Invasiveness is difficult to categorize and some locales have their own unique classification schemes. Our basic scheme is based off of the U.S. Executive Order definition and contains 10 classifications (from 1 to 10) in order of decreasing invasiveness.
Rank
Rank Name
Description
0
Unknown
1
Invasive #1
An invasive species or an invasive alien species is defined as a plant, animal or pathogen that is not native to an area, and "whose introduction does or is likely to cause economic or environmental harm or harm to human health." [US Executive Order 13112]
2
Invasive #2
3
Invasive #3
4
Invasive #4
5
Invasive #5
6
Invasive #6
7
Invasive #7
8
Invasive #8
9
Invasive #9
10
Invasive #10
NIISS Noxious Classifications
The degree to which a plant is 'Noxious' is difficult to categorize. Some locales have their own unique classification schemes. Our basic scheme is based off of the Federal Noxious Weed Act and contains 10 classifications (from 1 to 10) in order of decreasing noxious status. For example, a yellow list species might be classified as a #5, whereas a red list species might be a #1 for one U.S. state and an 'A List' species might be a #1, a 'B List' species might be a #5, and a 'C List' species might be a #10 for a different U.S. state.
Rank
Rank Name
Description
0
Unknown
1
Noxious #1
Any living stage (including but not limited to seeds and reproductive parts) of any parasitic or other plant of a kind, or subdivision of a kind, which is of foreign origin, is new to or not widely prevalent in the United States, and can directly or indirectly injure crops, other useful plants, livestock, or poultry or other interests of agriculture, including irrigation, or navigation or the fish and wildlife resources of the United States or the public health (Federal Noxious Weed Act)
2
Noxious #2
3
Noxious #3
4
Noxious #4
5
Noxious #5
6
Noxious #6
7
Noxious #7
8
Noxious #8
9
Noxious #9
10
Noxious #10
NIISS Agricultural Classifications (Cultivated plants and domesticated animals)
Rank
Rank Name
Description
0
Unknown
1
Agricultural
2
Probably Agricultural
3
Probably Not Agricultural
4
Not Agricultural
NIISS Introduced Classifications
Rank
Rank Name
Description
0
Unknown
1
Introduced
An organism that is not indigenous to a given place or area and instead has been accidentally or deliberately transported to this new location by human activity.
2
Probably Introduced
3
Probably Not Introduced
4
Not Introduced
NIISS Native Classifications
Rank
Rank Name
Description
0
Unknown
1
Native
An organism that is within its known historical range and present in an area by natural means
2
Probably Native
3
Probably Non-Native
4
Non-Native
NIISS Rare Classifications
Rank
Rank Name
Description
0
Unknown
1
Rare
Rare refers to a conservation category designating the scarcity of an organism and implying a threat to its viability