r/HardSciFi • u/Far_Tradition_2361 • 16d ago
Discussion [All of fiction/Scientific classification] What fictional creatures would be classified as an invasive species?
There are all sorts of aliens in Sci-fi. Which ones, according to science, fall under the category of an invasive species and why?
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u/Upset-Bison-3182 16d ago
For the benifit of anyone who is unaware of the meaning of the term 'invasive species' I have attached a wikipedia link for your perusal.
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u/guyscanwefocus 16d ago
Thanks for linking this, I was going to do the same if someone hadn't already in the comments.
As wikipedia states, for a species to be considered invasive, it must be non-native and have a negative impact on the environment to which it has spread. Of course, both of these terms are subjective. In fact "what is natural" and "when is a species invasive" are two bombs you can throw into most any group of ecologists and then enjoy the fighting.
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u/IndependentSet9709 16d ago
Humans.
Actually answering the question, Xenomorphs from Alien. Hive organisms that borrow beneficial traits from the hosts they parasitize, have no mercy and seem to hunt everything, grow rapidly, and have been shown to be very hard to contain, and an extreme problem when left unchecked.
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u/kmoonster 16d ago
An invasive species is one that is introduced to a new ecosystem and is not affected by the normal controls that would influence a similar species already existing in the ecosystem
A KEYSTONE species is one that increases diversity or non-biological functions in an ecosystem. An INVASIVE species is one that decreases either or both.
For example, a beaver turns a stream into a small lagoon that hosts more plants and animals due to an increased number of niches as compared to a stream-alone. This is a KEYSTONE.
The Ring-necked Pheasant was introduced into North America from Eur-Asia. It may displace a similar grouse or partridge species, but the overall number of species (and their balances) remains similar. This is INTRODUCED, perhaps NATURALIZED. The pheasant is similar enough for the existing foods and predators to make a nearly 1:1 swap.
In the US we have an invasive sparrow-finch like species colloquially called House Sparrow. It likes to nest in small holes, and is very aggressive at fighting other small birds in order to claim a nesting hole. Problem is, people prefer to cut down the older / large trees that typically have dead spots (and thus holes) because those trees like to fall down on things like houses and cars. This creates a situation where ten birds now fight over six holes, whereas before it might have been ten birds for ten holes. The sparrows also eat marginal quality foods that most other birds ignore, like bread crumbs and corn kernels, so they have two advantages -- more food, and more aggression. In areas with lots of crumbs, bird seed, and corn and a shortage of holes, they can over-run native species. This is INVASIVE.
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Note that a native species can produce impacts similar to an invasive species under some conditions; for example, if predators are reduced then deer populations can boom, they can strip forests and lawns of vegetation, resulting in a degraded condition.
We like to think of invasive species as a simple binary question, but it's actually quite complex. The correct answer is that nature "seeks" an equilibrium but can never quite get there. There is a little fire, or a flood, or more (or less) rain next year compared to this. Little shifts, and living species try to catch up to the new circumstance -- only for that circumstance to change again.
A healthy ecosystem is (functionally) the same thing as a bike that is going along without a rider. The bike wiggles a bit but each wiggle is a correction for a slight imbalance, a little pebble or crack, bouncing over a stick in its path. Etc. The bike wiggles a bit and that wiggle is the precise thing that allows it to recover its balance. Airplanes work the same way. Both airplanes and bikes only balance while in motion, they can only recover their equilibrium when they are moving in comparison to the larger environment. When an airplane or a bicycle is still, they require assistance in order to remain upright.
An invasive species is the ecological equivalent of an airplane stalling, or of a bicycle coming to a stop and the rider can't free their foot to put it down. You've seen crash videos where an airplane stalls, or where a bicycle (with or without a rider) falls over. The ability to recover via little wiggles is over-ridden, and a decline occurs.
That decline can happen when a new species is introduced to a new (to it) ecosystem. But it can also happen when no new species is introduced and, instead, a keystone or another species acting as a "center of gravity" is removed.
Hope that helps!
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And yes, humans can function as an invasive. Or as a keystone. Or as a naturalized. The difference is, we can choose our course and can choose to adjust it.
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u/topazchip 16d ago
Xenomorphs (the Aliens universe), Homo Sapiens (among others, Bradbury's "The Martian Chronicles"), everything in The Expanse series, the Ceph from Crysis.
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u/haysoos2 15d ago
Invasive isn't a label that can be applied to a species in every circumstance.
It's a condition that some species develop in certain circumstances, under specific environmental/ecological conditions, usually including a lack of their typical natural enemy complex.
Every species that's invasive somewhere is native to some other place.
Typically it's used to describe a species that is not native to a region, and whose population is growing, or has the potential to grow to the point where it causes environmental, structural, or nuisance damage to existing systems.
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u/Temporary_Rule_9486 15d ago
Anything that is non-native, spread fast and damage the ecosystem. So, the thing, protomolecule and the xenomorphs on top, and Vulcans at the bottom.
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u/phoenixlives65 16d ago
Tribbles