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Native Prairie Management Guide
By Ray Hamilton,
Objectives For Prairie Management:
The purpose of prairie management is to
preserve and enhance the natural qualities of the prairie and its biodiversity.
The management of prairies includes the
simulation of the natural mechanisms that have allowed the prairie to survive to
out time such as grazing, fire, and at times lack of these influences. Other
factors include weather and geological and zoological agents. Management also
includes active human intervention such as domestic grazing, mowing, and haying
as well as manual, biological, and chemical means of selectively removing
undesirable species. Passive techniques include monitoring sites that do not
require intervention, fencing, and providing buffer areas.
Influences such as grazing, fire, soil
disruption, weather change or nonintervention will cause certain species to
respond either beneficially or negatively. Management techniques should be
chosen for their beneficial effects. Such management techniques should be
carefully applied to small portions of each biological community, so as to leave
a refuge for species which may be harmed by the given management technique.
Historical Features Related To Prairie
In general, prairies thrive by occasional
influence of grazing and fire. Without such influences, the prairie grasslands
progress by succession to poor quality woodlands
Grazing is a natural phenomenon. Herbivores are
an important component of the prairie ecosystem. Their natural actions include:
grazing, uprooting and trampling vegetation, wallowing in mud holes, and
creating hoof depressions. They cause considerable damage to woody vegetation by
browsing, gnawing, and rubbing. Grazing, like fire probably was fairly random
and irregular, although sometimes locally intense and repetitive.
Fire patterns were probably patchy, random, and
irregular, depending on wind, temperature terrain of the land, and the amount of
fuel left by grazers. Some fires were started by Native Americans. These factors
would have left unburned swaths of land, which allowed the survival and
enhancement of species adversely affected by fire.
It is worth noting that many of our high quality
prairies survived modern settlement most often by one of two means. One way was
cutting the prairie for hay one or two times per year. The other way was light
intermittent grazing. Most had a component of neglect and a lack of active
management. Many had very infrequent fire exposure between settlement and modern
day active management.
Original fire and grazing patterns remain
undetermined. Soil surveys, historical accounts, tree ring studies, and land
surveyors' notes are used to help identify original biological components, and
fire and grazing patterns. These finding may not represent original pre-1700
conditions due to dramatic culture influences and reduction in grazers during
transitional times (1700's, 1800's). The reduction in grazers may have caused
flammable biomass buildup resulting in more frequent fires during traditional
Today, our prairies are fragmented and isolated
from each other. Such fragmentation prevents the natural free flow of seeds,
animals, and other genetic from one prairie to another.
General Management Guidelines
A biological survey should be taken of all
major plant and animal groups, and updated regularly. Contact the Iowa
Prairie Network, County Conservation Board, or State DNR natural areas staff
for individuals to help with surveys.
A Specific plan with goals should be
established for each prairie. Take into account management need, problems,
alien species, threatened and endangered species, availability of help
(manual labor, equipment), and adjacent land use. Make maps.
Treat only small portions of the prairie
(fire, mowing, grazing). Avoid single universal treatment of a prairie tract
so as to avoid extirpation of species and to minimize other negative effects
on susceptible species.
More specifically, divide the prairie into
biological communities. Allow only a fraction of each community to receive
disturbance (by fire, grazing, mowing) each year. The purpose of this action
is to leave a refuge for species which may not be harmed by the given
Diversify treatments. Treatment techniques as
well as time of application should be varied, from year to year, for each
gain control over unwanted woody vegetation
by manual removal so that subsequent re-growth can be more efficiently
controlled by use of a tractor mounted mower (and grazing and occasional
Record past and present influences and
management techniques. Record the effects of management . Evaluate and
revise the management plan regularly.
Some prairies have a low need for management
and should be left alone as a type of management.
Plant and animal specimen collection and seed
collection should be regulated so that it does not harm the prairie
community. Legitimate benefits of specimen collection include enhancement of
local native prairies, and research that will provide increased public
Do not introduce wildlife cover, food plots,
or alien trees.
Introduction of native species; Introduced
genetic material should be locally derived as well as site and soil
specific. The side of origin should be recorded. See "INTRODUCTION OF
Use small segmental burns. The prairie should
be broken down into biological communities. Each biological community should
be divided into five or six patches with representative biological
components in each patch. Burn one patch (subsection) per year, maximum. For
example, a prairie with a dry knoll and a mesic plateau should have only a
small portion of the knoll and a small portion of the plateau burned on a
given year. Utilize strips which traverse the small portions of each
How often should you burn? Consider every 10
years combined with mowing and grazing. Standard burn cycles are often 2 or
3 years; however, negative effects of fire and possibility of species
extirpation have resulted in suggestion of 10 to 30 year cycles. Leave some
sections burn free permanently. Black soil prairies with high biomass
production may require more frequent fires than dry, sandy, or rocky low
Burn in long linear shapes. This method
provides a longer border for slow-moving species with several year recovery
times to repopulate.
Avoid burning contiguous parcels in
consecutive years. This play allows species to repopulate. Use multiple
Avoid re-lighting areas that were skipped by
burns. These areas provide a natural refuge for species harmed by fire.
Minimize backfires since these may result in
a longer exposure to a hotter fire at the surface
Create fire breaks by moving the breaks the
summer before the burn. This practice allows for disintegration of debris
and hence cleaner breaks and less labor into raking away debris. Fire breaks
can be created by mowing, hand brush cutting, plowing adjoining non prairie
land, or by using roads, creeks, paths, etc.
vary the timing of burns. Invading alien cool
season species are commonly battled with a spring burn after the alien
species have leafed out and greened up. Consider varying the time of burns,
so as not to artificially select spring burn favored communities.
Consult other sources for specific burning
Large herbivore grazing should be considered for
occasional, brief periods of intense grazing (simulation natural grazing) on
small subsections as delineated under "FIRES". Livestock should be
quarantined for two days with weed free hay prior to their introduction onto the
prairie in order to remove seeds from their digestive system. Prairie grazing
increases efficiency of farming operations due to high nutrition and relieving
pressure on cool season pastures.
Native species (bison, elk) are recommended for
grazing. Availability and practical concerns presently limit this choice.
Prairie managers need to encourage the improved availability and use of native
herbivores. Site specific herbivores can be considered (bison for open mid and
tall grass, elk for savanna).
Domestic grazers such as sheep and cattle are
less desirable; however, they will work for short periods of grazing. Domestic
animals feed differently than native bison, elk, rabbits, prairie dogs, insects
and other herbivores. For example, bison preferentially feed on grasses whereas
domestic grazers selectively reduce some flowering species. Cattle grazing will
yield a different, less natural biological community than bison grazing.
Mowing / Haying
Mowing and haying simulate some features of
grazing and are helpful and efficient in treating large areas of woody
vegetation and alien weed overgrowth. Consider occasional mowing and haying
during the growing season on small subsections as delineated under
"FIRES". Prairie hay is desirable for livestock feeding.
We also need to consider the effects of soil
disturbance. Some species thrive with soil disturbance from burrowing or
1) General Issues: Cut or mow after plants
have been fully leafed out (energy stores above the ground) but before they
have trans-located significant winter stores to roots- perhaps mid June
through August. This cutting can be achieved by use of chain saw, brush
cutter, pruning shears or a mower on a tractor. Setback of woody species can
be maximized by cutting and re-cutting sprouts more than once per year as
well as re-cutting in successive years. Removal of lager trees should be
done in that winter with frozen ground and snow cover in order to protect
the suppressed under-story species.
The suppressed under-story vegetation may be
only sparsely visible initially; however, it will rebound nicely in
subsequent years with proper management.
Trees and medium diameter brush: Ring trees
with a chain saw or remove the cambium manually in the summer, and leave
standing. Remove trees in the winter.
Small brush and re-sprouts: Cut and re-cut in
summer. Remove from prairie if dense so as not to cover under-laying
vegetation, otherwise may leave in place. Consider herbicides for difficult
species such as sumac and black locust (see "HERBICIDES").
Cedars: Cut and remove in winter. No
herbicides needed. Cedars are easily killed by fire.
Brush piles: Create piles on disturbed ground
(i.e. previously tilled ground). To not place on grassy areas or on adjacent
brushy areas since such areas may spring back to prairie when cleared and
managed. If brush is piled there it will sterilize the existing native
vegetation, soil, and seed bank and the area will fill with weeds.
Vines (on trees to be removed): Consider
stump treatment with herbicides before the tree is removed so that they
don't spread horizontally on the ground after the tree is removed.
Bison/grazers naturally control woody
Leave some woody plants untouched since they
may provide a different local environment for unusual species.
Annuals and Biennials (bull thistle,
sweet-clover, etc.): Cut at the time of flowering in order to remove the
reseeding potential. Properly timed fire of cutting may be appropriate.
"Pulling weeds by roots" can be effective for isolated weeds;
however, keep in mind that disturbed ground left by this maneuver can invite
Perennial weeds: Routine prairie management
(mowing, burning) will conquer many weeds.
Perennial weeds with underground stolons
(Canada thistle, leafy spurge, etc.): Stump treatment with 33% Roundup is
efficient for small populations. Leafy spurge is a serious problem that can
completely overtake grasslands. It aggressively colonizes disturbed areas.
Roundup 1 to 2% spray is effective. Some prairie managers use Tordon 22K or
a 10% solution of Tordon RTU topically; however, note severe adverse effects
in "Herbicides". Yearly vigilance is required.
Cool season grasses and weeds: Use late
spring burns after the aliens have leafed out. Routine management and
succession to prairie will set back these species.
Biological Control Agents
Biological agents such as insects are being
investigated and utilized against specific problem plants. This method is being
studied for its effectiveness against Leafy Spurge and Purple Loosestrife.
Through studies need to be done in order to
identify adverse effects on native specific. The user has a responsibility to
review and understand these effects.
For assistance, contact the states office of The
United States Department of Agriculture (USDA), Agriculture Research Service, as
well as university agricultural research center.
General issues: Herbicides may be required
for aggressive species and species that create underground suckers from
mechanical treatments. These species include sumac, black locust, leafy
spurge, and Canadian thistle. This is especially true for areas without
available grazing or mowing capability or lack of labor to administer
repeated mechanical treatments.
Stump treatment is more specifically directed
and is considered the safest application technique. Hand wick application is
fairly safe; although the potential for drip exists. Spraying causes damage
to adjacent plants by drift and should be avoided or used with extreme
Caution: Chemicals can trans-locate to
adjacent plants through the soil and roots. Research regarding herbicide
effects on high quality prairies is sparse. Caution should always be taken
when using herbicides.
Specific: Name the herbicide, mode of
application, species and area to be treated, time of application, and names
of persons who will be applying the herbicide.
Read the directions with the chemical.
ROUNDUP- Roundup apparently is broken
down quickly and doesn't trans-locate to other species through the soil,
which makes it a preferred herbicide. Stump treatment with a 33% solution of
Roundup is efficient and should presumably protect surrounding preferred
plants. Adjacent plants will die if there is a direct root to root contact.
It should be applied sparingly to the perimeter cambium layer of the tree or
weed in late summer (four weeks before leaf color change) when
trans-location to the roots is actively taking place. Spray (!% to 2%)
directed stream spray (5% to 7%), and wick (33%) treatments should be done
when the plant is actively growing. Roundup will kill any plant upon topical
contact. Spray and wick treatments can cause elimination of surrounding
preferred plants by drift and drip. Visible effects of the plant's decline
may not be evident for many weeks or longer.
TORDON- This chemical trans-locates to
the surrounding plants through the roots and should not be used on high
quality prairies except in extreme conditions, in such cases that the loss
of surrounding vegetation is acceptable.
Other chemicals may be acceptable, and
controlled studies of effects on remaining vegetation is welcomed by prairie
Introduction of Native Species
Introduced genetic material should be locally
derived as well as side and soil specific. The site of origin should be
recorded. Nearby prairies can be used as models and seed sources. Reasons for
introducing a new species includes providing a local refuge for unusual species
which allowed it to adapt to that site (out-breeding depression). Reasons for
supplementing an already existing species includes restoring a declining
species, especially if there is a lack of seeds/genetic material from the
Adjacent Land Management
Inventory, create a plan, and follow
guidelines as discussed in "GENERAL MANAGEMENT GUIDELINES."
Enhance the native, natural qualities of the
Create a native buffer zone using locally
derived, soil and site specific species (i.e. dry sandy species for dry
Increase the diversity of habitat in
appropriate sites. This practice will allow survival of marginal species
that require mixed habitats.
Enhance habitats for locally rare or
Remove unnatural features.
Revive degraded areas that degraded condition
promotes unusual species. If the land has not been tilled or otherwise
significantly impacted, native vegetation will often return with management.
IF, after several years of management, native vegetation doesn't return,
then reconstruction of site specific prairie or savanna vegetation and
animals may be considered.
Prevent runoff or drift of soil, weeds,
pesticides, and air-born pollutants onto the prairie.
Do not plant alien, invasive species such as
crown-vetch, purple loosestrife, sweet clover, birdsfoot trefoil, pampas
Challenge: Dynamic Communities
Special management is needed for species that
thrive in a mobile community such as the woodland/savanna/prairie edge, or a
transient community such as that which would thrive in a trampled mammal path.
Mobile communities are moving from year to year
depending on the fire, grazing, weather, and other physical pressure that
controls their presence. For example, the purple milkweed may thrive on the
leading edge of the savanna along with the dogwood and sumac. Nearby, the showy
orchid is growing under the advancing May apples and oaks in a semi-closed
savanna. The management challenge in these cases is to create and maintain an
appropriately staged mobile woodland/prairie edge for such species. Community
motion can be created by allowing savanna vegetation to creep gradually onto the
prairie. Alternatively, this community junction can be maintained in steady
state by cutting woody vegetation and allowing savanna vegetation to creep
gradually onto the prairie. Alternatively, this community junction can be
maintained in steady state by cutting woody vegetation and allowing re-growth at
the same site.
Examples of transient environments include
compaction and disruption from deer paths, mammal wallows, mammal burrows, and
mammal foraging and rubbing. Such impacts may explain why Great Plaines ladies
tresses are sparse on one high quality minimally impacted prairie, while they
thrive in an adjacent (mechanically made) road ditch. We need to allow for
various influences in the management of prairies, so as to allow the survival of
species requiring such various influences. At the same time we need to avoid
excessive treatment to allow survival of species harmed by such treatment.
The author wishes to thank the many
prairie enthusiasts who have helped contribute to this guide.
Revised 5 April, 1997