Eli5: how do invasive species work?

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When you see lion fish or anacondas as invasive.. how does that work? If they live there how did they get there and what does it do to have invasive species that people are just killing animals to prevent it?

In: Planetary Science

6 Answers

Anonymous 0 Comments

Invasive species generally refers to organisms that are introduced to an area to which they are not native by human activity. This can happen in a few ways. They can be accidentally brought over in freight or ballast water, they may escape or be released from captivity, or they may be deliberately introduced.

Pythons from southern Asia have been introduced to Florida. Many of them were originally kept as exotic pets that were released by irresponsible owners. But now the pythons have established a breeding population.

Some invasive species of fish and algae have escaped from aquariums.

Foxes were introduced to Australia by British colonists who wanted to hunt them for sport.

Once they are introduced, they can disrupt local ecosystems by eating or competing with native species

Anonymous 0 Comments

An invasive species is one that has been brought from a completely different part of the world to a new place. In that new place, the invasive species *usually* (but not always) has adaptations that make it MUCH better at surviving and reproducing than other species that live the same way it does (e.g. other bushes if it’s a bush, other trees if it’s a tree, other predators, etc.) As a result, this harmful invasive species outcompetes local animals and damages the biosphere by making it less diverse and more sensitive to environmental catastrophe.

Usually, invasive species today are the result of humans carrying species around with us, sometimes intentionally, sometimes by accident.

Lionfish are a good example of an invasive species. In their native waters, they have predators that can handle the lionfish’s poison, and they have competitors who can eat food faster than they can, so their voracious appetite is balanced out by effects that reduce their numbers. In the Atlantic, where lionfish have been accidentally introduced, they have few to no predators because of their poisonous spines, and they can eat food much faster than other species, thus driving the native species out, potentially depleting both their food sources *and* the native life that used to feed on them.

Clover, on the other hand, is an arguably beneficial invasive species. It’s native to Europe, but has spread all over North America. It isn’t any better at being a ground cover flower than any other ground cover plants, so it doesn’t really have any effect on that. But it *does* provide some nice benefits, like giving bees another flower that grows at a different time of year, thus helping them eat more.

Unfortunately, most of the time, a successful invasive species is going to be more like lionfish than like clover. You need a very careful balance of factors for a new species to fit so nicely into an existing ecological region. If the species falls short, it won’t be able to survive and will die out. But if it’s too good, it will become a nuisance and a danger. The Goldilocks zone is small here, and few species manage to fit into it.

Anonymous 0 Comments

They’re invasive.

By definition they don’t normally live where they are invasive. For invasive marine life, things often end up in new places by hitching a ride on a ship that’s going between different oceans, lakes, rivers, etc.

Invasive species generally don’t have any natural predators where they’re invasive and they can destroy existing ecological systems because they’re unchecked

Anonymous 0 Comments

Humans put them there, either on purpose by releasing them from captivity or by accident when they took a ride with forty tons of bananas on a cargo ship.

They’re a problem because they’re now in an environment that hasn’t had hundreds of thousands of years to evolve with them. A Boa Constrictor that gets loose in Florida will find an environment with lots of easy prey and very few predators adapted to hunting large snakes. They populate out of control because they eat everything and nothing eats them, and native reptiles get squeezed (literally sometimes) out.

Anonymous 0 Comments

There is a two-pronged test to determine if something is an invasive species:

1. Is it non-native to the ecosystem; and,
2. Does it cause or is it likely to cause economic or environmental harm or harm to human health?

The vast majority of introduced species are not invasive, but the few that are can cause a massive amount of damage.

In virtually every case, invasive species are introduced by humans, either intentionally or accidentally.

Anonymous 0 Comments

in most cases invasive species get introduced by humans, we transport them somewhere else either intentionally or unintentionally and once they are there they start spreading.

Ecosystems have formed over millions of years and have developed a balance of where all species that exist at the current time are co existing.

This usually means that there are predators that will feed off other animals and keep that population in check while the other way around the population of the predators is kept in check by how much food is available to hunt for them.

Now when we talk about invasive species that can mean all kinds of things but in most cases these are animals introduced into an area where they have no predator that would keep their population down so they will reproduce uncontrollably and displace other native species by eating their food or taking their breeding grounds.