According to the Michigan Department of Natural Resources, "an invasive species is one that is not native and whose introduction causes harm, or is likely to cause harm to Michigan's economy, environment, or human health." To learn about the State of Michigan's invasive species "Watch List" and ongoing efforts to prevent, control and manage invasive species, visit Michigan Invasive Species.

More often than not, invasive species are introduced either purposefully or inadvertently by people.  Invasive species can have drastic negative impacts on Michigan's economy and ecology. A classic example of this is the accidental introduction of the sea lamprey to the Great Lakes ecosystem. When the Welland Canal was completed and officially connected the Great Lakes to the Atlantic Ocean without natural barriers such as Niagara Falls, the parasitic sea lamprey gained access to the Upper Great Lakes and consequently decimated the naturally occurring lake trout population. 

​Whether animals or plants, invasive species are capable of destroying natural processes due to their rapid reproduction rates and lack of natural predators.  As a result, they degrade wildlife habitat, displace native flora and fauna, and reduce biodiversity. Species such as garlic mustard emit chemicals into the soil that inhibit the growth of other plant species. Some invasive plants, such as giant hogweed or wild parsnip, can cause terrible rashes, burns or even permanent scarring for those that unknowingly touch them. The introduction of zebra and quagga mussels can be more than inconvenience; other than blocking pipes and covering boat motors and docks, these razor sharp mussels can easily cut human skin if unnoticed and accidentally stepped on.