PARTNERS AGAINST
WEEDS
Introduction
Invasive exotic plants are degrading wildland
ecosystems at a rapid and ever-increasing rate. Without major increased exotic plant
management efforts, these aggressive plants will continue marching through and degrading
lands we value so highly. Only if we act quickly, both locally and regionally, will
cooperative exotic and invasive plant management be economical and effective.
The Bureau of Land Management defines Noxious
Weeds as: "A plant that interferes with management objectives for a given area of
land at a given point in time".
The State of Nevada defines Noxious Weeds as:
"Any species of plant which is, or liable to be, detrimental or destructive and
difficult to control or eradicate..." (NRS 555.005)
Ecosystem health is a primary goal of the
BLM. One of the greatest obstacles to meeting this goal is the rapid expansion of invasive
and noxious weeds. These weeds can dominate many sites and often cause permanent damage to
native plant communities. Noxious weeds are increasing on western BLM-administered lands
at approximately 2,300 acres per day, but it is also important to remember that 95 percent
of BLM-administered lands are not yet significantly infested. Therefore, it is imperative
that we apply effective and economical strategies that are available to immediately
protect those lands from weed infestation. If local and regional cooperative weed
management efforts are not dramatically increased, approximately 19 million acres of
BLM-administered land will be infested with these invasive plants by the year 2000.
BLM recognizes that fighting weeds must be a
cooperative effort and that one agency cannot engage in the fight alone. We know that any
ongoing efforts with our partners must be continued and new cooperative efforts and
partnerships established where needed. BLM Nevada is committed to establishing
partnerships with State agencies, County governments, local branches of the Agricultural
Extension Service, Native American tribes and public interest groups to continue the
effort to prevent and control new and existing noxious weed infestations in the State. The
effort will require cooperation from all concerned, because the noxious weeds affect
everybodys use and enjoyment of the land, public as well as private.
How Serious is the Problem for Nevada?
Many people are not yet aware there is a
problem with noxious weeds in Nevada. Some people and agencies are just beginning to
realize the seriousness of the problem. A common perception is that Nevada is too dry for
weeds. Compare for example, the problems in Montana and Idaho which receive more rainfall;
expansive lands are infested with noxious or injurious weeds. To illustrate how
susceptible Nevada is to noxious weed infestation, the following examples are offered:
Weeds spread at a rate of about 14% per year
which equates to a doubling of the affected acreage in five years.
Yellow starthistle spread from one to
10 million acres within the 10-12 inch precipitation zone in northern California from 1980
to 1995.
Rush skeletonweed spread from 40 acres
to 4 million acres in a 10-12 inch precipitation zone in Idaho from 1964 to 1995.
Squarrose knapweed spread from a few
plants in 1954 to 140,000 acres in 1996 within a 8-10 inch precipitation zone in Utah.
Portions of this large infestation are now at the Utah-Nevada border and are suspected to
be present in Nevada.
Spotted knapweed was first identified
in Montana in the 1920s. It now covers 5 million acres in this state.
Medusahead has seen explosive spread
on public lands within the last ten years. Approximately one million acres of infestation
in Idaho and 2 million acres in Eastern Oregon.
What do all these examples have in common?
They are all within states surrounding Nevada. While the extent of infestations in Nevada
may be relatively small by comparison, Nevada is not immune. In fact, these infestations
are at or crossing the borders on every side of the State. We estimate that between 20 and
26 million acres of the total 70 million acres in Nevada are susceptible to weed
establishment and spread, based on occurrence of 8-12 inch precipitation zones.
Nevada is not too dry for weeds.
Noxious weeds are here and spreading. Recently, the Lamoille Weed District in northeastern
Nevada was formed to combat leafy spurge. The Lamoille Weed District is but one of
several new or forming weed districts in Nevada.
Where do noxious weeds come from and why
do they spread?
Exotic plants originally arrived from other
countries, without the natural enemies that kept them in check in their country of origin.
Consequently, these new plants are typically very aggressive and have the ability to
dominate many sites with dramatic impacts to native plant communities. Wildlife habitat
deteriorates, erosion increases, water quality diminishes, recreation values are degraded,
and exotic plants contribute to desertification.
What are some of the factors resulting in
the spread of weeds?
Weeds may be spread through a variety of
means including but not limited to vehicles, humans, horses, livestock, wind, water, and a
wide variety of wildlife. Leafy spurge may be spread by birds eating the seeds.
Increased population growth has resulted in soil disturbance for new roads, highways,
businesses and housing projects, providing avenues for weeds to spread. Weeds often follow
highway rights-of-way. For example, squarrose knapweed is following Highway 50 from
Utah and knapweeds have been identified on Sacramento and Conners Passes in eastern
Nevada. Increased Off Highway Vehicle (OHV) travel through infested areas to new areas may
spread weeds by seeds being caught in the undercarriage of vehicles or in tire treads. Use
of weed infested hay for forage may spread weeds. We now know weeds commonly invade
relatively undisturbed areas as well as sites that are disturbed.
These are just a few examples of how weeds
can be inadvertently spread. It is important to understand, no one intentionally
spreads weeds. Weeds are opportunistic and will spread themselves without anyone being
aware they may be providing the "vehicle" for that spread. Noxious weeds are a
problem which concerns us all, from the land manager to the farmer and rancher to the
recreationist and hunter.
What are the costs of noxious weeds?
The annual economic loss to the livestock
industry from leafy spurge alone in Montana, Wyoming, and the Dakotas. is $129
million. Weeds reduce forage for livestock, cost the industry millions of dollars; and, in
some cases render public lands and family ranches useless for grazing. Often times, weed
infestations will significantly lower land values in surrounding areas.
Closer to home, an aquatic weed, Eurasian
watermilfoil, is already infesting and spreading in Lake Tahoe threatening the natural
ecosystem by displacing native species and also threatening recreation uses by clogging
boat engines, boat docks and swimming areas, costing property owners over $150,000 to
control each year. The watermilfoil snarls on boat trailers and is inadvertently spread
around the lake and into other waters. What would be the cost, should this weed make its
way down the Truckee River into Nevada?
What can you do to help with weed
prevention?
There are many things public land users and
private landowners can do to prevent and control the spread of weeds in Nevada. The first
line of defense is awareness there is a problem and that the problem has solutions.
Secondly, we need to know where the weeds are and the extent of infestations. Once the
weeds are located, methods of treatment can be developed to address the problem. It may be
as simple as hand-grubbing a pocket of weeds out of existence or as complex as using a
variety of mechanical, chemical or biological controls. This is called Integrated Weed
Management - the use of several methods together to achieve control and eradication.
Often, one method alone will not be effective, but will require a variety of treatments
over time.
The following are some steps which can be
taken to assist in weed control.
When in the mountains, drive only on
established roads and trails away from weed infested areas.
When using pack animals, carry only feed
that is certified weed-free. Make sure the certification is for "all states".
What is considered a noxious weed in one state may not necessarily be a noxious weed in
the state where the feed originates.
Within 96 hours before entering back
country areas, feed pack animals food that is certified weed-free.
Remove weed seeds from pack animals by
brushing them thoroughly and cleaning hooves.
If you find a few weeds without flowers or
seeds, pull them and leave them where found. If flowers or seeds are present, place the
weeds in a plastic bag or similar container and dispose of properly.
If you find a weed infested area, let the
landowner or land managing agency know so they may take steps to control the weeds.
What you should not do:
Don't pick the flowers of noxious weeds and
take them home.
Don't pick and transport wild flowers that
you can't identify.
Don't camp or drive in weed-infested areas.
How do you recognize weeds?
Not everyone is a trained botanist, schooled
in the recognition of noxious weeds. However, there are ways to learn how to recognize
weeds. One way is to contact your local BLM field office and arrange a visit with their
Weed Management Coordinator. Some field offices have herbariums of specimens which can be
used for educational activities with schools, local 4-H groups, Boy Scouts, and other
groups. The field offices also have a noxious weed slide show with pictures of the weeds
as well as informational videos. Many State Departments of Agriculture have weed
identification handbooks with color pictures, such as the Wyoming Weed and Pest Council
Weed Handbook Series 1-30, which the BLM uses.
An excellent handbook on weed identification
is available locally through the University of Nevada Cooperative Extension. It is called Invasive
Plants in Nevada: An Identification Handbook SP 96-03. This useful handbook is
designed for the layperson and contains color pictures of the 22 most common weeds in
Nevada. There is also a survey reporting form in the handbook which may be used to inform
the Extension Service of the location of weeds you may happen upon. For more information
contact: Dr. Wayne S. Johnson, Department of Applied Economics and Statistics/204,
University of Nevada, Reno, Reno, NV 89557-0105.
Can a single individual really make a
difference in weed prevention?
The answer is YES. The following examples
demonstrate the value of awareness and the ability to identify weeds and taking quick
action.
In 1983, Elizabeth Neese, a BLM botanist in
the Vernal, Utah, BLM District, found the first known infestation of Dyer's woad on
Diamond Mountain. She eradicated it by hand and Dyer's woad has not been seen in
that district since.
In 1986, Forest Service employees on the
Ashley National Forest in Utah, noticed a new patch of leafy spurge about 75' x
100' in size. This small infestation, believed to have been introduced by woodcutters, was
treated with herbicide (Tordon) over a 6-year period. Annual monitoring shows this weed
patch was eradicated. Currently, there is no other known leafy spurge on the Ashley
National Forest.
In 1981, Cloyd Hess, Davis County, Utah
weed supervisor, noticed a new plant and sent it to the university for identification. The
plant was St. Johnswort which was immediately eradicated. Up until 1994 that was
the only St. Johnswort in Utah.
In San Pete County, Utah, in the 1930s, a patch of leafy spurge was found and
immediately eradicated. While nearby counties have infestations of leafy spurge,
constant vigilance has kept San Pete County free of leafy spurge.
In 1990, Oregon State Department of
Agriculture employees noticed a Dyer's woad plant in northern Malhuer County. It
was eradicated and currently there are no other known Dyer's woad plants in that
part of Oregon.
In 1992, yellow starthistle was
noticed in the Pueblo Mountains in the Burns, Oregon BLM District. Over 700 plants were
immediately pulled. Subsequent handpulling accounted for: 2,000 plants in 1993, 6 plants
in 1994, 30 plants in 1995, and only 3 plants in 1996.
In 1993, the Forest Service found small
scattered patches of yellow starthistle at Zig Zag Bench in Hell's Canyon.
Immediate handpulling was followed by handpulling during a video filming in 1994 and again
during a field trip in 1995. Only one plant was found on that site in 1996.
In 1992, five yellow starthistle
plants were noticed in a Selway-Bitterroot Wilderness outfitters camp on Boulder Creek.
Sarah Walker, Forest Service employee, pulled the plants, then monitored the site twice
per year. The population was eradicated.
These are but a few of the success stories in
the constant battle against invasive exotic plants. Were it not for these efforts, weed
infestations undoubtably would have "taken root" in these areas and the cost of
eradication would have been many times higher, if at all possible. Many species, such as leafy
spurge, once established, can only be checked in size and prevented from spreading
further; total eradication is nearly impossible. A person can make a difference!
Are there other ways a person or community
can make a difference?
There are many ways people can help.
Community service groups, schools, scout groups, 4-H councils, and others, can contact
their local land managing or agricultural extension office and work with them to
"adopt a patch". One University class undertakes field trips to a problem patch
and handpulls the weeds every year. Some people are trying to work with their local County
or State Departments of Transportation to establish "Adopt-a-Highway" sections
for weed control. When weed infestations are identified, it is important to work with your
neighbors to control them.
For more information on noxious weed
management and how you can make a difference, contact your local BLM field office, U.S.
Forest Service office, State Department of Agriculture, Extension Service, or Natural
Resources and Conservation Service.
For further information or questions
concerning Partners Against Weeds, please contact BLM Nevada Weed Coordinator,
Duane Wilson, Range Specialist, at (7775) 861-6587 or e-mail: d50wilso@nv.blm.gov
Click here for more information on
noxious weeds and
environmental education.
Remember, you can make a difference. Spread
the word, not the weed.
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