State 1
Grassland State

The Grassland State defines the ecological potential and natural range of variability resulting from the natural disturbance regime of the Clay Lowland ecological site. This state is supported by empirical data, historical data, local expertise, and photographs. It is defined by a suite of native plant communities that are a result of periodic fire, drought, and grazing by bison. These events are part of the natural disturbance regime and climatic process. The soil dynamic properties that can influence community phase and state changes are organic matter content, biological activity, aggregate stability, infiltration, soil fertility, and soil reaction. Other grazing and feeding animals such as elk, pronghorns, deer, rabbits, insects, and numerous burrowing rodents had secondary influences on plant community development. Today, cattle are the primary grazers on this ecological site. Within the grassland state, the woody vegetation will generally be less than 15 percent canopy cover per acre. If introduced, invasive or noxious plants are present, they should not exceed 15 percent of the total pounds of vegetation produced per acre in order to avoid crossing a threshold. Plant communities within this state function similarly in their capacity to limit soil loss, cycle water, and produce vegetative biomass. The plant community phases can vary through changes in grazing management or fluctuating climatic conditions. The variables that control the resilience of this grassland state are long-term grazing management and frequency of fire.

Characteristics and indicators. Tallgrasses and Migrasses are dominant in the Grassland State.

Resilience management. Management strategies that will sustain this state include monitoring key forage species and providing a forage and animal balance.

Community 1.1
Reference Plant Community

Figure 11. MLRA 76 Reference Plant Community.

The interpretive plant community for the Clay Lowland ecological site is the Reference Plant Community which represents the original plant community that existed prior to European settlement. The site is characterized as grassland with only occasional trees and large shrubs. It is dominated by tall-, warm-season grasses, and forbs. All of these grasses and most of the dominant forbs are strongly rhizomatous. These underground stems often form a dense, intertwined mass throughout the upper four or five inches of the soil profile. Tallgrasses include big bluestem, Indiangrass, switchgrass, eastern gamagrass, and prairie cordgrass. Combined, these tallgrasses will account for more than 70 percent of the total vegetation produced annually. Little bluestem and sideoats grama are the major midgrasses. Other prevalent midgrasses and grasslike plants are Canada wildrye, Virginia wildrye, western wheatgrass, marsh bristlegrass, composite dropseed, and several species of sedges and rushes. A number of very palatable forbs are found interspersed throughout the grass sward and include Maximilian sunflower, sawtooth sunflower, pitcher sage, compassplant, wholeleaf rosinweed, and prairie bundleflower. Other important forbs are American licorice, Nuttall’s sensitive-briar, slimflower scurfpea, common milkweed, and prairie fleabane. Water loving plants (hydrophytes) associated with this site include those of emergent wetland inclusions (hydric soils) that often occur within Clay Lowlands. Some of the more common species found might include broadfruit bur-reed, broadleaf cattail, river bulrush, field horsetail (scouringrush), arumleaf arrowhead, swamp milkweed, Pennsylvania smartweed, swamp smartweed, curly dock, devil’s beggartick, annual marshelder, rough barnyardgrass, and yellow nutsedge. Desert false indigo and common buttonbush are shrubs that commonly occur in moist soil situations, often immediately adjacent to a stream or wetland area. Eastern cottonwood and black willow are the major trees in the broad bottomlands and are generally located along streambanks. Although the major portion of the site is dominated by herbaceous plants, isolated areas do support groves of trees. Protected by streams and rivers, some areas historically escaped the intensity of wildfires and often developed a savannah plant community with an overstory of hardwood trees that may include eastern cottonwood, black willow, bur oak, American elm, green ash, and black walnut. Eastern cottonwood is usually the dominant tree and often forms large, single-species groves. The understory in these situations usually supports shade tolerant, cool season plants such as Canada wildrye, Virginia wildrye, Kentucky bluegrass, and sedges. This is a stable, resilient and very productive plant community when adequately managed. A prescribed grazing program that incorporates periods of rest and recovery during the growing season perpetuates the more palatable species of tallgrasses and forbs. In a number of locations this plant community is managed exclusively for hay production. Mowing tends to reduce the amount of switchgrass and prairie cordgrass and favor big bluestem, Indiangrass, and eastern gamagrass.

Resilience management. This is a stable plant community when grazing and fire are adquately managed. A prescribed grazing program that incorporates periods of grazing rest and recovery of key forage species during the growing season benefits the tallgrasses and even the more palatable forb species. Early management programs involving transient steers shipped into the area were effective in maintaining a plant composition closely resembling the reference plant community. Pastures were burned in the spring and grazed from green-up until mid to late July when steers were transported to market. The vegetation was then rested the remainder of the growing season permitting full recovery of most plants.

Community 1.2
Tallgrass/Midgrass Plant Community

The composition of this plant community is dominated by a mixture of tall and midgrasses. Compared to the Reference Plant Community, there has been a decrease in the more palatable tallgrasses and forbs and a subsequent increase in midgrasses. Although reduced by overgrazing, tallgrasses such as big bluestem, Indiangrass, and switchgrass remain dominant. Prairie cordgrass may even increase, especially on the wetter sites. The midgrasses, sedges, and rushes increase. These include composite dropseed, little bluestem, western wheatgrass, marsh bristlegrass, and sideoats grama. Secondary grasses include Kentucky bluegrass and vine mesquite. Combined these secondary plants now comprise 30 to 40 percent of the total herbage produced annually. Common forbs are white heath aster, white sagebrush, Cuman ragweed, interior ironweed, and Canada goldenrod. Forbs produce 8 to 10 percent of the total herbage. In some locations the site supports increasing amounts of shrubs and trees. The most abundant shrubs are desert false indigo, common buttonbush, roughleaf dogwood, smooth sumac, and coralberry. Eastern cottonwood, black willow, and American elm are the major trees found on the site. Shrubs and trees usually comprise 5 to 10 percent of total production.

Resilience management. Periods of rest and recovery from grazing are essential in maintaining the production of some of the major grasses found in this plant community. Eastern gamagrass and big bluestem are especially preferred and selectively grazed by cattle. When the site is grazed continuously throughout the growing season, these grasses are usually overgrazed and thus maintained in a lower state of plant vigor. When continued for many years, overgrazing results in a gradual reduction in the abundance of these grasses. However, prescribed grazing that incorporates periods of rest and recovery during the growing season will improve the vigor and gradual recovery of the more palatable tallgrasses and forbs. Prescribed burning is often necessary to maintain a grassland dominant community.

Community 1.3
Midgrass/Forbs

This plant community is dominated by a mixture of midgrasses and forbs. It occurs following many years of continuous overgrazing. Pastures are usually small and associated with farming enterprises. In the past they were often used as holding areas in anticipation of seasonal wheat pasture or other cropland forages. Major midgrasses are composite dropseed, sand dropseed, silver beardgrass, purpletop tridens, sideoats grama, western wheatgrass, and marsh bristlegrass. Shortgrasses that are present include Kentucky bluegrass, buffalograss, and blue grama. Major forbs on the site are Cuman ragweed, Canada goldenrod, Missouri goldenrod, white sagebrush, Carruth’s sagewort, white heath aster, annual marshelder, and annual ragweed. In some locations the site supports increasing amounts of shrubs and trees. The most common shrubs along drainways are desert false indigo, common buttonbush, roughleaf dogwood, and coralberry. Eastern cottonwood, black willow, peachleaf willow, American elm, and osage orange are the major trees found on the site. Shrubs and trees usually will not comprise over ten percent of total production. Although productivity is significantly reduced when compared to Reference Plant Community, this plant community can be managed as a stable community. Remnant plants of big bluestem, Indiangrass, switchgrass, prairie cordgrass, eastern gamagrass, and Maximilian sunflower are often found scattered throughout the site. Although usually grazed repeatedly and maintained in a low state of vigor, these plants respond favorably to periods of rest from grazing during the growing season and often regain vigor in a few years. The site may support increasing amounts of shrubs and trees in some areas. The common shrubs would include roughleaf dogwood, coralberry, and smooth sumac. Trees most often seen in this situation would include Siberian elm, common hackberry, and osage orange. These shrubs and trees may comprise 15 to 20 percent of the total production.

Resilience management. Recovery of the tallgrasses, midgrasses, and associated forbs characteristic of the Reference Plant Community will require many years of careful management that includes prescribed grazing and extended periods of rest and recovery during the growing season. If remnant stands of the desired species are not present or located nearby as seed sources for reestablishment, interseeding measures may be needed to create pioneer colonies for seed dispersal throughout the community. Prescribed burning can be a useful tool if used strategically to benefit the desired species, especially in the later stages of the recovery process that may take more than a decade.

Pathway 1.1 to 1.2
Community 1.1 to 1.2

These mechanisms include management controlled by repetitive heavy use, no rest or recovery of the key forage species, and no forage and animal balance for many extended grazing seasons. This type of management lasting for periods greater than 10 years will shift functional and structural plant group dominance towards a Tallgrass/Midgrass Plant Community. Annual burning or a fire frequency occurrence less than 2 years will cause a shift in community phases. The frequency of late spring annual burning in combination with late season rest may result in a shift in species diversity as well as fluctuations in productivity. Herbicide use every 1 to 3 years will remove legumes and forbs and become a grass dominated community. Drought conditions that persist more than 3 years with below average rainfall during the first half of the growing season in addition to inadequate rest provided for plant recovery will result in productivity changes.

Context dependence. Plant community composition shifts from Tallgrass to Tallgrass/Midgrass dominant.

Pathway 1.2 to 1.1
Community 1.2 to 1.1

Causes of plant community shift include management (10-15 years) with adequate rest and recovery of the key forage species (big bluestem, switchgrass, Indiangrass, and little bluestem) within the Reference Plant Community. If woody species are present, prescription fires every 6-8 years will be necessary for their removal and/or maintenance.

Pathway 1.2 to 1.3
Community 1.2 to 1.3

These mechanisms include management controlled by repetitive heavy use, no rest or recovery of the key forage species and no forage and animal balance for many extended grazing seasons. This type of management lasting for periods greater than 20 years will shift functional and structural plant group dominance towards a Midgrass/Forbs/Shortgrass Plant Community.

Pathway 1.3 to 1.2
Community 1.3 to 1.2

Causes of plant community shift include management (10-15 years) with adequate rest and recovery of the key forage species (little bluestem, sideoats grama, big bluestem, switchgrass, and Indiangrass) within the Midgrass/Tallgrass Plant Community. If woody species are present, prescription fires every 6-8 years will be necessary for their removal and/or maintenance.

State 2
Shortgrass State

With heavy, continuous grazing, blue grama and buffalograss will become the dominant species and have a sod-bound appearance. Unable to withstand the grazing pressure, only a remnant population of western wheatgrass remains.

Characteristics and indicators. The Shortgrass State is characterized with specific dynamic soil property changes. Changes between the Grassland State and the Shortgrass State has been documented. As plant community cover decreases from bunchgrasses to more of the sod grasses there is a decrease in infiltration and interception and an increase in surface runoff (Thurow T., 2003).

Resilience management. This is a resistant and resilient state. Grazing management practice should include a forage and animal balance.

Community 2.1
Shortgrass Plant Community

This plant community presents a distinctive shortgrass aspect on the landscape. It is dominated by blue grama and buffalograss with notable amounts of western wheatgrass and sideoats grama present. Other grasses include annual bromes, composite dropseed, Kentucky bluegrass, prairie threeawn, and tumble windmill grass. These species commonly account for 60 to 70 percent of the annual forage production. Like the desirable grasses, palatable legumes and other forbs have been reduced by continuous grazing and competition over many years. Prevalent broadleaf species in this situation include prairie broomweed, annual ragweed, white sagebrush, Cuman ragweed, interior ironweed, wavyleaf thistle, and curlycup gumweed. Forbs may comprise 15 to 25 percent of the total vegetation. This plant community often contains 15 to 20 percent woody species as a result of fewer fires and more opportunities for their encroachment. Eastern redcedar, smooth and/or fragrant sumac, roughleaf dogwood, and coralberry are representative trees and shrubs which occur on this site. Leadplant and Jersey tea may still be found, but are generally much reduced from their prominence in the Reference Plant Community.

Resilience management. This plant community can be managed as a stable shortgrass plant community. If recovery of the tallgrasses, midgrasses, and associated forbs characteristic of the Reference Plant Community is desired, however, many years of careful management that includes prescribed grazing and extended periods of rest during the growing season will be required. More study is necessary in order to document restoration processes to the Grassland State. This site may recover faster than adjoining ones as remnant plants may be somewhat protected by the steeper slopes and occasional surface rocks. Where remnant stands of the desired species are not available on or near the site, reseeding may be necessary to advance recovery. However, seeding or interseeding may be severely limited by the steepness of slope and occasional surface rocks.

State 3
Woody State

This state is dominated by a shrub and/or tree plant community. The increase and spread of shrubs and trees results from an absence of fire. Woody plants can increase up to 34% from a lack of fire according to a study from 1937 to 1969, in contrast to a 1% increase on burned areas (Bragg and Hulbert, 1976). Periodic burning will hinder the establishment of most woody species and favor forbs and grasses. However, it should be pointed out that not all unburned areas have a woody plant invasion. Birds, small mammals, and livestock are instrumental in the distribution of seed and accelerating the spread of most trees and shrubs common to this site. The speed of encroachment varies considerably and can occur on both grazed and non-grazed pastures. Many species of wildlife, especially bobwhite quail, turkey, and white-tailed deer benefit from the growth of trees and shrubs for both food and cover. When management for specific wildlife populations is desirable, these options should be considered in any brush management plan.

Characteristics and indicators. Hydrologic function is affected by the amount of vegetative cover. Canopy interception loss can vary from 25.4% to 36.7% (Thurow and Hester, 1997). A small rainfall event is usually retained in the foliage and does not reach the litter layer at the base of the tree. Only when canopy storage is reached and exceeded does precipitation fall to the soil surface. Interception losses associated with the accumulation of leaves, twigs, and branches at the bases of trees are considerably higher than losses associated with the canopy. The decomposed material retains approximately 40% of the water that is not retained in the canopy (Thurow and Hester, 1997). Soil properties affected include biological activity, infiltration rates, and soil fertility.

Resilience management. Special planning will be necessary to assure that sufficient amounts of fine fuel are available to carry fires with enough intensity to control woody species. In some locations the use of chemicals as a brush management tool may be desirable to initiate and accelerate this transition.

Community 3.1
Shrub and/or Tree Community

Shrubs and trees dominate this plant community and may produce 40 to 50 percent of the total vegetation. Major trees include eastern cottonwood, black willow, peachleaf willow, American elm, Siberian elm, common hackberry, and osage orange. More abundant shrubs are roughleaf dogwood, coralberry, smooth sumac, desert false indigo, and common buttonbush. The spread of these woody plants results from the absence of fire and may occur on the site regardless of grazing management. It is important to note, however, that not all unburned areas have a woody plant problem. Encroachment may occur on areas that have been overgrazed for years as well as on areas where both grazing and fire have been excluded. The speed and method of encroachment varies considerably but, under favorable conditions, can happen in as little as 20 to 30 years. Cottonwood, elm, and willow produce an abundance of seed that is distributed by wind over long distances. Common hackberry is spread by birds. Periodic burning tends to hinder establishment of most of these woody species and favor forbs and grasses. Where woody plants have invaded overgrazed areas, the understory vegetation is generally dominated by plants such as Kentucky bluegrass, composite dropseed, purpletop tridens, marsh bristlegrass, sedges, white sagebrush, interior ironweed, and white heath aster. Where woody plants have encroached onto areas that have gone essentially ungrazed for many years, the understory consists largely of big bluestem, Indiangrass, little bluestem, Virginia wildrye, Canada wildrye, sedges, prairie bundleflower, Canada goldenrod, and Maximilian sunflower. Herbage production is significantly reduced because of the tree and shrub competition for light and moisture. As such, grass yields vary from 30 to 40 percent of total vegetative production and forbs generally produce 5 to 10 percent of the total. Usually a prescribed burning program, accompanied with a plan of prescribed grazing, will return the plant community to one dominated by grasses and forbs. Special planning will be necessary to assure that sufficient amounts of fine fuel are available to carry fires with enough intensity to control woody species. Use of additional brush management tools such as chemicals or mechanical methods may be necessary to initiate and accelerate this transition in some locations.

Resilience management. Usually, a well-planned burning program accompanied by prescribed grazing will gradually return the plant community to one dominated by desirable grasses and forbs. Special planning will be necessary to assure that sufficient amounts of fine fuel are available to carry fires with enough intensity to control woody species. Use of labeled herbicides as a brush management tool will usually be necessary to reduce populations of fireresistant species like osage orange and honeylocust and accelerate the recovery of desired vegetative cover. Recently, some landowners have relied on the browsing habits of goats to suppress the woody growth.

State 4
Tillage State

Extensive areas of the historic Clay Lowland plant communities were plowed and converted to production of cultivated crops by the early European settlers and subsequent generations. In addition to destroying the original plant community, repeated tillage commonly resulted in major changes in soil conditions. Reductions in organic matter, mineral levels, soil structure, oxygen levels, and water holding capacity, along with increased runoff/erosion and shifts in the populations of soil-dwelling organisms, were common on these sites. The extent of these changes depended upon duration of cropping as well as crops grown and other management practices. The Tillage State consists of abandoned cropland that has been naturally revegetated (go-back) or planted/seeded to grassland. Many reseeded plant communities were planted with a local seeding mix under the Conservation Reserve Program (CRP) or were planted to a monoculture of sideoats grama. Go-back communities are difficult to define due to the variability of plant communities that can exist. Many of these communities are represented by the genus Aristida (threeawns).

Characteristics and indicators. This is an alternative state since the energy, hydrologic, and nutrient cycles are altered to that of the Reference State in its natural disturbance regime. Bulk density, aggregate stability, soil structure, and plant functional and structural groups are not fully restored to that of the Reference State. Mechanical tillage can destroy soil aggregation. Soil aggregates are an example of dynamic soil property change. Aggregate stability is critical for infiltration, root growth, and resistance to water and wind erosion (Brady and Weil, 2008).

Resilience management. This state is a result of a land use management decision.

Community 4.1
Reseed Plant Community

This plant community occurs on areas that were formerly farmed and reseeded with a mixture of native species common in the Reference Plant Community. Most seeding mixtures consisted of a blend of grasses that include sand bluestem, Indiangrass, switchgrass, little bluestem, sideoats grama, blue grama, and western wheatgrass. In some locations, seed of legumes and forbs such as prairie bundleflower and Maximilian sunflower were included in the mixture. Once these areas become fully established, production is comparable to that of the Reference Plant Community. Total annual production ranges varies according to the species planted, established plants, and years of establishment. When reseeded areas and areas supporting native rangeland exist in the same pasture, they seldom are utilized at the same intensity because domestic livestock usually prefer plants growing on the native rangeland areas. When feasible, reseeded plant communities should be managed as separate pastures or units. Some seeded areas are invaded by trees and shrubs during the establishment period of the desired plants. These invader species commonly include Siberian elm, common hackberry, eastern redcedar, eastern cottonwood, black willow, and roughleaf dogwood. Occasional burning is effective in controlling the establishment of these woody plants.

Resilience management. Following termination of cultivation, total annual production is quite variable and full recovery of the original plant community, including forbs and legumes, may take many decades. Additions of organic matter and minerals, rest and recovery from grazing, prescribed burning, and related management practices described earlier for this ecological site can be beneficial to the rehabilitation.

Community 4.2
Go-back Plant Community

This plant community also occurs on areas that were formerly farmed. When tillage operations ceased, the areas were allowed to revegetate or “go back” naturally in contrast to artificial reseeding to a selected species or group of species. The go-back process is a slow, gradual transformation that requires many years and many successional changes or stages in the plant community. The speed and extent of revegetation depends on the size of the area, level of grazing management and the proximity of the area to existing seed sources. In the initial stages of revegetation the site is usually dominated by annual forbs such as annual ragweed, slender snakecotton, Canadian horseweed, prairie sunflower, common sunflower, Mexican fireweed, camphorweed, and annual buckwheat. Gradually these are replaced by annual grasses including prairie threeawn, mat sandbur, tumblegrass, little barley, cheatgrass, and witchgrass. As plant succession progresses the plant community gradually becomes dominated by perennials. The major grasses include sand dropseed, composite dropseed, thin paspalum, purple lovegrass, red lovegrass, Scribner’s rosette grass, Carolina crabgrass, silver beardgrass, and tumble windmillgrass. Common forbs are Cuman ragweed, white sagebrush, Carruth’s sagewort, white heath aster, Missouri goldenrod, and sand milkweed. Combinations of these plants can form a stable community. In time with prescribed grazing management, other perennial grasses and forbs common in the Reference Plant Community return to the site. Blue grama is a shortgrass that is very common to the native plant communities on this site. However, it seldom occurs in go-back communities, even after 40 to 50 years of plant succession. Some go-back areas are invaded by trees and shrubs. The more common include elm, common hackberry, eastern redcedar, eastern cottonwood, and roughleaf dogwood. Occasional burning is effective in controlling these woody plants. Total annual production varies by site. This depends on seasonal precipitation and the stage of plant succession in the plant community.

Resilience management. Following termination of cultivation, total annual production is quite variable and full recovery of the original plant community, including forbs and legumes, may take many decades. Additions of organic matter and minerals, deferred grazing, prescribed burning, and related management practices described earlier for this ecological site can be beneficial to the rehabilitation.

State 5
Introduced, Invasive, Noxious State

This state includes three community phases which are characterized by the composition of plant species and soil functions that govern the ecological processes. These three plant communities occur and function independent of one another. Species that define this state include sericea lespedeza, caucasian bluestem, tall fescue, smooth brome, and Kentucky bluegrass. These species can and will invade rangelands without proactive control measures. sericea lespedeza and caucasian bluestem community phases are partially defined by the total production exceeding 15% by weight on a per acre basis. Tall fescue, smooth brome, and Kentucky bluegrass are partially defined by the total production exceeding 40% by weight on a per acre basis.

Characteristics and indicators. Ecological processes within this state that are affected and differ from the grassland state are hydrologic cycle and nutrient cycle. Water content and infiltration rates are affected by the species.

Resilience management. The plant communities that make up this state are sustained by fertilizing species and managing as pastureland or by a lack of treatment measures for individual species control, maintenance, and/or eradication.

Community 5.1
Caucasian Bluestem Community

Caucasian bluestem is the dominant species that govern the ecological processes and uses of this community. This species can and will invade rangelands without proactive control measures.

Resilience management. Caucasian bluestem survives all control measures. There is no way of killing the Caucasian bluestem without killing the native rangeland. There have been cases where the native taller grasses appear to shade and out compete the Caucasian bluestem but there are ungrazed places on the Konza Prairie Research and biological station where it was introduced from feeding livestock contaminated hay and where it now is crowding out the native grass as its spreads. Caucasian bluestem might be the most serious threat and most aggressive of the introduced, invasive, and noxious species of this time. Soil dynamic property changes include infiltration, biological activity, and soil fertility.

Community 5.2
Sericea Lespedeza Community

Sericea lespedeza (Lespedeza cuneata) is the dominant species that govern the ecological processes and uses of this community. Sericea lespedeza is invasive and a statewide noxious weed in Kansas. This species will quickly invade rangelands without proactive control measures. It competes with the native grass community with sunlight, water, and nutrients. It also produces allelopathic compounds (toxic chemicals that negatively impact the germination and/or growth of other plants).

Resilience management. Control measures for sericea lespedeza involve herbicide application. Follow recommended rates and chemical use according to Kansas State University Chemical Weed Control book. Conventional management practices such as prescribed grazing and fire have been less than effective in preventing the spread of sericea lespedeza in rangelands. Some suppression of sericea lespedeza has been observed after mowing or burning followed by intensive early stocking with stocker cattle. Goats will provide some control as they do eat it much more readily than cattle.

Community 5.3
Fescue, Brome, Bluegrass Community

Tall fescue, smooth brome, and Kentucky bluegrass are the dominant species that govern the ecological processes and uses of this community. Any one or combination of these species can be considered an invaded community at levels more than 40% by total weight annual production. Once these levels are reached management choices can change to favor these grasses and as a result land use is transitioned from rangeland to pastureland.

Resilience management. Inputs and energy in order to return species to a grassland state are greater than what is considered to be natural. Control measures for tall fescue, smooth brome, and Kentucky bluegrass might involve herbicide application and/or consecutive prescribed burns. Follow recommended rates and chemical use according to State extension guidelines such as Kansas State University Chemical Weed Control publication. Soil dynamic property changes include biological activity and soil fertility.

Transition 1 to 2
State 1 to 2

Long-term management (approximately 30 years) without a forage and animal balance and heavy, continuous grazing without adequate recovery periods between grazing events will convert the Grassland State to a Shortgrass State made up of blue grama and buffalograss sod. Drought in combination with this type of management will quicken the rate at which this transition occurs.

Constraints to recovery. The ecological processes affected are the hydrologic and nutrient cycles. There is an increase in evaporation rate, runoff, and in bulk density. There is a decrease in infiltration, a change in plant composition, and the functional and structural groups have changed dominance. These are all examples of the soil and vegetation properties that have compromised the resilience of the Grassland State and therefore transitioned to a Shortgrass State.

Transition 1 to 3
State 1 to 3

Changes from a Grassland State to a Woody State lead to changes in hydrologic function, forage production, dominant functional and structural groups, and wildlife habitat. Understory plants may be negatively affected by trees and shrubs by reductions in light, soil moisture, and soil nutrients. Increases in tree and shrub density and size have the effects of reducing understory plant cover and productivity, and desirable forage grasses often are most severely reduced (Eddleman, 1983). As vegetation cover changes from grasses to trees, a greater proportion of precipitation is lost throughout interception and evaporation; therefore, less precipitation is available for producing herbaceous forage or for deep drainage or runoff (Thurow and Hester, 1997).

Constraints to recovery. Recovery is possible through management.

Transition 1 to 4
State 1 to 4

This transition is triggered by a management action as opposed to a natural event. Tillage, or breaking the ground with machinery for crop production, will move the Grassland State to a Tillage State.

Constraints to recovery. The resilience of the Reference State has been compromised by the fracturing and blending of the native virgin sod. The energy, hydrologic, and nutrient cycles are altered and vary from that of the Grassland State.

Transition 1 to 5
State 1 to 5

Changes from a Grassland State to an introduced, invasive and/or noxious state can lead to changes in hydrology/erosion, forage production, wildlife habitat, and soil dynamic properties. These changes will vary depending on dominance of species. This transition is usually triggered by an introduction of non-native species. The source from which the species originated from (i.e. adjacent crop field) can usually but not always be detected. A threshold is crossed once the species (sericea lespedeza and Caucasian bluestem) is established and increases to levels of greater than 15% total annual production per acre. For cool season grasses such as tall fescue and smooth brome that level more than 40% total annual production per acre. Changes in species diversity reflect changes in soil biota activity. The introduced, invasive and noxious species are not selected and grazed and as a result become increasingly dominant. Hydrology changes begin to occur with the buildup of litter and interception rates increase as canopy increases.

Constraints to recovery. Need further research to document recovery processes.

Restoration pathway 3 to 1
State 3 to 1

Restoration efforts will be costly, labor-intensive, and can take many years, if not decades, to return to a Grassland State. Once canopy levels reach greater than 20 percent, estimated cost to remove trees is very expensive and includes high energy inputs. The technologies needed in order to go from an invaded Woody State to a Grassland State include but are not limited to: prescribed burning— the use of fire as a tool to achieve a management objective on a predetermined area under conditions where the intensity and extent of the fire are controlled; brush management— manipulating woody plant cover to obtain desired quantities and types of woody cover and/or to reduce competition with herbaceous understory vegetation, in accordance with overall resource management objectives; and prescribed grazing—the controlled harvest of vegetation with grazing or browsing animals managed with the intent to achieve a specified objective. In addition, to grazing at an intensity that will maintain enough cover to protect the soil and maintain or improve the quantity and quality of desirable vegetation. When a juniper tree is cut and removed, the soil structure and the associated high infiltration rate may be maintained for over a decade (Hester, 1996). This explains why the area near the dripline usually has substantially greater forage production for many years after the tree has been cut. It also explains why runoff will not necessarily dramatically increase once juniper is removed. Rather, the water continues to infiltrate at high rates into soils previously ameliorated by junipers, thereby increasing deep drainage potential. In rangeland, deep drainage amounts can be 16 percent of the total rainfall amount per year (Thurow and Hester, 1997).