The word “invasive” of course is pejorative, suggesting a threatening, negative, even harmful species. The term refers to plant or animal species that are found in an area that does not usually support such species. The species are introduced to the new area either accidentally (escaping pets) or deliberatively (cats in South Africa to control mice). There are non-native species that are not invasive, including some food crops and even cows in the US that do not cause harm or loss.
Once established, the invasives compete with “native” species. Their presence can harm the environment, human health, or the economy. For instance, invasive species are one of the five major causes of biodiversity loss in Europe; they can cause severe allergies and burns for humans; and, they cause economic damages estimated at EUR 12 billion per year.
rhododendrons, Ireland – The Unpaved Road blog
Within the EU there are Invasive Alien Species Regulations that restrict keeping importing, selling, breeding growing and releasing such species. And eradication can include use of a virus (cats in South Africa), insects, chemicals and even organized hunts (nutria rodents).
Some further ideas to explore on Invasive Species:
Identify an invasive plant or animal species in your area.
How and when did it arrive in your area?
What harm is it causing?
Can it be eradicated? If so, how?
“Invasive alien species,” European Commission bit.ly/3ViNaOy
“Invasive Species,” National Geographic. bit.ly/447y16K
“Invasive & Non-Native Species,” U.S. National Park Service. bit.ly/3AFH3KL