ‘alien invaders’
during World War II. People kicked off decades of eradication efforts
to try and get rid of these plants, but as it turns out, they might have
just gotten a bad rep. Several studies have since concluded
that the tamarisk’s water use isn’t significantly different from
that of native tree species. And the shrubs are also doing
some good in the world. Specifically, they’re beneficial to a type of native
bird called the southwestern willow flycatcher. These birds live in the vegetation
alongside rivers and streams, things like cottonwood and willow trees. But they’ve become endangered as the
water has been diverted for other uses, and the vegetation has disappeared. Thankfully, the tamarisk shrub unintentionally
came to the rescue. According to recent research, up to 75% of
southwestern willow flycatchers have found new homes in tamarisk shrubs,
at least in some spots. The studies also suggest that babies raised
in tamarisks were just as successful in life as those from nests built in native trees. So it seems like the tamarisk isn’t such
a villain after all. If you’ve spent any time exploring the outdoors, you might have come across a bunch
of stringy flowers called honeysuckle. There are a few different species, and they’re
native plants in many parts of the world, but not central Pennsylvania. Honeysuckle probably wasn’t
introduced there until the 1800s, but it’s now thriving in a region
pleasantly called Happy Valley. In fact, its fruit makes up more than half
of all the fruit found in the area. Although this non-native plant does
compete for resources with the locals, it doesn’t seem to be causing too much trouble. In fact, it’s really helping out the birds! A few years ago, researchers started
some very dedicated note-taking, comparing bird and plant data from urban,
agricultural, and forested areas. And they found that the amount of
honeysuckle predicted both the numbers and diversity of birds within their studied region. In other words, the more honeysuckle, the
more birds and more types of them! The team actually determined that the honeysuckle
and bird communities had formed a mutualistic relationship, where the birds would eat their
fruit and poop out the seeds elsewhere. One gets nutrients it needs to live, and the
other gets to spread around its seeds. The honeysuckle has improved the lives of
other native plants, too, like nightshade. In one experiment, birds removed 30% more
nightshade fruit in areas full of honeysuckle, compared to areas without the invasive plants. That’s because these birds aren’t picky
eaters, so when they stop by for some honeysuckle, they nom on some nightshade fruit too. It’s more than a win-win. It’s a win-win-win,
at least for these three. You might not have heard of it,
but one of the most hated invasive species around the world
is the European green crab. It’s originally from the northeast Atlantic
Ocean and Baltic Sea, but it’s now colonized many of the world’s coastlines, spreading
on ships and ocean currents. And it’s a total troublemaker. These crabs chase off and kill native species,
and they eat basically everything. You might even say they’re acting a little
shellfish. But there’s one area of the world where they
might be doing a little bit of good: Cape Cod. European green crabs arrived in New England over a
century ago and began their usual terrorizing routine. But things in the region have changed a lot
since then. Over the years, recreational fishing and crabbing
have taken out a lot of the native species in the area, including the predator to the
native purple marsh crab. Without any enemies to munch on them, these
crabs then over-ate the local cordgrass, and dug so many burrows that
soil erosion dramatically worsened. But fortunately, the purple marsh crabs are
no match for the little green invaders. Studies have found that in places where green
crabs have made a home, the ecosystems are recovering from the damage done
by the overpopulating native crabs. Basically, this invasive species is a violent bully. Green crabs either outright kill or just scare the
marsh crabs so they spend most of their time hiding. When researchers stuck both species
in the same cage, the green crabs evicted the marsh crabs from their
burrows, and over 85% of them died. Another month-long test showed that the mere
presence of a single green crab caused marsh crabs to spend basically the entire time hiding,
even if the green crab was locked up. By the end of the month, the marsh crabs had
eaten much less cordgrass than usual. It’s kind of like a crab cage match. Two crabs enter. One crab leaves. Another coastal invader that’s helped improve
damaged ecosystems is Gracilaria vermiculophylla, a seaweed native to waters near Japan. Over the years, it’s spread around the North
Atlantic, likely due to the export of oysters, and you can now find it scattered across beaches,
looking like gross bunches of matted hair. Besides outcompeting native algae for resources,
this seaweed can also form dense mats in places like shallow bays and estuaries, which get
in the way of all kinds of stuff. These mats do things like blocking light from
reaching lower photosynthetic life, decreasing the amount of oxygen,
and shifting current flows, which affects how food settles for deposit feeders. However, studies have shown that where native
habitats have declined or disappeared for other reasons, Gracilaria provides some much
needed vegetation. It can bring back the area from the brink
of barreness. Other algae and small immobile animals can
attach to it, and it can provide shelter and food for other critters, like gastropods,
crustaceans, and other small invertebrates. Outside the water, the seaweed is also widely
used in agar production, a gelatinous substance used as a food thickener and in petri dishes. So it’s a bit of a mixed bag, but we’re
glad it’s doing some good out there. And finally, sometimes we intentionally take
species and bring it to a new land to help. This can totally backfire, but in the case
of the Aldabra Giant Tortoise, everything seems to be working out okay. Giant tortoises are a trademark of the Galapagos, but they’re also found on islands
in the western Indian Ocean. Initially, two main groups lived on
these islands: the giant tortoises inhabiting the Seychelles, and those living on
the Mascarene islands east of Madagascar. And then, humans showed up. By the mid-1800s, nearly all of the tortoise
species on the islands had been knocked out. Many were over-harvested by humans, and others
had their young killed by invasive cats, rats, or dogs. In the end, only the Aldabra Giant Tortoises
survived. They live in a place appropriately called
Aldabra in the Seychelles. It’s an island atoll, or land linked up
by a ring-shaped coral reef. It’s pretty isolated from the other islands
in the area, and an atoll doesn’t have enough space for human settlement, so that’s probably
why it currently has the largest population of giant tortoises in the world. And now, some of them have been purposefully
transplanted to other islands where their tortoise cousins no longer exist. For example, islands in the Mascarene,
like one called Mauritius, have seen a decline in certain fruiting plants,
because their seeds are no longer being distributed by extinct native tortoises. So in the year 2000, a group of Aldabra giant
tortoises were brought to the island. And now, they’re chowing down on the local
flora, pooping seeds out all over the place. In fact, their digestive process actually
helps break down the protective outer coating of some of these seeds, which makes
the chance of germination higher. The tortoises are also successfully
breeding on the island, and there have been similar success stories
in other places in the Mascarene, too. All these species make you wonder if it’s
time to retire the term “invasive” species. After all, none of them, whether they’re
good or bad for their new environment, are actively choosing to invade. There’s no green crab or seaweed generals
ordering their troops around. They’re just plants and animals that wound
up in a new land that’s way easier to live in. Either way, these non-native creatures shouldn’t
all be painted with the same brush, and by studying them rather than
immediately trying to remove them, we might be able to find ways to help
protect struggling ecosystems. Thanks for watching this episode of SciShow! If you want to learn more about invasive species,
we have another episode about that, and if you just want a new SciShow
in your subscription box every single day, hit that little subscribe button. [♪ OUTRO]

100 thoughts on “6 Surprisingly Helpful Invasive Species”

  1. Of course we shouldn´t remove the term 'invasive species'. It is the only term where most people are ok with killing off an entire group of animals or plants that is wrecking the ecosystem.
    People have generally accepted the term and understand the need from ecological perspective.

    "We're gonna kill these bunnies"
    "What?? Why??"
    "Its an invasive species and we don´t like what they´re doing."

    "We´re going to kill these bunnies"
    "What?? Why?"
    "We don´t like what they´re doing."

    One of these dialogues can expect a shitstorm and be forced to do an information campaign. The other, answer a handful of letters from thirdgraders.

  2. Despite weather you love it or hate it, and despite your efforts, no one will stop what has been started.

  3. Yeah white people aren't one of those good invasive species they should be removed and sent back to their f*** where do white people originate from

  4. according to the USDA plant database (plants.usda.gov), coral honeysuckle (shown at 3:21) is indeed native to Pennsylvania… NOT an introduced invasive species. Japanese honeysuckle, with yellow and white flowers, is introduced to the united States.

  5. horse? really? if you wanted to list species that were useful to us you could just list every imported livestock from anywhere…

  6. European Honey bees. With out them many of the food crops we brought over from Europe wouldn't have survived.

  7. Figures. Invasive species are a problem that humans create, and in the rare cases where they are beneficial, it is because they are correcting a different problem that humans created.

  8. We have diffrent words for diffrent species. The term you are looking for for non-native beneficial species are "naturalized species" like carp or arguably earth worms.

  9. You suck, stop spreading misinformation. There is a difference between invasive species and noxious species. Tamarisk is a noxious weed, it causes massive harms to local and regional ecosystems. Tamarisk is bad for the environment both locally and regionally, it leads to higher salinity levels in the rivers of the South West, causing the deaths of many endangered native fish. As for the Willow Fly Catcher, we could just replant the willows that Tamarisk out competed and made endangered.

  10. If an introduced species isn't ousting or killing native species, it is not called 'invasive', usually an introduced species that fits in without negative impact is called 'naturalized'.

  11. Wow SciShow, really disappointed in this video. For being made by a company called complexly I feel like you REALLY oversimplified the problems that many of these species actually pose to there environments that they're introduced to.

  12. I could be mistaken but I think it was the Comanches once they acquired horses they built a nation they were conquering other tribes with him that horses arrived in the Americas I think in the 1500 however there was a pre-existing population of horses in the Americas that went extinct so according to Wikipedia horses existed in the Americas before they existed elsewhere it went extinct here and we're reintroduced when the Europeans started colonizing.

  13. As an Ecology Major and soon to be Conservation Masters this episode made me cry.

    Seriously, not only did you conflate 'exotic' and 'invasive', you (as others have pointed out) cherry-picked and oversimplified the subject of invasive species to oblivion.

  14. This title is false and clickbaity: Invasive Species are by definition detrimental to any environment. Non-native species who enter an environment and don't harm it and integrate into it soundly are called Naturalized Species…

  15. I've heard about another case, beavers at Tierra del Fuego. They're an invasive species if ever any can be said to be, the forests of those islands have been changed into faster growers. Many proposals have been made by Chilenians and Argentinians to get eradicated but decision is still out. And locals have noted that where beavers build their dams, freshwater fish gets far more common and big. So Fuegians both love and hate beavers.

  16. The only people wishing to do away with the term "invasive" are people with one side of their head shaved and septum piercings and drove a car their dad baught them in college,
    or the reek of patchouli and weed. or both.

  17. Wild horses, you need to update your information they have now found that the Apaloosa horse came across the Bering Strait and the Appaloosa that the Nez Pierce Indians road are related genetically through DNA with the Mongolian Appaloosa. They are not from Spain. When Lewis and Clark came across to the pacific they saw tens of thousands of Appaloosa! Through attrition theft by the white man and the wholesale selling off of their horses War, etc. There are only 109 purebred Appaloosa left in the United States and the world that are registered. It has been proven that the Appaloosa came from Mongolia genetically and they're hoping to improve the line by cross breeding with the Mongolian Appaloosa that are the pure line. You also did not comment about the Oregon wild horse, which is a true wild horse related to the wild horse of Russia/Ukraine border near Chernobyl. This is a true wild horse that can't be domesticated. They are unfortunately hunted for meat. Even though the countries have tried to allow it to roam wild near Chernobyl so that it could improve and grow in size, the hunters have taken it from what should have been a 250 head herd down to 75. So where did the ones in Oregon come from? They've been there all along, they came across the Bering ice path and got trapped in the Northwest and stayed there.

    Horses in other areas of the continents, South America, etc, unfortunately, were hunted for meat, as they were one of the larger edible mammals and became extinct especially in South America. Where from Mexico all the way to Argentina, horse meat is still considered a delicacy and very, very edible.

  18. Ants, ants have invaded every continent except Antarctica and they are really helpful little creatures

  19. Great. Now tell us what to do with Florida and their Python, lionfish, cane toad, giant snails, frogs, and lizards. Pythons alone have eaten 90% of animals in the everglades.

  20. Part of me just can't get too outraged about invasive species, as if WE should talk about taking over foreign environments.

  21. I don't know man… I once saw a battalion of green crabs organizing off Cape Cod and they were armed

  22. Biological pollution (introduction of invasive species) is by and large a disaster. It's often immensely difficult to predict accurately how a species will behave in a new location, with different species and ecological niches. Some species are specialists, while others are generalists, the latter likely representing the greatest threat. Every species has its own fungi, microorganisms, parasites, predators etc., and these are typically absent when it's transported (often unintentionally), beyond its natural range. It will likely have an unnatural and inherent advantage over native species (which will have their own dedicated parasites, microorganisms, & etc.). Native species, which will have evolved in the absence of the invader, will likely not cope well with this additional threat. The Aldabra tortoise is an exception, because it sounds like a good fit for an unexploited ecological niche on Mauritius that resulted from human caused / aided extinctions (which included the Dodo).

  23. Another benefical invasive species " Indian People ! " cheap healthcare , better phone repair services than the Istore and the some of the best exotic takekout in the world !! I'm an Indian guy by the way.

  24. In Lake Erie the invading Zebra Mussel has cleaned the water. For decades industries dumped pollution in the Lake, in some cases turning it an almost neon green. The Zebras filter out the pollution as they feed.

  25. Useless video.. But good job climbing that ladder of ethics to provide your "fans" with redundant information that hasn't been relevant ever just so you can have a paycheck each month…

    Nice subject tho..

    Isn't there a specie of fish eradicating all other life in the north american lakes and rivers??

    No you're right.. Lets do a video about how horses should be considered an invasive specie to north america even though as we said earlier in the video they used to roam the planet long long ago anyway..

    But no yes.. let us provide even more misinformation to the masses!!!

    Human: OMG LOOK AT THESE MONKEYS!! THEY LOOK LIKE THESE MONKEYS ON THIS ISLAND AND OMG OVER HERE THERES MORE ON THIS BIGGER ISLAND!!!
    Alien: Hits space hookah with trepernon hidroclaxi Dude !! Come look at these idiots!! They forgot about pangea! hahaha

  26. Maybe that is the way this was supposed to happen? Whats the difference between migration and 'invasion'?

  27. I remember taking apart honeysuckle flowers for their nectar as a kid. That's a plant that makes me very nostalgic.

  28. We have feral horses here in Australia. They get shot but only after resources have been exhausted in catching them. Camels are similar but are shot on sight. Same with cats, dogs, foxes, rabbits, and some native species that have benefited from the introduced species.

  29. Horses in Australia do way more harm than good and should be culled. Food isn't the only problem, heavy hoofed animals destroy the natural habitat of hundreds if not thousands of different species in many ranges throughout our country.

  30. So if aliens invaded Earth, took it over and did a better job taking care of the planet, would they be helpful invaders?

  31. Man the main definition of invasive species is "non endogenous species that have unfavourable effect on the new habitat"
    What you are talking about is called "naturalized species "

  32. so the basic argument is that an invasive species is better than no species at all in ecosystems where an extinction has recently taken place…reasonable chance of that being true in most situations.
    seriously though, there are FAR more cases of Kudzu or wild boar or, well, humans.

  33. Non-native rarely means invasive. I feel like you're being a bit deceptive to drum up interest. Lame.

  34. It's amusing how many people here are operating under the assumption that this video says these species are good. It doesn't. Maybe you all should WATCH the video.

  35. One "invasive plant" is scotch broom its an evergreen shrub with yellow flowers. Its a horrible plant that's taking over the Pacific northwest. I'm allergic which makes it worse

  36. I've introduced a non-native species to my off-grid 20 acre property where a major wildfire rages through about every 8 years. In 2006 as we were in the process of clearing land for our house (back-breaking work), an arson fire swept through here and burned all my neighbors homes. Most tragic of all, it took the lives of five wildland firefighters. We had too much invested to give up, so once the house was built and we were living here, I decided to get goats! As many as I could support. I found many free ones that were former pets. Six years ago, another fire raged through. My son and I weren't able to evacuate, but two fire engine companies came and stayed in our driveway during the ordeal while we were all completely surrounded by flames. Thanks to our goats, there wasn't so much as a blade of grass near the house so we all survived and had no structure damage. Before the crews left, the Captain said, "Your goats SAVED your ass!" I smiled pointed at the hill where they had been parked hours before which was STILL burning and said, "Might have saved yours, too!" One firefighter told me he and his wife had just moved up here on the mountain, he told me he'd already called his wife and discussed getting goats asap! Cutest brush removal machines ever, and they never throw sparks.

  37. Have you lost your damn mind? Green crabs have completely destroyed the New England clam fisheries, and are not edible. They benifit us because we killed the predators of one native species and green crabs helps control them? How is that good, they do a huge amount of damage. Very bad video.

  38. Wow! SciShow!
    Was this episode bought and paid for by the cattle crooks or what?!
    You should have said feral horses compete with COWS not wildlife.
    And that mafia cow farmers want all of Americas public land to graze for cheap and that the horses are in the way of them achieving that. So they round them up with helicopters and throw them in a pen for the rest of their miserable lives. That’s the real story.
    For shame, SciShow.

  39. So basically, when humans came to the new world over the Bearing straights, they were an invasive species.

  40. Some wild horse advocates argue since horses are in fact native to North America and were merely reintroduced to their ancestral range, they aren’t an invasive species at all.

  41. I think you may need to change your title & clarify exactly what you're trying to convey. When seeing the title, my first thought was that this was going to present species that are "not natural" yet have not done harm. Your term of "non native" fits better imho. What you have presented, however, is a list of invasive species, but have been found to be helpful or beneficial in "some" way, shape or form.

    From NOAA…
    An invasive species is an organism that causes ecological or economic harm in a new environment where it is not native.

    That would mean that what we have here is a list of invasive species that are not invasive in all cases, as opposed to being invasive & helpful. Calling them invasive & helpful is oxymoronic because if it's invasive, it cannot (by definition) be helpful.

  42. As a wild life biologist this video is dangerous… very dangerous and misleading. Horses are also one the most invasive and damaging ecological species on the land scape right now

  43. Europeanbuckthorn chokes all other trees, sickens birds, and gouges the eyeballs of Humans with it's thorns.

  44. "Burning your house down is generally considered a bad descision – but you will have it warm for a moment!" – the video

  45. "many people dont know that horses arent native to America"

    yeah, we call them public school students

  46. Uhhhh invasive species are never a good thing lmao??? All of these species do one good thing but completely devastate other ecosystems & push native plants to extinction. I'd be hardpressed to say just cause they helped return balance to one ecosystem humans damaged while their relatives are off destroying another twenty ecosystems that they're "doing more harm than good."

  47. liberals are going to try and remove the tern invasive species. liberal scientists have found that the term invasive is offensive to european green crabs and other species.

  48. Um, honeysuckle is super invasive and its strangling other plant life in northeastern oklahoma. People are steadily doing burns to get rid of the honeysuckle and it does way more damage than good

  49. Sounds more like: humans destroy nature, sometimes nature gets lucky and is helped rather than even more destroyed by an invasive species brought in by humans….

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