Factors That Effect the Value of Grasslands for Wildlife:
Different species of wildlife are attracted to grasslands for specific purposes. As an example, some birds may
seek nesting sites while others may use them primarily for over-night roosting. The following four factors
usually determine wildlife utilization of grassland:
- GROWTH HABIT OF THE GRASSLAND: Each species of grass has its own growth characteristics. The structure, or growth form and
arrangement of grassland plants, is important to wildlife. Some grasses have low growing leaves and
grow in dense stands that produce a sod (bermuda grass and tall fescue). Sod-forming grasses have a
very high stem density at ground level and quickly populate bare ground. This fact makes them less
attractive to ground nesting birds, because mobility is impaired and young chicks are not able to move
through the thick grass. Although some cool-season grasses form sod, not all sod-forming grasses are
difficult for wildlife to move through if managed properly, e.g. smooth bromegrass and redtop.
Most warm-season grasses and a few cool-season grasses like timothy form clumps and are called
bunchgrasses. Generally, bunchgrasses provide attractive habitat because small animals are able to
move between grass clumps without restraint. Broadleaf plants and legumes are able to grow in the
open space and provide beneficial food and cover. Alternatively, some bunchgrasses like Caucasian
bluestem are too dense at ground level and restrict growth of important forbs, creating a monoculture of
poor wildlife cover.
Ground-nesting wildlife, e.g. quail, rabbits, and prairie chickens, need vertical cover for nesting.
Adequate cover can be provided by either cool or warm season grasses, though there are differences
between these which must be incorporated into management. Because nesting generally commences
early in the spring before warm-season grasses begin new growth, overhead cover at this time could
only be provided by new cool-season grass growth or the previous year’s warm-season grass residue.
For nesting that occurs later in the spring or early summer, new warm-season grass growth can provide tall enough vertical cover for nesting. Therefore, when properly managed both cool and warm season
grasses can provide a good nesting environment early in the nesting season, though warm-season
grass may be better in late summer.
Similar vertical cover is also important for brood cover, but must include ample bare ground and many
seed-producing, insect-attracting forbs. Brood cover must be predominantly erect and easy to move
through for very young wildlife, while providing overhead protection from avian predators. Quality brood
cover may also benefit young wildlife by reducing the impact of harsh rain showers and moderating
humidity and temperature extremes. Studies show that during mid-June, ground-level temperatures will
be 21° F cooler and the humidity will be 29% higher in a native warm-season grass field than a corn
field. During the peak quail hatch around June 15, cooler temperatures and higher humidity creates an
ideal environment for the production of young quail. In addition, the tall, stiff, upright stems, and
elevated leaves of most native warm-season grasses and forbs can effectively reduce wind speed and
the wind chill effect on warm-blooded animals during winter.
- COMPOSITION OF THE GRASSLAND: Various species of grass are the main component of grassland, but legumes and other broadleaf plants
increase productivity for both wildlife and livestock. As previously discussed, many animals depend on
important broadleaf plants that attract insects and produce seeds. Prairie forbs have unique and
diverse flowering mechanisms which attract butterflies and other pollinating insects to ensure the
production of seed and persistence of the prairie. Thus, two of the most important factors that
determine the value of grassland for wildlife are the growth form and arrangement of the grasses, and
the diversity found within.
- SIZE OF THE GRASSLAND OR PASTURE UNIT: Livestock are strong and mobile, moving to find available forage within any size fenced pasture.
Wildlife is not confined by fences, but is constrained by their ability as a species to safely travel for food
and cover. Rabbits and quail in particular require habitat components near one another for safe
movement (within 250’).
Many species of wildlife, including rabbits and bobwhite quail, concentrate fundamental activities near
the "edge" of grassland fields. Edge is defined as a location where two different cover types meet.
These transitional zones contain a mixture of plant species and structure found in each of the distinct
cover types, which is attractive to wildlife. For many small animals and birds, an edge provides multiple
cover types used to satisfy life cycle requirements in close proximity. As a result of this increased
convenience, predation is less likely and survival rates increase.
For certain grassland wildlife, the transition area between grasslands and woodlands, old fields, or crop
fields is critical. Rabbits require grassland vegetation for food in addition to brushy escape cover to
survive pressure from predators. While quail could utilize the interior of large, open, properly managed
grasslands, they too are most often found near the edge. A well managed edge can provide colonies of
protective shrubby cover along with a rich variety of seed-producing, insect-attracting plants -
everything they need, with greater security.
For the livestock or hay producer, grassland management practices are usually directed toward
maximizing production of forage and destroying valuable wildlife cover. Periodic controlled burning of
grassland to increase production will eliminate live shrubs and downed brushy cover unless specifically
protected from fire. When managing for rabbits and quail, it is important to realize that they may fully
utilize a properly managed 20 acre grassland, but may never use the interior of larger, poorly managed
fields which lack adequate, well-distributed protective cover. Research suggests that in a grazing
situation, greater nest success will result from paddock sizes of 10-20 acres. Patch burn grazing creates usable large fields due to the mosaic of structure and cover created with the technique.
Remember however, that a large, open grassland with little or no woody cover is important when managing for
"open-land" prairie species like prairie chickens, upland sandpiper, and meadowlark. Well managed grasslands of at least
250 acres should be available for these open prairie species.
- MANAGEMENT OF THE GRASSLAND: When managing grassland for wildlife our primary goal is to set back plant succession. Management
practices which create bare ground will stimulate a diverse array of new plant growth from seeds in the
soil seed bank. By promoting these so-called "early successional species":, the grassland will flourish
with a variety of vegetation and habitat conditions that favor wildlife food and cover. Plant species and
structure diversity can be enhanced with prescribed fire, herbicide treatment, or mechanical disturbance
(i.e. disking, grazing, seeding, or mowing). Similar and beneficial results can be achieved using each of
these practices, depending on the timing and current stage of growth in the grassland. Likewise,
performing these practices at the wrong time can degrade grassland and reduce its value for wildlife.
In grassland used for agricultural production, timing and method of harvest are likely the most critical
factors affecting their value for wildlife. Grasslands are usually either hayed or grazed by livestock for a
designated period of time.
When grassland is cut for hay, the effect is immediate and unexpected by wildlife. Food and cover
vegetation is removed within a very short amount of time, forcing wildlife to move to adjacent areas or
be exposed to predators. The negative impact of haying on wildlife can be reduced by leaving a 30’
wide uncut perimeter around the field, in addition to strips across the center of larger fields. These
uncut areas provide usable, residual cover which can be harvested at a later date.
In contrast to haying, grazing normally removes food and cover vegetation over a longer period of time.
Based upon the management of the grazing system, livestock may graze from as little as one day to
continuously. The rate of vegetation removal will be determined by two primary factors: 1) Stocking
Rate and 2) Grazing Period.
Livestock grazing is generally managed using a continuous or rotational system. Continuous grazing allows livestock in one grazing unit to graze for a long period of time, selectively choosing the plants they eat. Oftentimes, continuous grazing results in the near elimination of certain choice plants (decreaser plants) and allows the introduction or spread of plants that are not as palatable to livestock (increaser plants or invader plants). Severe, continuous grazing reduces forage production and eliminates wildlife cover and food. Depending on the stock density in a continuous grazing system, cattle trampling can also destroy wildlife nests. Years of relentless, continuous grazing can transform productive grassland into undesirable, inadequate plants.
Conversely, light to moderate seasonal grazing can produce very good nesting and brood cover.
Grasslands which are lightly to moderately grazed will contain a mosaic of patches which range from
heavily to lightly grazed. This diversity of vegetative structure and plant species is attractive to wildlife.
However, even light and moderate grazing for extremely long periods of time can result in loss of
desirable forage plants which are continually re-grazed by livestock. Due to the "spotty" nature of
continuous light to moderate grazing, nearby patches of these same desirable plant species may be
passed over and allowed to mature, making them unpalatable and undesirable by the livestock for
future grazing. Two management techniques that can help solve this problem are rotation grazing and
prescribed burning.
Rotation grazing may be as simple as switching livestock between two grazing units or pastures, but
often works best with more than two grazing units. So-called "Management intensive Grazing" (MiG)
can result in higher production for the grazing herd through lower stock density and higher pounds per
day gain per head. Rotational systems require more management on the part of the operator due to the active movement of livestock through smaller grazing units (paddocks), on a schedule ranging from
twice daily to once per week. It is important to note that the proper term for this type of grazing system
is "Management intensive Grazing", because it is the management and not necessarily the grazing that
is intensified.
Grazing units are "rested" when they are left idle or allowed a break between grazing periods. Resting
a paddock increases the vigor of choice plants, affording them a chance to rebuild vital tissues,
replenish energy reserves, and perhaps reproduce. This gradually restores or increases the quality of
plants within the grazing unit. More plant diversity and vigor in the grazing system will result in
increased livestock production and appeal to wildlife. It is important to realize that optimal rest periods
are normally longer for native grasses (35-60 days) than for cool-season grasses and legumes.
The value of an individual grazing paddock to wildlife depends on 1) the amount of residual vegetation
left after grazing, 2) stock density, 3) the duration of rest (especially after grazing at high stock density),
and 4) the size of the paddock. Bobwhite quail will not use very short cover or small paddocks if stock
density is greater than one animal per acre, as is often with rotational grazing. Nest trampling will likely
occur at high stock densities and sufficient residue must remain for nest initiation.
Ideally, the paddock resting period must also allow enough time for nest building, egg lying, and
incubation before livestock return. At minimum this would require 35 days, nearly matching the
optimum rest period for native warm-season grasses (42 to 49 days). Most rotational grazing systems
will provide succulent forage for livestock, simultaneously allowing some areas to grow undisturbed.
Areas that are ungrazed and resting, or areas that are a mosaic of light to moderately grazed can
provide wildlife habitat if the vegetative structure and length of rest is adequate.
Prairie remnants and planted native warm-season grasses may be used for rotation grazing and also work well in a grazing system called patch-burn grazing. Patch-burn grazing involves the rotation of burned patches within perimeter-fenced grasslands to distribute grazing pressure from year to year. Each winter or spring one-third to one-fourth of the entire grazing area is burned, consequently focusing grazing pressure on the lush, new growth of the burned patch. Livestock tend to prefer tender, new growth and graze it much shorter and more often than unburned portions. Each year a new patch is burned and the previously burned patch will be grazed significantly less, allowing it to rest until burned again. Livestock have access to all parts of the pasture but only graze the burned portions very short, leaving taller residual vegetation in the lightly grazed, unburned portions. Patch-burn grazing provides excellent nesting and brood cover.
If fire cannot be used to create burned patches, producers can simulate patch-burn grazing with mowing or fencing. Focus heavy livestock grazing in designated areas and lighter grazing on the remainder by mowing patches or fencing in early spring. The disadvantage to these alternative methods is that litter is not effectively removed and buildup can contribute to high nest predation in addition to difficult brood movement. Mob grazing (ultra-high stock densities) can help control litter accumulation but must not occur on areas used for nesting because high stock density causes nest trampling.
- WILDLIFE COVER IN GRASSLAND:Pastures and hay fields that are isolated from other habitat components are of little value to rabbits and
quail. They readily use woody cover for protection, idle grassy areas with bare ground for nesting, and
crop residues or weedy patches for feeding and raising broods. These cover types must be intermixed
within the grassland or located nearby.
Quail and rabbits rely on a variety of cover types to meet seasonal life cycle requirements. In areas
where wildlife habitat is optimized, grassland only provides a portion of what is needed during the year.
Low growing shrubby cover and woodlands provide thermal protection in the summer and, if dense
enough, predator and weather protection in winter. Crop fields oftentimes provide summer brooding
habitat and high-energy waste grain after harvest in the fall and winter. Fallow weedy areas and food
plots are foraged for seeds throughout severe winter months and into spring where insects emerge or
new growth is available. When left idle they may also be used for nesting, along with protected odd or
idle grassy areas that are managed appropriately.
Grassland which differs significantly from the field being evaluated will also lend to the diversity of
habitat components that allow quail and rabbits to thrive. To be considered, the differences must be
easily apparent and offer alternate cover for nesting, feeding, brooding, roosting, loafing, predator
protection, etc. Beneficial variations between grassland may include growth habit, structure, species
composition, and management (cool vs. warm season grasses, monoculture vs. many species,
monotypic cover height vs. varied vertical structure, heavily grazed grass "carpet" vs. burned or disked
idle grassland, etc.). Additional cover types should be available that are protected from grazing.
Properly managed grasslands can provide a variety of cover for wildlife activities including nesting,
roosting, brooding, and winter protection. Herbaceous cover or soft cover is the vegetative growth
consisting of grasses and non-woody broad-leaved plants. The majority of short cover in grassland is
herbaceous. Herbaceous cover is used primarily for nesting, brooding, feeding, and sometimes
roosting or loafing. Shrubby cover or brush refers to low growing woody cover provided mainly by
shrubs. Shrubs are low-growing woody plants, usually with multiple stems that arise from a common
base. Most shrubs reach only 3-12’ at maturity and branch structure is close to the ground. When they
grow close together to form a thicket (high stem density), they provide excellent protective cover for
quail and other small animals. Quality shrubby cover is barren underneath, without sod or thick
grasses that could inhibit movement by small animals. Brushy areas produce mast and browse for
many animals, and the dense branches provide nesting for many songbirds.
Escape cover is a term used to describe an area where small birds and animals can escape predators
such as foxes, coyotes and hawks. It may consist of live or cut brush, dense shrubs, brambles, or other
well-branched woody structure with bare ground underneath. Quality escape cover provides a barrier
which is extremely difficult for a predator to move through and is protected from grazing. Grazing can
degrade escape cover and limit its usefulness to wildlife.
Patches of escape cover need to be large enough for animals to use and feel secure from predators.
Ideally, they would be distributed so that the entire grassland could be used by wildlife for nesting,
brooding, or feeding without excessive vulnerability.For quail and rabbits, a patch of escape cover should be at least 1500 ft2 (30'x50') and provided within or adjacent to each 10 acres of grassland. To
be considered adequate, escape cover must have high stem or branch density with intertwined
branches that yield nearly continuous cover. In grassland lacking suitable dense woody cover, artificial
escape cover can be created using cut brush. This downed woody structure is best arranged by
placing several large trees closely side by side so that their branch tips intertwine and form continuous
cover. Alternating the trunk direction of well-branched, sturdy tree species like shingle oak, pin oak, or
hedge works best and last longer than softer species. Select optimal locations for downed woody
structures and eliminate ground cover before placing material.
An idle area is a patch of cover which is protected from grazing and otherwise unused for agricultural
production. An idle area can be a combination of one or more cover types. These small areas can provide part of the life cycle requirements for grassland wildlife. To be useful, idled areas need to be at least 30' wide, ¼ acre (approximately 100'x100') and found within or immediately adjacent to the grassland field (i.e. fenced pond, odd corner, etc.). Suitable idle areas which are along a significant portion of the field perimeter can be considered part of a field border. A field border refers to a strip of
vegetation around the perimeter of a paddock or field that differs from the vegetation within. Field borders are generally some type of useable wildlife cover and should be at least 30' wide.They may
be created by protecting existing cover from haying or grazing, establishing new cover, or otherwise
shifting management in those areas. Wildlife can use the resulting changes in vegetation to fulfill life
cycle requirements when the field itself is unsuitable. Field borders are especially beneficial when
adjacent fields are grazed or hayed, leaving very little wildlife cover over large landscapes. To satisfy
minimal wildlife needs in fields less than 20 acres, 25-50% of the field perimeter should be bordered.
Larger fields need 75-100% of the perimeter in field borders to be attractive and valuable to wildlife.
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