Milfoil foiled again
Eurasian water milfoil (Myriophyllum spicatum) in the Desbarats River, near Sault Ste Marie, Ontario (Photo by Fungus Guy / Wikimedia Commons)
After 3 years of study, Wildsight’s Columbia Headwaters Invasive Plant Species Program, supported by Columbia Basin Trust and the Columbia Wetlands Stewardship Partners, is happy to report that “…there are no foreign aquatic plants in Lake Windermere.”
The lake has been given a clean bill of health; researchers were looking in particular for signs of the dreaded Eurasian water milfoil, notorious across North America for its ability to choke out aquatic habitat, costing governments millions of dollars to control.
While aquatic plants play an important role in the biology of our lakes, providing food, habitat and rearing areas for a wide variety of organisms, some plants such as the Eurasian water milfoil can wreak havoc by:
- growing and spreading rapidly
- invading and replacing native plant communities
- obstructing swimming, boating, waterskiing and fishing
- littering beaches with plant debris
- impeding flood control, water conservation, drainage and irrigation works
- reducing tourism where dense growth limits recreation
The first sighting of Eurasian water milfoil in British Columbia was in 1970 in Lake Okanagan and the plant has since spread to lakes in the Shuswap, the Kootenays and on Vancouver Island. It grows from a fibrous root system and although it spreads along the bottom of the bodies of water, it can reach more than 5m in length, floating along the water surfaces.
Wildsight began sampling aquatic plants in the area two years ago after residents approached the organization with concerns about weeds in and around the lake. The latest round of tests took place in early September of this year when Rachel Darvill, Columbia Headwaters Program Manager, and her team sampled plants around 10 Lake Windermere boat docks and two Columbia Lake docks. A healthy diversity of plants was found, including the native species of milfoil that appears identical to the invasive Eurasian type. Samples were sent to a lab in Michigan which used DNA analysis to determine that the species in both lakes is a native northern variety.
A high level of boating activity can lead to an infestation of Eurasian water milfoil. Ms. Darvill explains that because it is a robust plant that can multiply from its pieces, not just its seeds, “…any bit of milfoil on a boat, a pair of waders, a floatplane, a wake board — any bit of invasive milfoil that survives from one waterway into our waterways — can start a colony.”
She further says she thinks the reason why Lake Windermere has escaped infestation thus far may be that many of Lake Windermere’s boats stay put all year long, not going into new waterways where they might pick up weeds and bring them back.
Ms. Darvill believes that prevention is the key to keeping our lakes free of Eurasian water milfoil. Signs will go up next spring, reminding boaters who are new to the area to make sure their boats and clothing such as fishing gear and gumboots are clean and dry before entering a new body of water.
For further information about the program, please contact: Rachel Darvill, Columbia Headwaters Program Manager at 250-344-4961 or rachel@wildsight.ca
Good information about the uses and benefits of aquatic plants to the natural ecosystem can be found at http://www.ecy.wa.gov/programs/wq/plants/native/uses.html
For more information about Wildsight, visit http://www.wildsight.ca
