Municipalities looking for tools to combat invasive plants in herbicide-free areas may now have an effective option to consider for future management programs—foraging goats. A pilot project to battle invasive knotweeds using foraging goats began in Courtenay last summer, and is now entering its second season. Millard/Piercy Watershed Stewards has partnered with the Comox Valley Farmers’ Institute and the Shamrock 4H Oddstock and Craft Club to run the program and engage youth in the foraging schedule. Last summer, a small herd of 20 goats significantly reduced the energy stores of the invasive knotweeds at the test site by more than half of their size. Projections for this season look just as promising. The aim is that goats foraging on the leaves and shoots will dramatically decrease the energy of the roots, to slow or eventually halt the growth of the knotweeds.
According to Millard/Piercy Watershed Stewards’ Watershed Coordinator, Ronna-Rae Leonard, one of the key advantages to using goats is how gentle they are in their foraging. Many invasive plants, such as invasive knotweeds, spread vigorously when their root systems are disturbed and broken; however, goats leave the roots untouched.
Invasive knotweeds are some of the most potentially damaging invasive plants to riparian systems, said Jeff Hallworth, Agrologist and Coastal Invasive Plant Specialist for the Ministry of Forests and Range. “The biodiversity of native flora, salmon populations, and water quality are all potentially threatened by this most formidable of invasive alien plants.”
Knotweeds threaten biodiversity by reducing available habitat and increasing soil erosion. Without any natural enemies, knotweeds quickly dominate freshly disturbed soil in roadside ditches, low-lying areas, irrigation canals, and other water drainage systems. Knotweeds can reduce or eliminate access to water bodies for recreational activities including fishing, swimming, boating, canoeing, and kayaking. Stream banks are at particular risk as exposed roots break off and float downstream to form new infestations. Riparian areas are herbicide-free zones, making the use of goats a potentially effective alternative.
Although foraging goats will not completely eradicate an infestation, they are proving a cost-effective control option for managing invasive plants with the added benefit of providing economic benefits to local farmers.
A similar two-year pilot project using goats to battle invasive plants like orange hawkweed (Hieracium aurantiacum), dandelion (Taraxacum Officinale), Canada thistle (Cirsium arvense), and horsetail (Equisetum arvense) was completed in Prince George last year, run by environmental studies professor, Annie Booth, at the University of Northern British Columbia. This two-year study determined that goats can make as much of a difference reducing the energy stores of an infestation as herbicides, with a much lower cost.
The results of both pilot projects have proved positive for the use of goats as an alternative control method, though only in certain conditions since, being grazers, goats will eat everything in their site, including flowers and shrubs.
