The definition of an invasive species is ‘a non-native organism which causes environmental, social, or economic harm.’ But what does ‘harm’ look like? Well, the answers range from increased fire risk and erosion to habitat loss and infrastructure damage.
Top of mind at this time of year is the increased fire risk. This can happen in a few different ways. Some invasives are, by nature, more highly flammable. Scotch broom (Cytisus scoparius) for example, is rich with natural oils, increasing the risk and intensity of wildfire in infested sites. Because invasive plants are not often palatable to grazers and browsers and lack predators and disease that keep native species in check, they often grow in dense patches. This adds to fuel on the ground and can create fuel ladders that boost flames into Scotch broom (Cytisus scoparius)
the forest crown. As we have witnessed repeatedly, wildfires are devastating on multiple fronts: people are displaced, homes and infrastructure destroyed, and some of our most beautiful landscapes scarred. Managing the invasive species in our community is one more way to reduce the risk to our homes.
On the opposite end of the spectrum, invasive species also create issues during extreme rain events. Without the stabilizing root systems of native plants, areas infested with invasives can experience an increase in erosion which caries away topsoil and destabilizes slopes. Aquatic invasive plants can dry out wetlands, or choke narrow waterways, increasing the risk of flooding. Knotweed species (an ornamental species called bamboo in some gardening communities) have been the poster child for invasives taking over around lakes and along riverbanks and creeks. Not only do they outcompete native vegetation, but their roots can penetrate foundations. Aquatic invasives disrupt delicate ecosystems and put people and places downstream at risk.
Saltcedar (Tamarix spp) - a thirsty invasive tree which can cause significant
damage in wetlands
Invasive species are the second largest threat to biodiversity worldwide next to habitat loss. Where invasive species are present, native vegetation used for food and shelter by the local wildlife is lost. Invasives complete for resources without the restraints of predators and disease that burden native plant species. In addition, most invasive plants are not particularly palatable or nutritious so invaded sites can have vastly reduced capacity for supporting diverse life.
Though the invasive species already present are damaging enough to cause concern, they also open doors for even more pests to establish. Both invasive plants and animals can harbour disease and other pests that could be potentially devastating for ecosystems or agriculture crops. For example, tree of heaven (Ailanthus altissima) is a host for the spotted lanternfly (Lycorma delicatula). If the spotted lanternfly were to establish in BC there is potential for huge losses in orchards and vineyards. According to the Invasive Species Centre, the spotted lanternfly has caused millions of dollars worth of damage to the agriculture industry in Pennsylvania. Working to get rid of tree of heaven will prevent larger problems down the road.
Treen of heaven (Ailanthus altissima) - seeds
Treen of heaven (Ailanthus altissima)
Seen or unseen, invasive species have an impact on all of us, from major environmental and economic losses to the degradation of our favourite recreation areas to burs caught in our socks after a walk. The good news is that we, as a community, can mitigate these impacts:
Clean, drain, and dry your boats and aquatic gear.
Remove dirt and seeds from your shoes, clothing, and pets after outdoor activities.
Stay on designates roads and trails.
Safely remove, bag, and dispose of invasive plants.
Don’t let pets loose in the wild.
Report invasive species to Boundary Invasive Species Society at info@boundaryinvasives.com or (250) 446-2232.
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