The Breakdown on Invasive Species

What are they?

Invasives are species that have either travelled or been transported to an environment outside of their native range. This movement can be purposeful or accidental; however, it differs from that of a non-native or introduced species, and attains invasive status when it begins to outcompete and prevent the growth of native species.

Plants are growing and thriving, so how is this a bad thing? Invasive species management is such an important topic because pollinators, as well as other wildlife and plants, rely on a diverse array of native species to successfully grow and reproduce. Invasive species disrupt an ecosystem's equilibrium, which has developed over thousands of years, causing a decrease in biodiversity that has cascading effects within said ecosystem. The initial invasive species disruption also invites other invasives to thrive in the disturbance, worsening the situation.

Because of the complexities of this, there are various levels of invasive species, as some are more successful than others. Ontario has the most invasive species of all Canada’s provinces and territories, but this is an issue that environments worldwide face. Limited prohibitions and restrictions currently exist for these species, creating a gap between what’s covered by legislation and what's happening on the ground. This leaves organisations, municipalities and conservation authorities to close the gap themselves and take local action.

Invasive species from left to right are European Common Reed (Phragmites australis subsp. australis), Japanese Knotweed (Reyoutria japonica) and Flowering Rush (Butomus umbellatus)

Terrestrial Invasive Species Examples: Phragmites (invasive common reed), Buckthorn (European and glossy), Dog strangling vine (Black and Pale swallow wort), Knotweed (Japanese, giant and hybrid knotweed), Giant hogweed and Wild parsnip, etc.

Aquatic Invasive Species Examples: Xeno-carp, Goldfish, Eurasian watermilfoil, Flowering rush, Curly leaf pond weed, Yellow iris, etc.

There are also invasive insects, fungi and diseases like Emerald ash borer, Spongey moth, Hemlock woolly adelgid, Oak wilt, Butternut canker, Beech bark and leaf disease, etc.

Qualities that make invasive species successful

● Speed: Many invasives grow large, fast and aggressively throughout an elongated season compared to native species 

● Reproduction and dispersal: They are high-volume reproducers that release many eggs or seeds

● High tolerance for various growing conditions, whether that be temperature, pH, pollution, duration of sun/shade, moisture requirements, etc.

● Lack of predators

There are various means by which invasive species spread; some are accidental, and others are purposeful. Accidental spread most commonly occurs via air, water or truck transportation. Despite some restrictions, invasive species move within cargo and boats, or through the water used to balance ships (ballast water). Other accidental means include everyday hiking, wind, wildlife, etc. However, many invasive species have spread through purposeful selling, either in the horticultural/landscaping sphere or the pet/wildlife trade. This remains common today, as restrictions are limited and insufficient to prevent this movement.

What are we doing to mitigate this?

Freshwater Conservation Canada frequently manages invasive species, some of which include Buckthorn, Giant hogweed, and Phragmites. Other species we encounter include Curly leaf pondweed, Garlic mustard, Knotweed and more. Management and removal are done both chemically and manually, over multiple seasons, to ensure success and note the emergence of new growth.

Additional actions include:

● Leading volunteer efforts in invasive removal and educating the public to increase awareness

● Trialling new management methods like biotic resistance, along with our ongoing efforts to reintroduce native species in our restoration projects to increase diversity and support a healthy ecosystem

● Working with other professionals in the space to increase success

FCC staff, volunteers and corporate workday participants are pictured from left to right, showing the removal of Buckthorn, Giant hogweed and Phragmites.

What can the public do to help?

Aside from directly removing invasive species, it's important to raise awareness and encourage people to take proper precautions, when possible, to prevent the spread.

Since personal and recreational boats, canoes and kayaks are concerning vectors, an easy way to prevent this is through proper maintenance and cleaning. Even if you can't see anything, microscopic species or juveniles can still travel this way, which is why it's best practice to clean, drain, and dry your boats and other aquatic equipment between sites. It's even recommended that you take necessary precautions to clean or disinfect your wearable gear (shoes, hiking poles, bags) when moving between regions.

Other options include:

➔ Joining or supporting us in our efforts! Or working with other organisations who have similar missions

➔ Reporting any invasives you see using apps like EDDMapS or iNaturalist

➔ Using native plants in your gardens and landscaping projects

➔ Disposing of garden species and surrendering unwanted pets through proper channels