Agriculture and Natural Resources Program

Updated January 1, 2012.

The Invasive Species Specialist Group maintains a Global Invasive Species Database and they have compiled a list of what they consider to be "100 of the Worlds Worst Invasive Species".  The criteria for inclusion in this list are not clear and selection is quite arbitrary. However, I thought it my be informative to count which of these "100 worst invasive species" have established on Guam.  I highlighted species on Guam on the attached PDF. The count stands at 32 out of 100.

Notes

• The most recent arrival on the list is Wasmannia auropunctata, the little fire ant, detected in November, 2011.
• Coptotermes formosanus, the Formosan subterrarean termite, has been reported from Guam.  But recent research indicates that C. gestroi, the Philippines milk termite, is the predominant subterrarean termite on Guam. Researchers believe that previous determinations of C. formosanus were misidentifications, so I have not included this species as being established on Guam.
• Eleutherodactylus coqui, the coqui frog, has been detected on Guam on three separate occasions. However, it has not yet established and is therefor not included in the list.
• Thanks to Brent Tibbats, Guam DOA-DAWR, for his email response which adds an additional two species:  "The rosy wolf snail (Euglandina rosea) was introduced here, and we still find relatively fresh dead shells in the field, and the carp (Cyprinus carpio) is the koi common in hotel and private ponds. we have seen a koi in Fena, and there are reports of them in Agana Springs as well."
• I added feral goats based upon this Guam DOA-DAWR report.