In natural ecosystems, invasive plants displace or destroy native plant populations.
Many rare and endangered native plants are also at risk from extinction from non-native plant invasion.
By removing the natural wildlife, invasive plants also reduce wildlife habitat.
Aquatic & Riparian
Shallow root systems can increase erosion, causing higher surface runoff, which increases stream sediment and reduces water quality.
Riparian invasive plants often grow in dense monocultures, resulting in negative impacts to nesting, cover and breeding habitat for fish and wildlife.
Infestations can change wetland structure by trapping sediments, creating higher, drier land that favours tree and shrub species rather than wetland species.
Agriculture
Invasive plants outcompete with existing forage and are often unpalatable to livestock, reducing overall levels of grazing.
They also compete with agricultural crops and reduce overall crop yield and quality.
Invasive plants require costly, long-term strategies to control and manage their spread.
Forestry
Dense infestations of weeds increase the risk of wildfire because they are a source of fuel as they mature.
Noxious weed infestations compete with new tree seedlings for soil nutrients, light and moisture. This results in increased costs for silviculture.
Recreation
Invasive plants degrade the natural beauty biodiversity of the landscapes.
Invasive plants can limit access for recreationalists (i.e. gorse and Himalayan blackberry).
Health & Safety
Some invasive plants are toxic, can cause skin and respiratory irritations (i.e. giant hogweed and daphne).
Some invasive plants cause seasonal allergies and hay fever (i.e. Scotch broom).
Some invasive plants can be toxic to horses and livestock (i.e. tansy ragwort).
