What Invasive Species Reveal About Public Engagement With Local Ecosystems

Invisible environmental hazards like wild parsnip and invasive pampas grass trigger severe chemical burns and chronic allergies, driving a push for localized community stewardship.

• By Irina Fitzgerald
• June 23, 2026

They are green, and yes, they can genuinely be dangerous.

Once introduced to foreign ecosystems, they push native species out of their habitats, compete for resources and take over space. And this story is about the aliens from our planet, but different territories: the invasive plants.

When non-native plants arrive in a new environment, the natural checks and balances that controlled them back home often disappear. Local pests do not feed on them. Native diseases do not affect them. Their seeds spread easily - by wind, insects, animals and very often by us: on shoes, clothing, bicycle tires and gardening equipment. Some species create problems not only for local ecosystems, but also for the very people who introduced them.

Take wild parsnip, for example. A walk past dense stands of it on a hot summer day can leave you with painful chemical burns when sunlight reacts with the plant’s sap. These patches can appear even along popular recreational trails, including Ottawa-area routes such as the scenic Klondike Trail in Kanata North. Warning signs are posted there for a reason: this is not merely a non-native plant; it is a recognized invasive species. It also carries a significant economic impact, with Ontario’s annual expenditures related to wild parsnip estimated at approximately $1.08 million.

Not All The Aliens Are Equally Harmful

To be fair, not every introduced plant becomes destructive. Some non-native species remain harmless in their new environments and survive only with human care. Others escape gardens and quietly integrate into local ecosystems without causing serious disruption. But invasive species are different. They spread aggressively, often like wildfire, forming colonies that overwhelm both disturbed and natural habitats. They out compete native plants, rapidly reshape ecosystems and alter the balance of entire landscapes.

And for ordinary people, it is often almost impossible to predict which ornamental plant will remain well-behaved and which one will eventually become an ecological problem. Plants may be able to spread away from invasions. Humans, however, cannot simply relocate their daily lives so easily.

People end up fighting not only invasive species, but sometimes their own immune systems as well: managing allergies or asthma. This connection is still rarely discussed publicly, yet scientific research increasingly points to links between invasive plants, urbanization and rising allergen exposure. Some invasive species are highly allergenic themselves. Others can extend allergy seasons, intensify airborne pollen exposure or even increase the allergenic properties of surrounding vegetation or people’s sensitization to allergies.

Let’s imagine hypothetical situation: you have never had allergies before. Then you decide to improve your landscaping and plant elegant Pampas grass (Cortaderia selloana) in your yard. Several years later, every allergy season leaves you dependent on antihistamines that affect concentration, energy or cognitive clarity. How quickly would you suspect that the beautiful ornamental grass in your own backyard, or your neighbour’s backyard, might be contributing to the problem? Probably never. And even if you did suspect it, would you believe it is the reason?

To be fair, when people are searching for explanations for chronic symptoms, they are often willing to believe almost anything if it offers hope of finding a cause.

Fortunately, there is no need to rely on myths or internet folklore. Scientific research, municipal advisories, invasive species regulations and even airline biosecurity rules already provide enough evidence that governments take these risks seriously - usually because real ecological or public health damage has already occurred.

What Can You Do If You Do Not Want To Ignore The Problem?

If you want to support local ecosystems and possibly make life easier for allergy sufferers as well, one of the simplest things you can do is choose native plants for your garden. Even better: consider planting species that are locally threatened or endangered. Small choices at the household level can collectively make a significant ecological difference.

Garden centers across Canada sell both native and imported plants, although identifying truly native species can still require asking knowledgeable staff or doing independent research. Officially prohibited invasive species cannot legally be imported or sold in Canada. Canadians can also learn more about invasive plants through organizations such as the Canadian Coalition for Invasive Plant Regulation.

Preventing the spread of invasive species can also be surprisingly simple: clean your shoe soles, bicycle tires and outdoor gear before and after visiting natural areas.

And if you want to go further than maintaining your own garden, many volunteer groups work every year to contain existing invasions using one of the few environmentally responsible and effective approaches currently available: containment and damage reduction. In practice, this often means cutting or removing invasive plants before they go to seed - essentially the same strategy generations of gardeners have used against weeds.

Is that enough? Not entirely.

Long-term ecological recovery also requires restoring competition from native plants after invasive species are removed. Otherwise, cleared spaces are often quickly colonized by the same invasive species again. That is why restoration projects are usually safest and most effective when coordinated through specialized environmental organizations.

Why Work With Organized Volunteer Groups?

First, identifying invasive species is harder than many people assume. Plants change dramatically throughout their life cycles, and even volunteers sometimes struggle to distinguish invasive plants from visually similar native species. During my own volunteer work, I realized how easily the brain starts “seeing” the target species everywhere once you spend hours scanning through dense vegetation. What looks more obvious on the photographs below becomes much less obvious in the field.

Still, for people who enjoy observational challenges, the ecological equivalent of “spot the difference” puzzles at work can actually become surprisingly engaging. Others enjoy the meditative rhythm of repetitive fieldwork: digging, cutting, clearing. Some appreciate the social side - conversations with volunteers from different backgrounds, opportunities to practice language skills or simply the shared feeling of contributing to something tangible and meaningful. And honestly, that sense of higher purpose feels good.

Second, most land belongs to someone. Unauthorized removal of vegetation on public or private property can create legal and ecological problems. Specialized organizations coordinate permissions, ecological assessments and land access, reducing risks for volunteers and helping avoid accidental ecosystem damage.

Third, some invasive species require more hazardous control methods that involve professional training, regulatory approval or chemical treatment. These situations should never be handled casually.

Local Stewardship In Action

In that respect, Ottawa residents are fortunate. The Ottawa Stewardship Council supports environmental projects across the region in an advisory capacity and also runs its own initiative, Kanata North Regeneration Stewards initiative, where I had the opportunity to volunteer. Before that experience, I honestly did not realize that ordinary people could meaningfully participate in controlling invasive plant species, or that the work itself could be genuinely rewarding.