Do You Know the Invasive Plants of Metro Vancouver?

English ivy

Did you know that local governments in the Metro Vancouver region spend over $2 million each year to control 11 invasive species? Humans introduce non-native plant species for different purposes, such as horticulture or ornamental plants. A non-native plant becomes an invasive plant when it dominates an ecosystem and has negative ecological, economic, and human health impacts on communities. Although invasive plants can sometimes provide a benefit to the ecosystem (e.g., the Himalayan blackberry’s fruit – one of the most commonly found invasive plants in Metro Vancouver), these plants also reduce biodiversity and the resilience of ecosystems to disturbances.

Communication and education programs are some of the key approaches used to manage invasive plants in urban greenspaces. These programs engage the public and encourage buy-in of other management approaches. But managers and planners need to understand how much people know about invasive plants in order to tailor their outreach efforts. They also need to have knowledge about their audiences – the people living in their management district – because different demographic groups have different levels of knowledge and perceptions of risk resulting from invasive plants.

Top 5 Invasive Plants in Metro Vancouver

Our research used an online survey to understand people’s knowledge and risk perceptions of five invasive plants in Metro Vancouver:

  1. English ivy
  2. Himalayan blackberry
  3. knotweed
  4. yellow archangel
  5. giant hogweed

We used statistical models to examine how different demographic groups perceive these plants in terms of ecological, economic, and human health risks. In addition, we investigated at which levels Metro Vancouverites support existing local invasive plant management activities.

Himalayan blackberry, an invasive species
Himalayan blackberry

We received 356 survey responses from across Metro Vancouver. Our results showed that respondents were well informed about the ecological risks of invasive plants on the native ecosystem. However, they tended to underestimate or be unaware of the economic and human health risks. Older and/or higher income (annual income over $50,000) respondents perceived higher risk of these plants; respondents affiliated with professional/recreational groups perceived higher economic risks compared to others. Respondents supported local governments funding active management activities such as community invasive plant pulls that citizens can get directly involved in.

How Can This Study Improve Outreach Programs?

Managers, planners, and communicators can use these findings on people’s knowledge and risk perceptions of invasive plants to emphasize the economic and human health impacts of these plants when they develop future outreach programs. Knowing that people support active management strategies will help planners to select the type of outreach and stewardship activities that align with these preferences. Leveraging existing knowledge and support of people on this conservation issue can help create more effective outreach programs and educational resources to effectively manage invasive plants in urban greenspaces.

Nguyet-Anh Nguyen is a former graduate student with the Forest Biometrics Lab, co-supervised by Drs Bianca Eskelson and Michael Meitner. For more information about this topic contact Nguyet-Anh Nguyen at

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