| Grassland Evaluation Contest Study Guide | Sixth Edition: December 2009 | ||||||||||||||||||||||||||||||||||||||||||||||||
| Practical Exercise and Scenario -Wildlife Habitat Score Card | |||||||||||||||||||||||||||||||||||||||||||||||||
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Objective: Evaluate grassland for its value to cottontail rabbits and bobwhite quail. A grassland manager who is interested in livestock production and wildlife must be able to recognize the requirements of both. It is important to remember that wild animals are not confined by fences. Although necessary feeding, nesting, or roosting cover may be provided within the grassland unit, suitable escape cover like downed woody structure and shrubby thickets may be located adjacent. The following scorecard lists factors to be considered when evaluating a specific tract of grassland, pasture, or hay field. The objective of this exercise is to improve habitat for rabbits and quail by identifying and addressing specific limiting factors. The grassland unit should be evaluated based on current conditions within the perimeter fence; however, certain questions require the examination of surrounding areas. An aerial photograph of the unit would be helpful with identifying habitat components in adjacent fields. A brief explanation follows each appraisal category.
Appraisal of Existing Conditions
It is important to know what general species of plants are present and what impact they have on the overall structure and diversity of the grassland. Fescue: Tall fescue is a common, extremely thick, sod-forming, introduced cool-season grass with little or no wildlife value. A grazing unit that is >90% fescue would have tremendously high stem density at ground level that would prohibit animal movement and suppress desirable wildlife plants. In fact, when fescue approaches only 40% of the pasture composition, it will be avoided by most wildlife species. Similar to fescue dominated pastures, introduced warm-season grasses crowd out important food plants, quickly invade bare ground, and restrict wildlife movement. In contrast to native warm-season grass dominated pastures, introduced warm-season grasses form dense sods that eliminate space between plants. Caucasian bluestem and bermudagrass are introduced warm-season grasses that have little or no wildlife value. Mixed cool-season grasses and forbs (< 25% forbs) : Mixed cool-season grasslands will contain a variety of species which may include fescue, orchardgrass, timothy, smooth bromegrass, redtop, Kentucky bluegrass, etc. This pasture composition is common throughout Missouri, but lacks a significant forb component to satisfy many wildlife species . Mixed cool-season grasses and forbs (>25% forbs): Any combination of common cool-season grasses, along with an adequate amount of forbs could constitute this pasture composition. This is the most desired cool season forage composition in Missouri. CSG-legume /forbs mixtures attract insects that comprise nearly all of the diet of young quail chicks. However, young birds and rabbits can only use pasture with this composition if properly managed for bare ground and low stem density, which allows ease of movement and growing space for other beneficial forbs. Legume dominant (>75%): Legume dominated pastures can be excellent for turkey poults, quail chicks, and many songbirds if they can easily move through vegetation. However, some legumes are more aggressive than others and may grow thick and tangled under favorable conditions. This impenetrable cover can inhibit movement by small wildlife in search of insects and succulent vegetation. The key is to manage legume dominated fields for adequate open space and bare ground. Alfalfa, annual lespedezas, native legumes, and white and alsike clovers are preferred. Deer, rabbits, groundhogs, and other smaller rodents are typically attracted to legume pastures as a source of food and cover. Native warm-season grass dominant (>50%): Properly managed native warm-season dominant grasslands can provide a variety of excellent cover types for many wildlife species. These grasslands should be managed for bare ground, desirable structure, and stand diversity in combination with other adjacent habitat components. An open mixture of warm-season grasses along with sedges, native perennial forbs including legumes, and seed-producing annual plants provide the diversity required by ground-nesting wildlife and many songbirds. A variety of insects are attracted to the forbs where they are fed upon by young birds and other wildlife. In addition, high quality native warm-season dominant grasslands provide a cool, moist summer environment and warm, dry winter protection.
Broadleaf plants, including legumes, improve grasslands for both wildlife and livestock. Lush, vegetative parts of most legumes and some forbs are sought and eaten by wildlife as well as livestock. Insect-attracting characteristics and robust seed production of these plants also benefit numerous bird and animal species that rely on them for food. With adequate structure and bare ground, grazing units with 5-50% of the canopy coverage in broadleaf, herbaceous plants normally provide ideal rabbit and quail feeding or brooding habitat. Grazing units expressing less than 5% canopy coverage of forbs usually confirm poor diversity and food availability. Exceeding 50% yields little additional benefit at the expense of grasses or bare ground and depending on species present, may inhibit livestock grazing. In fact, exceptionally high coverage or a monoculture certain legumes may also reveal low diversity of the grassland due to severe grazing, competition with other beneficial forbs, or overly dense growth with impenetrable conditions. Desirable legumes and forbs include alfalfa, clovers, tick trefoil, desmodium species, annual lespedezas, partridge pea, lead plant, bush clovers, indigos, sunflower, croton, and many others.
Consider all herbaceous and woody vegetation that is from 6-18” tall (about ankle to knee high). This vegetation is different from that in question two because regardless of plant species, any type of overhead canopy can provide protection from aerial predators. High quality, desirable cover will be sparse enough at ground level for easy movement though the vegetation by young quail and rabbits. The optimal range for 6-18” canopy coverage is 26-75%; beyond that range is less attractive. If canopy coverage at 6-18” exceeds 76%, vegetation will likely be too thick and inhibit movement of quail, rabbits, and turkeys. Likewise, fields with canopy coverage below 25% do not provide sufficient overhead cover and may increase predation, or may be avoided by species of wildlife that lack a sense of security.
Grazing height affects cool and warm season grasslands differently. Cool-season grasses primarily store energy reserves for rebuilding tissues in underground root systems. Warmseason grasses store a significant portion of their reserves in the lower stem in addition to the roots and have significantly greater root mass. These physiological differences allow cool-season grasses to be grazed to shorter heights without weakening plants. Therefore, the species composition of grassland must be considered when evaluating the height of vegetation and subsequent grazing pressure. Regardless of species, the height of vegetation during and after grazing a paddock is crucial for grassland wildlife. Ahead of grazing when forage grows undisturbed, quail may utilize the field for nesting but may soon be forced to abandon nests or move broods if plant height is uniformly grazed below 8”. Moving broods or attempting to re-nest later in the season, possibly in less desirable cover, will increase predation and diminish nesting success. Quail nests can also be destroyed by livestock trampling when stocking rates are too high. Heavily or severely grazed pastures oftentimes look like a short carpet of green grass. Grasses will be weakened in continuously, severely grazed pasture and will eventually allow weeds, woody vegetation, or nuisance species to increase. Any benefits of heavily grazed pastures to wildlife will depend on remaining species composition and structure. If a cool-season or native warm-season grass pasture has a history of heavy grazing, all grazing should be deferred for a growing season to improve the vigor and species composition of the stand. After a period of rest, the stand can be grazed but should be monitored closely to avoid removal of too much forage. Moderate grazing is defined as leaving 3-8” on cool-season or 8-12” on native warmseason pastures through the winter, on at least 75% of the grazing unit. Moderate grazing usually creates the most desirable wildlife habitat conditions. Under-grazing frequently results in overly tall forage throughout the unit during most of the year. For some species of wildlife, this can be just as detrimental as heavy grazing pressure. Very dense grassy vegetation, especially cool-season grasses like fescue, can restrict the movement of young quail from the nest. As with heavily grazed areas, wildlife benefits of lightly grazed grassland units are determined by the current species composition, structure, and density of the stand.
Idle areas that are relatively close to the center of the field are important to rabbits and quail. If managed properly they can provide excellent nesting and roosting sites, and often support seed-producing plants that quail need. Because the peak quail hatching period (around June 15) coincides with optimal grazing, these protected areas provide nesting sites which would otherwise be disturbed by livestock. When appraising grassland for wildlife, consider whether there are unproductive areas that could be protected and managed. When managing for rabbits or quail, it is best if protected nesting sites are present within 250 feet from the center of the field being assessed. Oftentimes, idle areas will require some type of management to be useful to wildlife (prescribed burning, light disking). Without periodic disturbance of the soil and/or vegetation, they will proceed through higher stages of plant succession and become less beneficial to many wildlife species.
Woody escape cover is very important to the survival of rabbits and quail. These areas include dense brushy cover, downed woody structure, fallen treetops or large limbs, etc. Suitable woody cover would be dense enough that a man would have great difficulty walking through it, and a coyote or fox would not be able to catch a rabbit taking refuge in it. An adequate patch of woody or escape cover is at least 1500ft2.
Large, open fields are less valuable to grassland edge species (quail and rabbits) than small fields. As described previously, quail prefer the field edges where more than one cover type is available in close proximity. Research shows that quail rarely move further than one-eighth mile (660’) between necessary habitat components. Cottontail rabbits require a variety of cover types that are even closer together (<250’). Hence, the interior of large, contiguous grassland would be utilized very little, if any, by these wildlife species. Quality concealment cover must be open at ground level, without sod, and allow easy movement by small animals and birds. Ungrazed woodlands, dense shrubs, downed brush, or other escape cover which affords security from predators or protection from the elements is appropriate. The portion of a pasture or hay field within 250’ of adequate woody cover generally represents the area that will be utilized by the quail and rabbits during average seasonal conditions.
Rabbits and quail thrive when a variety of cover types and feeding areas are close together. Rabbits prefer to move less than 250’ for essential habitat components, while quail will move up to 660’ if necessary. Crop fields that are more than 500 feet from the center of the grassland unit are beyond optimal range, and of limited value to rabbits and quail. A crop field or significant food plot (>1 acre) with no fall tillage, located within 250 feet from the center of the pasture is most advantageous for wildlife. Crop fields are an important part of bobwhite quail habitat, and offer other wildlife benefits. During the growing season, annual grain crops present desirable overhead cover, cooler temperatures, bare ground for ease of movement and dusting, and attract insects for growing chicks. Weedy areas which are skipped or survive herbicide applications contain high seed-producing annual plants that provide important quail food. Especially common in no-till cropping systems, crop residue and waste grain left on the soil surface after harvest can be an important winter food source for a range of wildlife. Standing crop stubble offers at least some security for quail, rabbits, and other small game that feed in these areas. Fields with crop residues that have been tilled under in the fall provide substantially less, or perhaps no benefit to wildlife until a new crop is planted and growing in the spring. In the absence of crop fields, annual grain food plots of at least an acre can be substituted where needed. Research also shows that a high number of bobwhite quail nests are located between 50’- 150’ from a change in cover type. Cover types with ample bare ground (crop fields, fallow ground, and disked areas) which are located next to properly managed grassland significantly increase the chance for quail to successfully hatch and raise a brood. Food plots, fire breaks, herbicide treatment, or burned areas within or adjacent to the field could serve the same purpose. Under grazing conditions, these practices could be implemented and protected in field borders without excessive impact to the livestock production system.
Wildlife Habitat Score Card Revised: December 2009
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