What is an Invasive Species?
FONTT uses the definition of invasive species established for the U.S. federal government, which reads as follows:
“Invasive species” means an alien species whose introduction does or is likely to cause economic or environmental harm or harm to human health.
Executive Order 13112
signed by President Clinton
February 3, 1999
For general information on this definition, read What are Invasive Species? on the USDA National Invasive Species Council website.
Related Terms
Native species = has evolved in a given place over a period of time sufficient to develop complex and essential relationships with the physical environment and other organisms in a given ecological community (Darke and Tallamy, see “Native Tree” Defined)
Non-native species = not native (i.e., alien) to the ecosystem under consideration
Invasive species = non-native (or alien) to the ecosystem under consideration and whose introduction causes or is likely to cause economic or environmental harm or harm to human health (emphasis added to the U.S. federal definition).
Click to watch a 4-minute video on the definitions of “native,” “non-native,” and “invasives.”
Are all non-natives invasive?
No, all non-native species are not invasive. However, by definition, all invasive species are non-native.
Friends of Native Trees in Takoma 