Invasive Species 101

It’s Invasive Species Awareness Week (ISAW)! ISAW takes place each year during the last week of February to raise awareness about invasive species. What is an invasive species? Why are they bad? How can we manage them? This is your Invasive Species 101!

What are invasive species?

  • Plants, animals, and pathogens (disease spreaders) that fit two criteria:
    • They are not native to the areas where we live, but were introduced to the area by human activities.
    • They are able to either dominate areas where they get established, spread long distances very easily, or most often both.


How do invasive species affect the forests/meadows/wetlands that surround us?

  • Out-competing native species
    • Where invasive plants, animals, and pathogens thrive, native plant and wildlife populations lose their habitat and struggle to survive.
  • Creating mono-cultures and reducing biodiversity
    • Invasive species often establish large areas where they are the only thing that can live there. This reduces biodiversity, exposing the natural environment to damage and disease.
  • Difficult to remove once growing or occurring
    • Once an invasive species becomes established it can be extremely difficult, and often impossible, to fully remove. By their nature, invasive species are very hardy and sustained effort is needed for management year after year.


Why is invasive species management important?

Controlling the spread of invasive species has a long list of benefits, including ecological, economical, cultural, and human health related. These benefits include:

  • Restoring biodiversity to a degraded area.
  • Increasing ecosystem strength to survive other harmful things like climate change.
  • Maintaining usability of natural areas on both public and private property.
  • Avoiding high costs of damage to the agriculture, forestry, and fisheries industries.
  • Maintaining the safety of infrastructure, for example, solving the problem of zebra mussels blocking drinking water intake pipes.
  • Keeping everyone safe by removing invasive plants that can harm humans, like Giant Hogweed for example .


What invasive species might you have near you?

Invasive species are widespread throughout the Hamilton watershed and live in many different areas. However, you might have some very close to home. Many gardens are planted with non-native, invasive groundcover plants. These plants are popular in the garden because they’re very hardy, grow to fill a garden on their own, and can fit in anywhere. Those characteristics make gardening easy, but they’re also the same qualities that make these plants invasive.

Here are some examples of common invasive garden groundcover plants:

What can you do?

Stay tuned to our blog because we will have more Invasive Species Awareness Week posts coming up! We’ll be talking all week about what you can do to get involved with keeping our watershed healthy by managing invasive species. Until then, look in your garden to see if you have any of these three common groundcover invasives, and take them out! Check the additional resources section below to see great alternatives to grow instead.


Additional Resources


Photo sources
English Ivy:


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