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Invasive Species Pulls

June 2023

HNP Ontario hosted two brand new invasive species pull events in 2023! We collaborated with two other organizations, Toronto Nature Stewards and Credit Valley Conservation, to provide volunteering opportunities within the GTA by removing invasive garlic mustard plants from ecosystems.

What are Invasive Species?

  • Invasive species are non-native organisms that are introduced to a new ecosystem.

  • Since they do not have natural predators, they multiply rapidly and can cause harm to parts of the ecosystem, ultimately even becoming issues for humans.

  • Invasive species are often purposefully/accidentally released through human activities, such as pest control.

  • Non-native species are only invasive if their introduction causes harm.

How are they harmful to the environment?

  • Invasive Species outcompete native species for food and resources, which disrupts the food web and may eventually lead to the extinction of native species.

  • Many invasive destroy habitats by overconsuming natural resources, including plants.

  • This reduces biodiversity in an ecosystem, which is essential to support all life on Earth.

Why should you care?

  • While it may seem like invasive species only have harmful consequences on the environment, these impacts ultimately affect humans as well.

  • The introduction of invasive species exposes new diseases that are threats to human health, like the West Nile virus.

  • Loss of biodiversity and habitats weakens humans' connection with the environment and may threaten our own habitats as well.

  • Economic impacts include decreased agricultural crop yields, a declined fishing industry, clogged waterways, and limited recreational opportunities, such as camping. We would need to spend more money on control, removal and prevention efforts.

Garlic Mustard

Garlic mustard is a plant originating from Europe, introduced for medicinal purposes and food. Garlic mustard is an invasive, non-native herb that spreads by seed.  Garlic mustard is a threat to the biodiversity of many native ecosystems in Ontario. It forms dense patches on forest floors which dominate and displace native wildflowers, tree seedlings, and other native plant species of intact forests. Garlic mustard grows in a wide range of habitats making it difficult to contain as it spreads quickly along roadsides, trails, and fence lines. Garlic Mustard plant stands can produce more than 62,000 seeds per square meter to quickly out compete local flora, changing the structure of plant communities all throughout Ontario. This plant releases chemicals within the soil, further preventing the growth of other plants and grasses. 

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Common Buckthorn

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What you can do:

  • Learn how to identify common buckthorn and other invasive plants

  • Avoid in landscaping and gardens

  • Dispose of buckthorn in garbage, NOT compost 

  • Prevent spread of the plant when hiking by staying on trails and keeping pets on a leash

How is it invasive?

  • Can thrive in a wide range of soils and weather conditions (can live in many different habitats)

  • Easily spreads by birds and other animals that eat its fruit

  • Grows in dense groups and therefore shades other native plants from the sun, not allowing them to grow

  • Alter Nitrogen levels in the soil, which benefits its own growth, but harms native plants.

  • Germinate quickly and produce a large number of seeds

Meet Finnbarr O'Callahan

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From Toronto  Nature Stewards

Finnbarr O'Callahan is a lead steward at Toronto Nature Stewards, a non-profit that aims to engage the people of Toronto in the stewardship of natural areas. Finnbarr volunteered at the nearby Roxborough Parkette last summer, and is excited to be working with other passionate volunteers to make Severn Creek even more welcoming for local wildlife and visitors!

Severn Creek Park

Severn Creek Park is a new stewardship site for 2023 and is the most downtown of all sites that the Toronto Nature Stewards (TNS) will volunteer at! The park features a sunny grass lawn nestled between wooded slopes on either side, and the two trails running through the park are enjoyed by walkers year-round.

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Meet Keren Bromberg

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From Credit Valley Conservation

Keren Bromberg is a senior coordinator at Credit Valley Conservation, a community-based environmental organization, dedicated to protecting, restoring, and managing the natural resources of the Credit River Watershed.

Rattray Marsh Conservation Area

The Rattray Marsh Conservation Area is one of the few remaining wetlands in the GTA, specifically Mississauga, that the Credit Valley Conservation (CVC) operates!

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How Can We Help?

  • Learning how to identify garlic mustard and other invasive plants is an effective strategy to manage these species, if they are found on your property

  • Avoid using invasive plants in gardens and landscaping.

  • Buy native or non-invasive plants from reputable garden suppliers. Native plants provide habitat and food sources for native wildlife.

  • Dispose of invasive plants in the garbage. Do not put them in the compost or discard them in natural areas as the discarded flowers may produce seeds.

  • When hiking, prevent the spread of invasive plants by staying on trails and keeping pets on a leash.

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