Why we should be concerned about invasive species on Lake Weslemkoon?
Invasive species are plants, animals, and micro-organisms introduced by human action outside their natural past or present distribution whose introduction or spread threatens the environment, the economy, or society, including human health (Government of Canada, 2004). It is important to be educated and aware of invasive species in our area and the surrounding areas, as they are most likely to spread by human movement; accidentally or intentionally. Once invasive species are introduced, it is extremely difficult to remove them effectively. As cottagers and homeowners on Lake Weslemkoon, invasive species pose threats to the natural lake environment that we all love to enjoy! In order to avoid the introduction and spread of invasive species on our lake, the first step is to be educated. This page is intended to cover some of the most common and likely to spread invasive species in our area, by providing identification information, reporting and best management practices.
Invasive Phragmites is a perennial grass that grows very aggressively, out competing the surrounding native plants for water and nutrients. Phragmites releases toxins from its roots into the surrounding soil, hindering the growth of other plants and killing them. Phragmites prefer areas of standing water, but their massive roots allow them to survive in relatively dry areas, invasive Phragmites can grow up to 5 metres tall!
· Out competes native plants
· Grows and spreads rapidly, using up water resources for other plants
· Provides extremely poor habitat and food for other species
· Can pose fire hazards due to dead standing stalks
· Hinders recreational activities such as boating, swimming and angling
How to Identify Invasive Phragmites:
Identifying invasive Phragmites can be difficult, as the native species of Phragmites is very close in appearance. Native Phragmites does not grow as densely, or tall and has much more sparse seed heads than the invasive species.
· Grows in dense stands (200 stems per square metre)
· Can reach heights of 5 metres
· Has stems that are tan/beige with blue-green leaves and dense seed heads
Zebra Mussels are a well-known invasive species in Ontario. They are a freshwater bivalve that is native to Eurasia and have entered Ontario through ocean ships. They can rapidly inhabit hard and soft surfaces like docks, boats, and beaches. Zebra mussels are a harmful invasive species due to their ability to alter the aquatic food web by removing important food sources like plankton. By doing this, lake water becomes clearer allowing more sunlight to penetrate and increase aquatic plant growth.
· Alter food webs impacting aquatic species, like fish and aquatic birds
· Increase aquatic plant growth, increase of toxic algae blooms
· Dangerous to human health due to their sharp edges which can cut swimmers
How to Identify Zebra Mussels:
· 2-2.5 cm in length, can grow up to 4 cm
· Sits flat on its underside
· Triangle shaped
· Zig-zag pattern, black/brown with white in colour
· Colour patterns can vary
Eurasian water-milfoil is a fast growing perennial that typically grows in shallow water but can grow in water up to 10 metres deep. This plant forms dense mats that can quickly spread by interbreeding with native milfoil plants. Water currents, boats and anglers can easily spread this plant to new areas without even realizing, since very small fragments of Eurasian water-milfoil can root and develop new plants. When the dense mats of Eurasian water-milfoil start to die off in the fall, the decaying plant can reduce the available oxygen levels in the water which primarily impacts fish species.
· Forms dense, quickly spreading mats that out compete with native species
· Decaying plant uses large amounts of oxygen in the water, killing off fish
· Hinders recreational activities such as swimming, boating and angling
How to Identify Eurasian water-milfoil:
· Grows under the waters surface
· Has feather-like leaves than circle the main stem in groups of 4 or 5
· Leaves have 12 or more thread-like segments
· Small reddish flowers bloom above the surface of the water in late July, early August about 5-20 cm tall
Eurasian water-milfoil looks very similar to the native plant Northern water-milfoil, the main difference being Northern water-milfoil only has 11 or fewer thread-like segments on each leaf.
Giant hogweed is a perennial plant from the carrot family that was introduced to southern and central Ontario as a garden ornamental from southwest Asia. In ideal conditions, this plant can grow up to 5.5 metres tall in roadside, ditches, and streams. This plant poses serious human health risks as the toxins it produces can cause dermatitis and can result in severe burns if the sap is on the skin and exposed to sunlight. Symptoms typically occur within 48 hours and result in blisters, burns and purple scarring that can last for years. In the event of direct exposure to Giant hogweed, wash the affected area with soap and water. Keep the affected area out of sunlight, if dermatitis occurs, see a doctor. If Giant hogweed is exposed to your eyes immediately flush the eyes and see a doctor.
Giant hogweed is a dangerous plant. It is important to seek professional help for management and removal if you locate Giant hogweed on your property. Please see the following link for more information: https://docs.ontario.ca/documents/3244/giant-hogweed-fact-sheet.pdf
How to Identify Giant hogweed:
· First year the plant produces a rosette up to one metre tall
· 2-5 years the plant produces flowers and begins to grow upwards
· Large hollow stem, large lobed leaves
· Stem covered in reddish-purple flecks and stiff hairs filled with sap
· Flowers once in its lifetime, produces up to 120,000 winged seeds
· Seeds can travel 10 metres by wind, and float in streams for 3 days
Giant hogweed looks similar to both non-native Queen Anne’s lace and native Cow parsnip.
Similar to Giant hogweed, and a member of the carrot family, Wild parsnip grows in dense stands and can establish well in disturbed environments such as waste dumps, abandoned areas, open fields and meadows. Wild parsnip outcompetes native plants and reduces biodiversity. Wild parsnip sap can also cause serve burns when exposed to the sunlight. In the event of direct exposure to Wild parsnip, wash the affected area with soap and water. Keep the affected area out of sunlight, if dermatitis occurs, see a doctor. If Wild parsnip is exposed to your eyes immediately flush the eyes and see a doctor.
For smaller infestations of Wild parsnip on your property (fewer than 100 plants), removal on your own may be possible with protective clothing and proper disposal of plants. For more information on the removal of Wild parsnip see the following link: https://docs.ontario.ca/documents/3249/stdprod-109232.pdf
How to identify Wild parsnip:
Like Giant hogweed, Wild parsnip grows in a low rosette for the first year. In the second year it grows upwards on a tall stalk and flowers, then dies off.
· Grows up to 1.5 metres tall
· The single green stem is 2-5 cm thick and smooth with few hairs
· Compound leaves arranged in pairs, sharply toothed leaflets that are shaped like a mitten
· Yellowish-green flowers form umbrella-shaped clusters 10 to 20 cm across
Best Management Practices/Reporting:
If you believe you have come across an invasive species, report it! Reporting allows for organizations like Ontario’s Invading Species Awareness Program, Invasive Species Council, and others, who actively track and manage invasive species know that it has been spotted in Lake Weslemkoon. Reporting can be done directly through your smartphone through EDDMapS (https://www.eddmaps.org/Ontario/), or by calling Ontario’s Federation of Anglers and Hunters Invading Species Hotline at 1-800-563-7711. There is limited data for distribution of invasive species in and around Lake Weslemkoon so it is important to report species when they are located.
Some invasive species can be managed on your own, although it is essential to consult Ontario’s Best Management Practices before attempting removal and management on your own. For more information on how to manage invasive species visit: https://www.ontarioinvasiveplants.ca/resources/best-management-practices/
Additional Resources and Information:
*there are action plans for anglers, cottagers, boaters and hikers on this link