management of invasive plant species takes an integrated approach
incorporating the following steps:
For a state
the size of Alaska, field surveys for invasive plants are critical
for detecting infestations before they get out of control. Rather
than randomly surveying for invasive plants, areas are prioritized
according to the amount of human access and use that has occurred
there in the past. Global positioning system (GPS)
units enable the Alaska EPMT to mark an infestation once found, so
that its location is recorded for the future.
Controlling invasive plants poses a special dilemma
because once an infestation is identified it is often already so
large that containment is not only difficult, but also expensive. In
Alaska parklands, a special emphasis is placed on early detection of
infestations and prevention of new infestations. The Alaska EPMT
generally takes an integrated approach, using a combination of the
following three methods to contain weed infestations and eradicate
them where possible.
Hand-pulling and root removal works for small infestations of most
species, but it's difficult, time-intensive, expensive, and requires
Cutting is effective for some species, like Melilotus
alba (white sweetclover),
but not others, like Cirsium arvense (Canada thistle).
Herbicides are generally most effective in controlling weeds and
stopping their spread, but they can be expensive and may have
environmental impacts if used improperly.
Before beginning any weed control effort, it is important to
consider what plant species are likely to colonize an area after
management and whether it is necessary to revegetate
the area with native plants or if it is possible to allow the area to
be restored through natural processes. Generally, the plant species
most likely to successfully establish and resist weeds at a disturbed
site are those native species commonly found in disturbed areas.
Native species that have been successfully used for revegetation in Alaskan parklands projects
include Hedysarum alpinum (eskimo
potato), Oxytropis campestris (milk vetch), Elymus
macrourus (tufted wheatgrass), and Poa alpina
(arctic bluegrass). Due to concerns about introducing non-local
genetics into the parks, all seeds and plants used are locally