An Assessment of Exotic Plant Species of Rocky Mountain National Park

The invasion of exotic plants is becoming a problem in many ecosystems
including some areas in Rocky Mountain National Park (RMNP) (Rocky Mountain
National Park Resource Management Reports #1 and #13). Some exotic species,
such as leafy spurge and spotted knapweed, are capable of rapidly colonizing
areas, altering community composition, and even displacing native species
(Belcher and Wilson 1989, Tyser and Key 1988). In many cases, the processes of
invasion are poorly documented, and little information is available on an
area's past history. However, there is a large amount of information available
in the literature which relates to the life history traits of exotic species
and the distribution of exotic species. This information can be used to help
predict the potential distribution and threat of exotic species to ecosystems.
Exotic plants can be thought of as those plants which did not originally occur
in the ecosystem, and have since been introduced to the area. The National Park
Service (NPS) defines an exotic species as, "those that occur in a given place
as a result of direct or indirect, deliberate, or accidental actions by
humans." This somewhat conservative definition of exotic species is necessary
to insure that natural resources in national parks are preserved. NPS policy
generally prohibits the introduction of exotic species into natural areas of
national parks. Exotic species which threaten park resources or public health
are to be managed or eliminated if possible. In addition, the NPS recently
signed a memorandum of understanding with 10 other federal and state agencies
in the state of Colorado. This agreement states that all paid management
agencies will work with private and county entities to manage exotic plants
and, in particular, "noxious weeds." RMNP is currently working with Estes Park
in exotic plant control as part of this agreement.