RESOURCES

What can be done once an invasive species establishes a population in a new waterbody? ​It depends on the species and the size of the population that has been found. Invasive plant species can often be controlled through physical removal, carefully timed mowing of that area, biocontrols, or prescribed burning of the landscape. Spot treating cut stumps or woody stems with a chemical control is often very effective in removing terrestrial invasive shrubs and trees. Sometimes areas where the invasive plants are found are hard to reach (think wetlands or waterbodies) and chemical controls may be considered. Using a chemical control is very dependent on the surrounding native vegetation and any potential risk of water contamination. You need a license to apply chemical controls in wet areas. Often biocontrols, like releasing cella beetles to control invasive Purple Loosestrife, are the safest option. Invasive animal species removal is very dependent on the species and the size of the population. The smaller the population, the better the likelihood that it can be removed. If only one rusty crayfish is found and removed (perhaps it was used as bait by someone uninformed about its invasive status and survived) then you may have just prevented the spread of rusty crayfish to that area. ​Some species are impossible to totally remove. Good examples of this are zebra mussels, New Zealand mudsnails, and Asian clams. Their eggs are often microscopic, number in the thousands, and can tolerate being dried out for a month at a time. NZ mudsnails can also reproduce asexually, so it only takes one snail to start a population. In these cases careful cleaning and decontamination of any equipment that has been in contact with the water, mud, or plants from locations known to have these invasive species is the best way to slow their spread. Close monitoring of these types of invasive species can help us find ways to slow their spread and allow native species the time they need to adapt to the invasive species presence.