What Are Invasive Species, and How Do They Impact the Environment?

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If you’ve ever traveled to another country, you may have had to verify that you weren’t traveling with a long list of items. Those lists usually include things like weapons, drugs, and certain foods. And, surprisingly, almost all of them check for animals. The process also happens when you’re returning home. It’s understandable that you wouldn’t be allowed to travel with certain dangerous items — but where do animals fit in? As it turns out, these restrictions are meant to keep invasive species from doing serious damage to the places people travel to. 

Countries don’t want you bringing home unwanted illegal souvenirs. But why are governments so concerned with animals entering and exiting their countries? It’s because politicians and scientists are (rightfully) concerned about the effects of invasive species. 

An invasive species is a living thing that’s brought into a new habitat. This new species slowly takes over its new environment and can even be very harmful to it. Additionally, invasive species are animals or plants and can even be organisms like fungi and bacteria. Human activity is often at the root of an invasive species’ entrance into a new ecosystem and as a result, different countries have laws and regulations to prevent their spread. 

In addition to impacting local wildlife, invasive species can affect farming, fishing, and other industries, which in turn affects livelihoods and economies. To understand their full impact, let’s break down what invasive species are, look at a few examples and find out what’s being done to prevent their presence today. 

What Are Some Examples of Invasive Species?

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Everywhere across the world, different areas have plants and animals that are native to those regions, meaning they evolved to exist there and weren’t introduced by humans. In contrast, an invasive species is a living organism that isn’t native to an area. Instead, people likely brought it there. And because it didn’t evolve to coexist with other living things in the region, it can behave in a way that is harmful to the native species. To get a better understanding of exactly what they are and what they can do, it helps to see a real-life example.

Burmese pythons were a popular pets in the 1990s, especially in Florida, where many families kept the nonvenomous snakes as companions. Some people ended up releasing these pet snakes into the wild after the animals grew too large (see the photo above to get a clear idea of their size). The Burmese python, which isn’t native to Florida, still thrived in warm climates, especially in the Everglades. 

Soon, the Burmese python began to take over habitats and entire ecosystems. While Florida’s population of Burmese pythons skyrocketed, other species began to lose out. A 2012 study looked at remote areas of the Everglades National Park and found population drops exceeding 99% for raccoons, opossums and bobcats. Foxes and multiple species of rabbit “effectively disappeared,” according to the U.S. Geological Survey. This may sound like science fiction, but a lot of fictional disasters are based on real-life fears.

If you’re looking for an example of invasive species that are a little closer to home, consider phragmites. This tall, furry grass can be found all over the U.S., especially on coastlines. Phragmites are known as a common reed, and it’s practically everywhere, from California to Michigan to Idaho. Because phragmites grow near water, they can restrict water flow and block access to water for animals and people. Phragmites aren’t friendly for birds building nests or for reptiles that thrive in wet conditions.  

Other top invasive species in the U.S. include cane toads, common carps, zebra mussels, stray cats, Asian tiger mosquitos, Japanese honeysuckle, and American bullfrogs. Some of these species may be staples in nature for some people, especially young people. But even species that seem pleasant or “good,” like the Japanese honeysuckle, can dominate an ecosystem and hurt habitats. 

Legislation Aims to Prevent the Spread of Invasive Species 

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A number of laws and executive orders have been passed to prevent the introduction of invasive species into different ecosystems. For example, Bill Clinton’s Executive Order 13112, signed in 1999, established the creation of a council on invasive species. This is different from the National Invasive Species Act, however, which passed in 1996. 

The Lacey Act was passed in 1900 and was the first federal law in the U.S. that protects wildlife. The law limits the trade or acquisition of certain species and has been expanded over time to prevent the travel of invasive species. In 1992, Alien Species and Enforcement Act made it illegal to ship species covered by the Lacey Act via the mail. The list of species that are a part of the Lacey Act has grown throughout the years, most recently in 2008. 

Aside from the Lacey Act, legislation geared towards stopping the spread of invasive species picked up speed in the 1990s. The Nonindigenous Aquatic Nuisance Prevention and Control Act of 1990 was the first major piece of legislation to become a part of this movement that is very much still in its early stages. This law was a reaction to the findings that different ships were spreading species, some of which were invasive, around different water ecosystems.  

Other legislation, like the Nutria Eradication and Control Act of 2003, allocated resources to Louisiana and Maryland to deal with their nutria problem. Sometimes, populations of invasive species can get so out of control that people have to get involved and do what’s necessary to save a local environment. Sometimes, these solutions aren’t as humane as the prevention of invasive species and are more like last-ditch efforts to prevent their spread. 

It’s All About the Ecosystems That Need Managing

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If you think about it, invasive species impact the environment the way a pathogen can. Both are natural parts of life and are inevitable side effects of humans traveling the globe. If a virus or an invasive species isn’t prevented from entering an area or dealt with early after its introduction, it can turn into a much larger issue that can take years to undo — if the effects aren’t permanent. 

If you plan on traveling, be sure to look into any guidelines set by environmental departments and local governments at your destination. Doing so could prevent harm to plants and animals and help preserve the time and resources that are spent mitigating the impacts of invasive species.