Species deemed as "Early Detection" are defined as being exotic, invasive   species which fit any of the following descriptions:

1. Newly established in Pennsylvania.  

 2. Thought to be in Pennsylvania but not well documented. 

3. Not found in Pennsylvania but expected to arrive and considered moderately invasive.

Alligator-weed
Alligator-weed

Alternanthera philoxeroides Photo credit: Melissa McMasters/Flickr

Red swamp crayfish
Red swamp crayfish

Procambarus clarkii Photo credit: © Ted van den Bergh/Flickr

Marsh thistle
Marsh thistle

Cirsium palustre Photo credit: © Rea Brinkhoff/Flickr

Giant snakehead
Giant snakehead

Channa micropeltes Photo credit: JW/Flickr

Early Detection Species

Species Profiles

 View photos and profiles for many of the species listed in this category.

Not present: Species not yet found in Pennsylvania.

Uncommon: Species found in Pennsylvania, but still very rare.

Found only in its PA native range: This species is native to parts of Pennsylvania; if found in other parts of the state, it may be suspected of being an invasive species.

*Status column last updated in April 2019.