American Oceans

A Comprehensive Guide to Invasive Species

What Does Invasive Species Mean?

According to the Natural History Museum, an invasive species is either an animal, a plant or an insect that harms an environment, as a result of being introduced to that space by humans.

This is slightly different to a non-native or an introduced species, both of which are creatures found away from their usual environment as a result of humans, but aren’t necessarily causing any disruption and may actually survive better there.

Lionfish swimming near corals

How can we prevent invasive species?

There are several precautions one can take – or we as a society can do generally – in order to prevent the spread of invasive species.

These are only necessary to enact if you are visiting a country like Australia, for instance, where invasive species are prevalent and easy to come across.

  • Research plants before you buy them: ensure that anything you are planting in your garden is not considered invasive, and ask for assistance from anybody in your local gardening center or community if you’re having trouble identifying safe plants to get.
  • Make sure you never “take a pest” across state lines: this can happen accidentally, for instance if you go camping somewhere and happen to forage for firewood or other materials and then take those home with you.
    • Anything you move from one place to another could be potentially harboring hidden creatures, so be especially careful about what you’re transporting or accidentally smuggling!
  • Clean yourself up thoroughly after a hike, walk or climb: if you’re visiting new places, you want to make sure any seeds, spores or other pathogens you might have picked up from those areas are completely gone. Thoroughly clean all of your gear, including pockets, straps and any other nooks or crannies.
  • Never release animals from captivity into the wild: whether that’s an exotic pet or live fishing bait, you must not ever introduce any species to environments where they were not previously.
    • They will not only be a threat to themselves, but any other creatures in the area, and it could wreak havoc on the ecosystem.
  • Always stick to the beaten path: this goes for anything in life, but especially when it comes to invasive species.
    • If somewhere is inaccessible, unsigned or marked off, it will usually be for an important reason, like potential harm, danger or other risks. You could spread invasive species accidentally, just by exploring somewhere you shouldn’t!

How do you control invasive species of animals?

You will find there are three primary methods used to control invasive species across the USA, according to the National Invasive Species Information Center, a subsidiary of the US Department of Agriculture.

These would be chemical, mechanical and biological, respectively:

Chemical control involves using herbicides to prevent the spread of or control an invasive animal species, where biological control involves purposefully encouraging the natural enemies of a species to attack the invaders, thus removing them in a more natural way despite being the action of humans.

On the other hand, mechanical control requires a more physical approach to invasive species control: by hand pulling, cultivating, hoeing and mowing certain plants, it’s possible to minimize or control the spread of them.

It is also possible to follow a fourth method, which essentially involves the combination of all three control efforts described above, often referred to as Integrated Pest Management or IPM.

This is often the most preferred method of solving any problems with invasive species, as the primary purpose is to do so whilst simultaneously reducing or completely removing any risks to people or the surrounding environment.

Scientists use strategy and decision making in order to combine their tools and methods as a way of successfully controlling invasive species – this is an excellent way to reduce the use of pesticides, which are proven to largely cause more harm than good in the long term.

Are humans invasive?

That would depend on who you asked!

Although humans don’t technically come under the definition of invasive species, because we were not introduced to our ecosystem by other humans and we don’t cause intentional harm, there are arguments to be made for certain humans who cause environmental harm to the Earth and other species that inhabit it.

As we are autonomous beings that can pretty much do what we want – inside the parameters of the law, that is, although many of us tend to ignore it and face no consequences – we are able to do things that we should not in order to survive.

For instance, many of the illnesses that would naturally wipe us out can now be treated by science, despite killing millions of humans previously. This is one of the ways we have outsmarted nature and continued to thrive where perhaps we should not.

Likewise, the ways in which we continue to pollute the Earth, worsen global warming and wreak other havoc on our environment is very much causing damage to ourselves and other species, not to mention the planet generally.

Although humans don’t technically fit the scientific definition of what constitutes an invasive species, it could definitely be argued that we serve some similar purposes and are equally as selfish and unforgiving in our pursuits.

A paper in Scientific American’s August 2015 edition by Curtis W. Marean in fact argues that humans are the most invasive species of all – but whether you agree with that or not is up for you to decide.

What would happen if we left invasive species alone?

When not properly controlled or prevented from entering new spaces, invasive species have the potential to cause damage to the environment, economy or even human life. 

As they rapidly reproduce and grow at an alarming rate, they can cause huge damage and widespread harm in a short amount of time, so the proper control of them is incredibly important to the health of our ecosystem.

Failure to control invasive species might cause the loss of land and water, by taking over a certain area and making it inaccessible to humans, thus disrupting activities like boating, fishing, camping, hunting, hiking and other outdoor pursuits.

Likewise, by entering environments and food chains they should not belong to, invasive species can cause the endangerment or even extinction of native species, destroying their habitats or making them vulnerable and more susceptible to disease.

There are also invasive species that have the potential to threaten or endanger human life, whether by the carrying of dangerous pathogens or bacteria or through other means, like causing crop death or droughts because of ecosystem changes.

Should you kill invasive species?

Not necessarily! If it is possible, often it is much better for the species and their surroundings, as well as food chains more broadly, if you can successfully recapture and replace the invasive species somewhere it is less likely to cause any problems.

In the event that the invasive species is likely to cause a great deal of harm, it can sometimes be for the greater good to completely destroy them, as the harm that could be caused by failing to control them might outweigh that of getting rid of the invader itself.

Weighing up the risk-benefits and deciding what is best to do is always recommended – do your research on the specific species to be certain.

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