Sample Topic: Invasive Species

Writer: Dhruvi Patel

Instagram: @_.dhruvi.patel_


What are Invasive Species?

Invasive Species refer to non-native organisms that have developed in a foreign land to cause ecological havoc. They threaten the livelihood of native wildlife and ecosystems and push them to the brink of extinction.[1] Approximately 42% of threatened or endangered species are at risk due to invasive species. They have also played a major toll on economies around the world. Due to their detrimental effects on the ecosystem, the cost of the rejuvenation can be up to billions of dollars each year. In order for a species to be labelled “invasive,” they must be able to grow and reproduce rapidly with the potential to do harm. Species that are native to one part of a country can be considered invasive in another part. For example, lake trout are native to the Great Lakes but are considered to be an invasive species in Yellowstone Lake in Wyoming because they compete with native cutthroat trout for habitat.[2]

How do Invasive Species Spread?

Invasive species are primarily spread by human activities such as through the transportation of the goods we use. Ships can carry aquatic organisms in their ballast water, while smaller boats may carry them on their propellers. Insects can get into wood, shipping palettes, and crates that are shipped around the world. Additionally, ornamental plants can become invasive by escaping into the wild. Some invasive species are intentionally or accidentally released pets and they can potentially reproduce with native species to become invasive. For example, Burmese pythons are becoming a big problem in the Everglades in Florida.[2]

As a result of climate change, with higher average temperature and changes in precipitation patterns, some plant-based invasive species such as garlic mustard, kudzu, and purple loosestrife move to new areas. Along with these plants, insects and pests travel causing infestations. Infestation caused by mountain pine beetle on drought-weakened plants have occurred due to climate change. [2]

Zebra Mussels

An example of a major invasive species throughout all of the Great Lakes, Lake St. Clair (between Michigan and Ontario) and the Mississippi River watershed is the Zebra mussels. Zebra mussels are freshwater mussels measuring around 2.5 centimetres in length. They are named for the dark, striped pattern on their sharp shell. They originate from the Black Sea region of eastern Europe and western Asia waters. These pesky species were first observed in 1988 in Ontario, and they have now made their way into Lake Winnipeg.

Zebra mussels are known to be highly adaptable as they can survive in a variety of water temperatures and conditions. They also reproduce rapidly as a single female zebra mussel can produce up to a million eggs per year. The eggs are free-floating so they can be picked up by water currents, winds, and waves which allows them to quickly spread in large numbers through the water. A few weeks later, after the eggs are released and the larvae develop, they secrete sticky fibres to attach themselves to any hard surface within the water.

Zebra mussels are extremely harmful to the native ecosystems in great lakes. Due to their food intake, they filter water by removing plankton. One mussel can filter up to a litre of water per day. Plankton is also the food source of many native wildlife such as the species, Lake herring. Due to the zebra mussels consuming plankton, they ravage the ecological food web of the great lakes. Clearer waters also allow more sunlight to easily penetrate and warm up the water. This creates the prime conditions for the growth of aquatic vegetation and algal growth causing lakes to overproduce them. [3] They can also damage infrastructures that are near the lakes such as sewer systems and dams which can be very costly to repair.

Methods to Reduce the Damage Done

Once invasive species have established and spread, it can be extremely difficult and costly to control or eradicate them. As a result, the best approach for dealing with invasive species is prevention through monitoring systems to rapidly identify them, and effective mechanisms to destroy them. [5]

The National Wildlife Federation works to attack the problem of invasive species through various methods. They aim to serve as a lead partner in the National Environmental Coalition on Invasive Species, a national partnership that provides a scientific voice on invasive species policy. They are also establishing and strengthening federal policy restricting the importation of potentially damaging plant and animal species. In order to further prevent the introduction of invasive species, they are also advocating for new legislation to require treatment of ballast water in vessels travelling internationally. Another goal is to acquire the restoration funding for the Great Lakes and other major ecosystems to repair the damage caused by existing invasive species.[2]

There are also many steps that an individual can take to prevent the spread of invasive species. Recreational gardeners can conduct research and learn the importance of using native plants and removing invasives through The National Wildlife Federation’s Garden for Wildlife program. One can also ensure that they do not bring a potentially invasive species as a pet into their community. If one already has a foreign species as a pet and they wish to give them away, they should research for places such as a zoo and prevent the organism from escaping into the wild.[4] A good way to avoid the spread of invasive species is to regularly clean your boots, gear, boat, tires, and any other equipment you use outdoors to remove insects and plant parts. In addition, when camping, buy firewood near your campsite (within 30 miles) instead of bringing your own from home. Invertebrates and plants can easily hitch a ride on firewood you haul for camping and you could unknowingly introduce an invasive species to a new area. [1]

Topics for Future Research

  • Asian Carp Prevention

  • Lacey Act Screening Provisions

  • Ballast Water Invasions


[1]Combatting Invasive Species. (n.d.). Retrieved September 04, 2020, from

[2]Invasive Species. (n.d.). Retrieved September 04, 2020, from

[3]Zebra mussel. (n.d.). Retrieved September 04, 2020, from

[4]Henn, C. (2015, November 14). What Happens When People Release Exotic Animals Into the Wild. Retrieved September 04, 2020, from

[5]Rafferty, J. (2019, February 07). Solutions. Retrieved September 04, 2020, from