Documentation of the arrival of exotic vascular plants in Yellowstone National Park has been sporadic. An annotated checklist of exotic vascular plants is presented, with information about the approximate arrival time in the park of each species and the current extent of the infestation. Yellowstones flora includes 187 exotic vascular plant species (14.8% of the flora), and the park has an extrapolated mean number of exotic species per 10 km2 of 47.3. The situation in Yellowstone is compared with other areas in North America. The increase in exotics mirrors a corresponding increase in visitation.
Whipple, Jennifer J.
"Annotated checklist of exotic vascular plants in Yellowstone National Park,"
Western North American Naturalist: Vol. 61
, Article 10.
Available at: http://scholarsarchive.byu.edu/wnan/vol61/iss3/10