Our Most Invasive Plants
Of the nearly 200 non-native plant species in Sequoia and Kings Canyon
National Parks, fewer than half appear to have significant
impacts on park ecosystems. Many of these invasive plants (the foothill
annual grasses in particular) are so well entrenched and widespread
that it is not feasible to control them. However, many others are
recent arrivals and will be relatively easy to remove in the near
future.
In 2001, the Biological Resources Division of the U.S. Geological Survey published
an extensive
report detailing the characteristics of each non-native plant
species known to exist in Sequoia and Kings Canyon National Parks.
Each plant species was researched extensively and ranked according
to its invasive ability, its current distribution in the parks, its
ability to be controlled, and additional invasion characteristics.
The findings of this report figure prominently in Sequoia and Kings
Canyon National Parks' weed management program.
The plant species discussed in these pages are some of the most troublesome
in Sequoia and Kings Canyon National Parks. Most of them are
not well entrenched and can be removed if control efforts begin
soon. Most of these species are the targets of current or future control efforts.
Prevention is by far the most effective means of controlling
non-native plants. This fact is highlighted by the absence of yellow
star thistle in these parks. While several individuals have been
discovered, all were eradicated immediately and currently there are
no known populations in the parks. Each year, millions of dollars
are spent controlling this highly aggressive species in California.
It is abundant in many areas adjacent to Sequoia and Kings Canyon
National Parks. Early detection, costing almost nothing, has allowed
the parks to avoid a major eradication effort.
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