January 27, 2025

Invasive Species and How They Are Introduced Into Ecosystems

Invasive species as defined by the National Ocean Service - National Oceanic and Atmospheric Administration, organisms which cause ecological and/or economic harm in a new environment it is not native to (NORA, 2024). These organisms are introduced into ecosystems almost always by human activity, with one way example being through ship ballast water, that is, water stored in a ship’s ballast tanks and cargo holds in order to help improve both stability and movement. As a ship collects water in one area, the ship also collects aquatic organisms, bringing those organisms to a new area when the water is discharged after reaching their destination. Invasive species are spread through other transportation means as well, such as through motor vehicles or aircraft, as organisms can make their way into wood, crates, and other shipping materials which are then transported across the world.

However, invasive species can also be spread intentionally, such as through horticulture (a type of plant agriculture regarding ornamental gardening), pet trade (obtaining exotic organisms for pets which may then lead to their release into new ecosystems), and biocontrol attempts (introducing species into new environments to help control an already-established invasive species but may become invasive themselves).


What Impact Do They Have on Biodiversity?

Every ecosystem has a unique set of characteristics: an orderly food chain with balanced species competition at each level, established prey-predator dynamics and supply, specific habitat distribution, and more. However, when an invasive species is established, they cause disorder within all of these aspects. Entering the food chain as a predator, they begin competing for the same resources as other species at their level. In some cases, they can be more able than the native species, outcompeting them for resources, leaving the native species with a waning food supply and potentially causing their population to decrease. As prey, the invasive species introduces a larger food supply for the native predators, allowing their population to potentially increase out of control, hurting the native prey populations. As for habitat, as the invasive species establish themselves in the new ecosystem, they take away habitat space from native species, again harming those populations. As a result of all of these factors working together, the ecosystem’s biodiversity decreases as the native species experience population decline while the invasive species becomes dominant.


What Are Some of the Most Problematic Invasive Species in the U.S?

Some problematic invasive species found in the United States are the Free-Ranging Cat (felis catus), Emerald Ash Borer (Agrilus planipennis), Feral Swine (Sus scrofa), Red Imported Fire Ant (Solenopsis invecta), and Hemlock Woolly Adelgid (National Park Service, 2023). All of these species significantly harm the country’s ecosystems and native wildlife by interfering with established food chains, altering interspecies competition, and also taking away habitat space.


Why Should We Care and What Can We Do?

Invasive species, if left unchecked, will greatly harm the environment and economy, but especially native communities. As they interrupt natural ecological processes, native populations could potentially be hurt to the point of extinction, as they are outcompeted beyond recovery, greatly reducing local biodiversity. This is an issue because we rely upon local biodiversity and native species for various purposes, such as for consumption, building materials, agriculture, and more. When our native species are harmed, they can no longer fulfill their roles in both their ecosystems and for human needs.

Thankfully, there are many ways every individual can help combat this issue, starting at the very beginning. Ensure that all plants and animals you obtain for gardening or companionship are not invasive, clean your aquatic vehicles thoroughly before transporting them into new waters, clean body items (boots, pants, shirts, etc.) before bringing them into new land areas, and don’t release plants or animals into the wild without first checking if they’re invasive. On the other hand, there are solutions for combating already established invasive species. If you believe you’ve found an invasive species, you can contact your local land manager or the local USDA office. You can also use the National Invasive Species Information Center for more resources regarding how and where to report potential invasive species.


References:

https://oceanservice.noaa.gov/facts/invasive.html#:~:text=Invasive%20species%20are%20animals%20or,and%20most%20often%2C%20by%20people

https://www.invasivespeciesinfo.gov/subject/ballast-water

https://education.nationalgeographic.org/resource/people-and-invasive-species/

https://www.nwf.org/Educational-Resources/Wildlife-Guide/Threats-to-Wildlife/Invasive-Species

https://defenders.org/blog/2023/08/how-do-invasive-species-affect-biodiversity-and-how-can-they-be-controlled#:~:text=Through%20predation%2C%20competition%20for%20resources,contribute%20to%20healthy%20native%20ecosystems

https://www.nature.org/en-us/what-we-do/our-priorities/protect-water-and-land/land-and-water-stories/invasive-plant-species-invasive-species-education-1/