Introduction to Invasive Species

An Interview with Jeremy Petrusma – Ontario Conservation Coordinator

 By Madison Martinez & Jeremy Petrusma

June 27, 2023

Invasive species removal and management has been a priority for A Rocha Ontario’s conservation efforts for nearly 10 years. At the Cedar Haven Eco-Centre, our team is working hard to address the spread of invasive species. To get a better understanding of the significance of invasive species onsite and in Southern Ontario generally, I connected with our Conservation Coordinator, Jeremy Petrusma, to ask him some questions.

What are invasive species? What are some examples in Ontario?

Invasive species are any organisms like plants, animals, insects, and pathogens that are introduced to an area and cause harm to the environment, economy, or society. We see examples of this in our everyday lives! If you live in the city, many of the little brown birds that you hear chirping and see flying around are invasive House Sparrows. If you live outside the city and have any Ash trees on your property, then you have experienced the impact of the invasive Emerald Ash Borer. Finally, Garlic Mustard is a common invasive plant which takes over and covers the forest floor with a monoculture, reducing our native plant diversity.

What work is A Rocha Ontario doing to address invasive species?

For many years now, we have actively removed and disposed of several invasive species through different methods. For instance, at the Cedar Have Eco-Centre, we hand pull Garlic Mustard at the root before it goes to seed. Similarly, Common Buckthorn (an invasive small tree) is pulled out by the roots using a tool called an extract-a-gator. We also combat invasive Reed Canary Grass that impacts our wetlands by tarping areas and planing native marsh species once the Reed Canary dies. Finally, we remove Curly Pondweed from our pond by using a large razor and rake that cuts the plant and then drags it to the shore. 

What are the main challenges to this work?

The main challenge of this work is the scale. Once an invasive species becomes widespread, it is very difficult to eradicate. Therefore, it is often important to prioritize ecologically sensitive areas or areas that have only recently had an invasive species move into them. 

The second challenge is finding an effective removal technique. Invasive species tend to be hardy and adaptable. This means there are many moments of trial and error as we try to find effective methods of removal. For example, before using extract-a-gators (which remove the roots) on common buckthorn, we had been cutting them with a saw. Unfortunately, the next season we would come across the stumps of cut common buckthorn that had several new stems sprouting and growing leaves. We learned then that in order to fully deal with this plant, the roots needed to be removed. 

Why is this work important? Why is this a priority for A Rocha Ontario’s conservation efforts?

Removing invasive species is important as a first step to take practical action for the health of our ecosystems. We are able to make a direct impact on the ecological health of different areas and plant communities by doing this work. It allows for the native species to thrive in a balanced competition or mutualistic relationships. ARON has the expertise, equipment and resources to make this tangible benefit for the different habitats at Cedar Haven.

Is there anything people can do at home to support the elimination of invasive species?

A great starting point is learning about and being able to identify some invasive species in Ontario. Try to learn their names and look around your yard or park to identify them. If you find some invasive species in your area, learn about effective removal techniques for that particular species. Then, if the methods of removal are low tech and within your capability, start removing them from your property and dispose of them in a safe way. For example, Garlic Mustard can be hand pulled to remove the roots and disposed of in garbage bags to prevent them from spreading the seeds they produce. Information and resources on Garlic Mustard and other invasive species can be found easily at the Invasive Species Centre. 

How can people best support this work?

One way to support our work is to make a donation. This supports our conservation efforts in Ontario and directly supports work like invasive removal and other projects that create habitat for species that are at risk. Another way to support is by volunteering. If you are interested in contributing to invasive removal at the Cedar Haven Eco-Centre, we can train you in identification and removal techniques. Feel free to reach out to on.conservation@arocha.ca to explore more opportunities!