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Ecological site R086AY011TX

Southern Blackland

Last updated: 9/21/2023
Accessed: 11/21/2024

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General information

Provisional. A provisional ecological site description has undergone quality control and quality assurance review. It contains a working state and transition model and enough information to identify the ecological site.

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Figure 1. Mapped extent

Areas shown in blue indicate the maximum mapped extent of this ecological site. Other ecological sites likely occur within the highlighted areas. It is also possible for this ecological site to occur outside of highlighted areas if detailed soil survey has not been completed or recently updated.

MLRA notes

Major Land Resource Area (MLRA): 086A–Texas Blackland Prairie, Northern Part

MLRA 86A, The Northern Part of Texas Blackland Prairie is entirely in Texas. It makes up about 15,110 square miles (39,150 square kilometers). The cities of Austin, Dallas, San Antonio, San Marcos, Temple, and Waco are located within the boundaries. Interstate 35, a major thoroughfare for commerce and travel, traverses the length of the MLRA from San Antonio to Dallas. The area supports tall and mid-grass prairies, but improved pasture, croplands, and urban development account for the majority of the acreage.

Classification relationships

USDA-Natural Resources Conservation Service, 2006.
-Major Land Resource Area (MLRA) 86A

Ecological site concept

The Blackland ecological site is a true tallgrass prairie. Reference sites show an intact grass community with small clumped dispersal of woody species. The soils are moderately deep to very deep, richly black in color, and characterized by their shrink-swell nature. The sites are widely distributed across the uplands and terraces throughout the region.

Associated sites

R086AY002TX	Southern Chalky Ridge The Chalky Ridge site is often upslope from the Blackland. It differs from the site by having shallow soils and low soil fertility.
R086AY004TX	Southern Claypan Prairie The Claypan Prairie site is often adjacent to the Blackland. It differs from the site by having a fine sandy loam surface soil layer over clay subsoils.
R086AY009TX	Southern Eroded Blackland The Eroded Blackland site is often adjacent to the Blackland site. It differs from the site by having extensive erosion indicated by a partial or lost A horizon, active rills and/or gullies, and lower production.
R086AY012TX	Loamy Bottomland The Southern Blackland site is often upslope from the Loamy Bottomland site. It differs from the Loamy Bottomland site by its position on uplands, high shrink-swell properties, and having clay soils and higher runoff.
R086AY013TX	Clayey Bottomland The Southern Blackland site is often upslope from the Clayey Bottomland site. It differs from the Clayey Bottomland site by its position on uplands, lack of high shrink-swell and hydric soil properties, and having clay soils and higher runoff.

Similar sites

R086AY009TX	Southern Eroded Blackland The Eroded Blackland site is similar to the Blackland site by having similar soil types and topography. It differs from the site by having extensive erosion indicated by a partial or lost A horizon, active rills and/or gullies, and lower production.
R086AY010TX	Northern Blackland The Northern Blackland site is similar to the Southern Blackland site by having similar physiographic features and representative soil features. It differs from the site by receiving more effective precipitation.

R086AY009TX

Southern Eroded Blackland

The Eroded Blackland site is similar to the Blackland site by having similar soil types and topography. It differs from the site by having extensive erosion indicated by a partial or lost A horizon, active rills and/or gullies, and lower production.

R086AY010TX

Northern Blackland

The Northern Blackland site is similar to the Southern Blackland site by having similar physiographic features and representative soil features. It differs from the site by receiving more effective precipitation.

Table 1. Dominant plant species

Tree	Not specified
Shrub	Not specified
Herbaceous	(1) Andropogon gerardii (2) Tripsacum dactyloides

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Physiographic features

These are uplands and terraces with nearly level to moderate slopes. Slope gradients range from 0 to 8 percent but are usually less than 5 percent. There is no flooding or ponding with a low to high runoff, greatly depending on soil saturation and slope.

Table 2. Representative physiographic features

Landforms	(1) Plains > Terrace (2) Plains > Ridge > Gilgai
Runoff class	Low to high
Flooding frequency	None
Ponding frequency	None
Elevation	300 – 600 ft
Slope	5%
Water table depth	60 – 80 in
Aspect	Aspect is not a significant factor

Table 3. Representative physiographic features (actual ranges)

Runoff class	Not specified
Flooding frequency	Not specified
Ponding frequency	Not specified
Elevation	Not specified
Slope	8%
Water table depth	Not specified

Climatic features

The climate for MLRA 86A is humid subtropical and is characterized by hot summers, especially in July and August, and relatively mild winters. Tropical maritime air controls the climate during spring, summer and fall. In winter and early spring, frequent surges of Polar Canadian air cause sudden drops in temperatures and add considerable variety to the daily weather. When these cold air masses stagnate and are overrun by moist air from the south, several days of cold, cloudy, and rainy weather follow. Generally, these occasional cold spells are of short duration with rapid clearing following cold frontal passages. The summer months have little variation in day-to-day weather except for occasional thunderstorms that dissipate the afternoon heat. The moderate temperatures in spring and fall are characterized by long periods of sunny skies, mild days, and cool nights. The average relative humidity in mid-afternoon is about 60 percent. Humidity is higher at night, and the average at dawn is about 80 percent. The sun shines 75 percent of the time during the summer and 50 percent in winter. The prevailing wind direction is from the south and highest wind speeds occur during the spring months. Rainfall during the spring and summer months generally falls during thunderstorms, and fairly large amounts of rain may fall in a short time. High-intensity rains of short duration are likely to produce rapid runoff almost anytime during the year. The predominantly anticyclonic atmospheric circulation over Texas in summer and the exclusion of cold fronts from North Central Texas result in a decrease in rainfall during midsummer. The amount of rain that falls varies considerably from month-to-month and from year-to-year.

Table 4. Representative climatic features

Frost-free period (average)	244 days
Freeze-free period (average)	276 days
Precipitation total (average)	36 in

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Figure 2. Monthly precipitation range

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Figure 3. Monthly average minimum and maximum temperature

Figure 4. Annual precipitation pattern

Figure 5. Annual average temperature pattern

Climate stations used

(1) LULING [USC00415429], Luling, TX
(2) TAYLOR 1NW [USC00418862], Taylor, TX
(3) TEMPLE [USC00418910], Temple, TX
(4) CAMERON [USC00411348], Cameron, TX
(5) CEDAR CREEK 5 S [USC00411541], Cedar Creek, TX
(6) GRANGER DAM [USC00413686], Granger, TX
(7) RED ROCK [USC00417497], Red Rock, TX
(8) SAN ANTONIO INTL AP [USW00012921], San Antonio, TX
(9) AUSTIN BERGSTROM AP [USW00013904], Austin, TX
(10) SAN MARCOS [USC00417983], San Marcos, TX
(11) AUSTIN-CAMP MABRY [USW00013958], Austin, TX
(12) NEW BRAUNFELS [USC00416276], New Braunfels, TX
(13) SAN ANTONIO 8NNE [USC00417947], San Antonio, TX
(14) WACO DAM [USC00419417], Waco, TX

Soil features

The site consists of moderately deep to very deep, moderately well to well drained soils that are slow to very slowly permeable. The upland soils formed in calcareous marl and marine sediments, high in smectitic clays. The terrace soils formed in clayey alluvial sediments. A few of the upland soils may have weathered and soft bedrock at a depth of more than 24 inches below the soil surface. The majority of this site is used for cropland due to the very deep, highly productive soils. There are some areas that are used for pasture or rangeland.

In a representative profile, the surface layer is black clay about 24 inches thick. The clay extends below 24 inches and to depths of more than 80 inches. The subsoil is clay that grades from very dark gray to light olive brown as depth increases. Available water capacity to a depth of 60 inches is moderate, and shrink swell potential is very high.

The dominant associated soil series for the Blackland ecological site includes: Barbarosa, Behring, Branyon, Burleson, Fairlie, Greenvine, Heiden, and Houston Black.

Table 5. Representative soil features

Parent material	(1) Residuum – mudstone (2) Alluvium – mudstone
Surface texture	(1) Clay (2) Gravelly clay (3) Stony clay
Family particle size	(1) Clayey
Drainage class	Moderately well drained to well drained
Permeability class	Slow to very slow
Soil depth	24 – 80 in
Surface fragment cover <=3"	40%
Surface fragment cover >3"	10%
Available water capacity (0-40in)	5 – 11 in
Calcium carbonate equivalent (0-40in)	55%
Electrical conductivity (0-40in)	4 mmhos/cm
Sodium adsorption ratio (0-40in)	2
Soil reaction (1:1 water) (0-40in)	5.6 – 8.4
Subsurface fragment volume <=3" (Depth not specified)	25%
Subsurface fragment volume >3" (Depth not specified)	15%

Ecological dynamics

Introduction – The Northern Blackland Prairies are a temperate grassland ecoregion contained wholly in Texas, running from the Red River in North Texas to San Antonio in the south. The region was historically a true tallgrass prairie named after the rich dark soils it was formed in. Other vegetation included deciduous bottomland woodlands along rivers and creeks.

Background – Natural vegetation on the uplands is predominantly tall warm-season perennial bunchgrasses with lesser amounts of midgrasses. This tallgrass prairie was historically dominated by big bluestem (Andropogon gerardii), Indiangrass (Sorghastrum nutans), switchgrass (Panicum virgatum), eastern gamagrass (Tripsacum dactyloides), and little bluestem (Schizachyrium scoparium). Midgrasses such as sideoats grama (Bouteloua curtipendula), Virginia wildrye (Elymus virginicus), Florida paspalum (Paspalum floridanum), Texas wintergrass (Nassella leucotricha), hairy grama (Bouteloua hirsuta), and dropseeds (Sporobolus spp.) are also abundant in the region. A wide variety of forbs add to the diverse native plant community. Mottes of live oak (Quercus virginiana) and hackberry (Celtis spp.) trees are also native to the region. In some areas, cedar elm (Ulmus crassifolia), eastern red cedar (Juniperus virginiana), and honey locust (Gleditsia triacanthos) are abundant. In the Northern Blackland Prairie oaks (Quercus spp.) are common increasers, but in the Southern Blackland Prairie oaks are less prevalent. Junipers are common invaders, particularly in the northern part of the region.

During the first half of the nineteenth century, row crop agriculture lead to over 80 percent of the original vegetation lost. During the second half, urban development has caused even an even greater decline in the remaining prairie. Today, less than one percent of the original tallgrass prairie remains. The known remaining blocks of intact prairie range from 10 to 2,400 acres. Some areas are public, but many are privately owned and have conservation easements.

Current State – Much of the area is classified as prime farmland and has been converted to cropland. Most areas where native prairie remains have histories of long-term management as native hay pastures. Tallgrasses remain dominant when haying of warm-season grasses is done during the dormant season or before growing points are elevated, meadows are not cut more than once, and the cut area is deferred from grazing until frost.

Due to the current-widespread farming, the Northern Blackland Prairie is still relatively free from the invasion of brush that has occurred in other parts of Texas. In contrast, many of the more sloping have experienced heavy brush encroachment, and the continued increase of brush encroachment is a concern. The shrink-swell and soil cracking characteristics of the soils favor brush species with tolerance for soil movement.

Current Management – Rangeland and pastureland are grazed primarily by beef cattle. Horse numbers are increasing rapidly in the region, and in recent years goat numbers have increased significantly. There are some areas where dairy cattle, poultry, goats, and sheep are locally important. Whitetail deer, wild turkey, bobwhite quail, and dove are the major wildlife species, and hunting leases are a major source of income for many landowners in this area.

Introduced pasture has been established on many acres of old cropland and in areas with deeper soils. Coastal bermudagrass (Cynodon dactylon) and kleingrass (Panicum coloratum) are by far the most frequently used introduced grasses for forage and hay. Hay has also been harvested from a majority of the prairie remnants, where long-term mowing at the same time of year has possibly changed the relationships of the native species. Cropland is found in the valleys, bottomlands, and deeper upland soils. Wheat (Triticum spp.), oats (Avena spp.), forage and grain sorghum (Sorghum spp.), cotton (Gossypium spp.), and corn (Zea mays) are the major crops in the region.

Fire Regimes – The prairies were a disturbance-maintained system. Prior to European settlement (pre-1825), fire and infrequent, but intense, short-duration grazing by large herbivores (mainly bison and to a lesser extent pronghorn antelope) were important natural landscape-scale disturbances that suppressed woody species and invigorated herbaceous species (Eidson and Smeins 1999). The herbaceous prairie species adapted to fire and grazing disturbances by maintaining below-ground penetrating tissues. Wright and Bailey (1982) report that there are no reliable records of fire frequency occurring in the Great Plains grasslands because there are no trees to carry fire scars from which to estimate fire frequency. Because prairie grassland is typically of level or rolling topography, a natural fire frequency of 5 to 10 years seems reasonable.

Disturbance Regimes - Precipitation patterns are highly variable. Long-term droughts, occurring three to four times per century, cause shifts in species composition by causing die-off of seedlings, less drought-tolerant species, and some woody species. Droughts also reduce biomass production and create open space, which is colonized by opportunistic species when precipitation increases. Wet periods allow tallgrasses to increase in dominance. These natural disturbances cause shifts in the states and communities of the ecological sites.

State and transition model

More interactive model formats are also available. View Interactive Models
Click on state and transition labels to scroll to the respective text

Ecosystem states

1. Grassland

2. Shrubland

3. Converted

T1A	-	No fire, no brush management, improper grazing management, drought
T1B	-	Brush management, crop cultivation, pasture planting, nutrient management, pest management
R2A	-	Fire, brush management, proper grazing, range planting
T2A	-	Brush management, crop cultivation, pasture planting, nutrient management, pest management
R3A	-	Fire, brush management, proper grazing, range planting
T3A	-	No fire, no brush management, heavy continuous grazing, no pest management

State 1 submodel, plant communities

1.1. Tallgrass Prairie

1.2. Midgrass Prairie

1.1A	-	No fire, no brush management, improper grazing management, drought
1.2A	-	Fire, brush management, proper grazing

State 2 submodel, plant communities

2.1. Mixed-Grass/Mixed-Brush

2.2. Mixed Brush

2.3. Woodland

2.1A	-	No fire, no brush management, improper grazing management, drought
2.2A	-	Fire, brush management, proper grazing, range planting
2.2B	-	No fire, no brush management, improper grazing management, drought
2.3A	-	Fire, brush management, proper grazing, range planting

State 3 submodel, plant communities

3.1. Converted Land

3.2. Go-Back Land

3.1A	-	No fire, no brush management, heavy continuous grazing, no pest management
3.2A	-	Fire, brush management, proper grazing, pest management

State 1
Grassland

Two communities exist in the Grassland State: the 1.1 Tallgrass Prairie Community and the 1.2 Midgrass Plant Community. Community 1.1 is characterized by tallgrasses dominating the understory and comprising greater than 50 percent of the annual production. Woody species cover less than 10 percent of the area. Community 1.2 is characterized by greater than 50 percent annual production from grasses, but the woody species cover is 10 to 35 percent, with some species attaining heights of three feet.

Community 1.1
Tallgrass Prairie

The Tallgrass Prairie Plant Community (1.1) is the reference community. It is characterized by deeper soils dominated by warm-season, perennial tallgrasses, with warm-season, perennial midgrasses filling most of the remaining species composition. The warm-season, perennial forb component varies between 5 and 15 percent depending on climatic patterns and local precipitation. Woody species make up a minor component of the community, five percent by weight, even in the short-term absence of fire (two to five years). Indiangrass, big bluestem, eastern gamagrass, and switchgrass dominate the site. Little bluestem and Florida paspalum act as increasers when improper grazing management causes less grazing tolerant grasses to lose vigor. Other important grasses included Virginia wildrye, sideoats grama, silver bluestem (Bothriochloa laguroides), Texas wintergrass, and Texas cupgrass (Eriochloa sericea). Forbs commonly found on the site include Engelmann’s daisy (Engelmannia peristenia), Maximilian sunflower (Helianthus maximiliani), blacksamson (Echinacea angustifolia), button snakeroot (Eryngium yuccifolium), halfshrub sundrop (Calylophus serrulatus), sensitive-briar (Mimosa spp.), and yellow neptunia (Neptunia lutea). Typical but infrequent shrub and tree species include species of oak, hackberry, and elm (Ulmus spp.), along with bumelia (Sideroxylon spp.) and coralberry (Symphoricarpos orbiculatus). The reference grassland community will transition to a midgrass-dominated community under the stresses of improper grazing management. The first species to decrease in dominance will be the most palatable and/or least grazing tolerant grasses and forbs (e.g. eastern gamagrass, switchgrass, Indiangrass, big bluestem, and Engelmann’s daisy). This will initially result in an increase in composition of little bluestem and Florida paspalum. If improper grazing management continues, little bluestem and Florida paspalum will decrease and midgrasses such as silver bluestem and sideoats grama will increase in composition. Less palatable forbs will increase at this stage. Because the woody species that dominate in the Shrubland State are native species that occur as part of the Grassland State, the transition to the Shrubland State is a linear process with shrubs starting to increase soon after fire or brush control. Unless some form of brush control takes place, woody species will increase to the 35 percent canopy cover level that indicates a state change. This is a continual process that is always in effect. Managers need to detect the increase in woody species when canopy is less than 35 percent and take management action before the state change occurs. There is not a 10-year window before shrubs begin to increase followed by a rapid transition to the Shrubland State. The drivers of the transition (lack of fire and lack of brush control) constantly pressure the system towards the Shrubland State. Canopy cover drives the transitions between community and states because of the influence of shade and interception of rainfall. Species composition by weight remains an important descriptor of the herbaceous community and of the community as a whole. Woody species are included in species composition for the site. This plant community has very little bare ground. Plant basal cover and litter make up almost 100 percent ground cover. Infiltration is rapid and runoff is very low when the soils are dry and open. Once soils have swelled to the point of sealing shut, infiltration is slow and runoff can occur. Soils with heavy plant cover contribute to increasing organic matter and soil building. The nearly level areas have gilgai. Sloping soils also have gilgai which create microridges and valleys extending up and down the slopes. Soil erosion is very low if tallgrasses and the water trapping gilgai are present. As much as six inches of water could be temporarily trapped in these gilgai microreliefs before runoff begins. Plowing removes the gilgai; it may take 20 years or more after plowing stops for the gilgai to reform.

Figure 6. Annual production by plant type (representative values) or group (midpoint values)

Table 6. Annual production by plant type

Plant type	Low (lb/acre)	Representative value (lb/acre)	High (lb/acre)
Grass/Grasslike	3200	4400	5600
Forb	600	825	1050
Shrub/Vine	200	275	350
Total	4000	5500	7000

Community 1.2
Midgrass Prairie

The Midgrass Prairie Plant Community (1.2) is the result of improper cattle grazing management or improper haying practices over a long period of time. Tallgrasses in the reference community decrease in vigor and production, allowing midgrasses and forbs to increase to the point that they make up more than 50 percent of species composition. Indigenous or invading woody species may increase depending on fire and brush control methods. In the Tallgrass Prairie Community (1.1), repeated fires and competition from a vigorous grass component keep woody canopy cover low. When the Midgrass Prairie Plant Community (1.2) is continually overgrazed and fire is excluded, the community crosses a threshold to the Grass/Mixed-Brush Plant Community (2.1) that is dominated by woody plants. Important grasses found in this community include little bluestem, sideoats grama, silver bluestem, paspalums, Texas wintergrass, and tridens (Tridens spp.). Some of the reference community perennial forbs persist, but less palatable forbs will increase. Woody canopy may be as high as 35 percent, depending on the type of grazing animal, fire interval, brush control, and/or availability of increaser shrub species. Numerous shrub and tree species will encroach because overgrazing by livestock has reduced grass cover, exposed more soil, and reduced grass fuel for fire. Typically, trees such as oak, elm, and hackberry will increase in size, while other woody species such as honey mesquite (Prosopis glandulosa), bumelia, coralberry, honey locust and elbowbush (Forestiera pubescens) will increase in density. Aggressive, introduced pasture species may begin to invade the Midgrass Prairie Community, particularly if they have been seeded in nearby pastures. These include introduced paspalums, such as bahiagrass (Paspalum notatum), Old World bluestems (Bothriochloa spp.), and Johnsongrass (Sorghum halepense). Heavy continuous grazing will reduce plant cover, litter, and mulch. Bare ground will increase and expose the soil to crusting and erosion. Some mulch and litter movement may occur during rainstorms, but little soil movement occurs due to gentle slopes in this vegetation type. Litter and mulch will move off site as plant cover declines. Increasing woody dominants are oak, hackberry, elm, juniper, and honey mesquite. Once shrubs reach a height of about three feet, they become more resistant to being killed by fires. When woody species exceed 35 percent canopy cover, the site crosses a threshold (T1A) into the Shrubland State (2) and the Grass/Mixed-Brush Plant Community (2.1). Until the Midgrass Prairie Plant Community (1.2) crosses the threshold into the Grass/Mixed-Brush Community (2.1), this community can be managed back toward the reference community (1.1) through the use of cultural practices including prescribed grazing, prescribed burning, and strategic brush control. It may take several years to achieve this, depending upon climate and the aggressiveness of the manager. Once woody species begin to establish, returning fully to the reference community is difficult, but it is possible to return to a similar plant community. If improper grazing management continues but shrubs are held in check through fire, brush control, browsing, or mowing, the Midgrass Prairie Plant Community will continue to degrade. Tallgrasses will continue to decrease in species composition, and midgrasses will begin to decrease. Grazing-resistant shortgrasses, annuals, and forbs will represent more of species composition. These species may increase in relative composition due to the loss of tall and midgrasses. The site will have reduced production and poor ecological processes.

Figure 7. Annual production by plant type (representative values) or group (midpoint values)

Table 7. Annual production by plant type

Plant type	Low (lb/acre)	Representative value (lb/acre)	High (lb/acre)
Grass/Grasslike	1800	2400	3000
Forb	600	800	1000
Shrub/Vine	600	800	1000
Total	3000	4000	5000

Pathway 1.1A
Community 1.1 to 1.2

Tallgrass Prairie

Midgrass Prairie

The Tallgrass Prairie Plant Community will shift to the Midgrass Prairie Plant Community when there is continued growing-season stress on reference grass species. These stresses include improper grazing management that creates insufficient critical growing-season deferment, excess intensity of defoliation, repeated, long-term growing-season defoliation, long-term drought, and/or other repeated critical growing-season stress. Increaser species (midgrasses and woody species) are generally endemic species released by disturbance. Woody species canopy exceeding 20 percent and/or dominance of tallgrasses falling below 50 percent of species composition indicate a transition to the Midgrass Prairie Plant Community. The reference community can be maintained through implementation of brush management combined with properly managed grazing that provides adequate growing-season deferment to allow establishment of tall grass propagules and/or the recovery of vigor of stressed plants. The driver for community shift 1.1A for the herbaceous component is improper grazing management. The driver for the woody component is lack of fire and/or brush control.

Pathway 1.2A
Community 1.2 to 1.1

Midgrass Prairie

Tallgrass Prairie

The Midgrass Prairie Plant Community will return to the Tallgrass Prairie Plant Community under grazing management that provides sufficient critical growing-season deferment in combination with proper grazing intensity. Favorable moisture conditions will facilitate or accelerate this transition. The understory component may return to dominance by tallgrasses in the absence of fire or brush control. However, reduction of the woody component to 10 percent or less canopy cover will require inputs of fire or brush control. The understory and overstory components can act independently when canopy cover is less than 35 percent. Meaning, an increase in shrub canopy cover can occur while proper grazing management creates an increase in desirable herbaceous species. The driver for community shift 1.2A for the herbaceous component is proper grazing management. The driver for the woody component is fire and/or brush control.

State 2
Shrubland

The Shrubland State has three communities: 2.1 Mixed-Grass/Mixed-Brush Community, 2.2 Mixed-Brush Community, and 2.3 Woodland Community. The 2.1 community has a woody species overstory canopy of 35 to 50 percent, the 2.2 community over 50 percent, and the 2.3 community has a closed canopy. As tree and brush canopy increases, the herbaceous understory production decreases due to lack of light availability.

Community 2.1
Mixed-Grass/Mixed-Brush

The Grass/Mixed-Brush Plant Community (2.1) presents a 35 to 50 percent woody plant canopy, with oak, hackberry, elm, mesquite, or juniper as dominant woody species. This community can occur as a result of continuous improper grazing management combined with lack of fire or brush control. It can also occur where there has been proper grazing management without brush control or fire. Improper grazing management speeds the process. Although it is rarely found, it is possible for the herbaceous component to include substantial production from tallgrasses. Palatable woody species tend to decrease and unpalatable woody species tend to increase, particularly where there is heavy browsing from deer or goats. Honey mesquite is an early increaser throughout the MLRA. Ashe juniper (Juniperus ashei) invaded from the south, and eastern red cedar is found more frequently in the northern portion of the MLRA. Many of the reference (1.1) shrubs are still present. Sideoats grama and other reference (1.1) midgrasses decrease, but still remain the dominant component of composition, while shortgrasses such as buffalograss (Bouteloua dactyloides) increase. Remnants of the reference community (1.1) grasses and forbs along with unpalatable invaders occupy the interspaces between shrubs. Cool-season species such as Texas wintergrass and sedges (Carex spp.), plus other grazing-resistant species, can be found under and around woody plants. Plant vigor and productivity of the grassland component is reduced due to grazing pressure and competition for sunlight, nutrients, and water from woody plants. Common herbaceous species include threeawns (Aristada spp.), dropseeds, and dotted gayfeather (Liatris punctata). Tumblegrass (Schedonnardus paniculatus), Texas grama (Bouteloua rigidiseta), western ragweed (Ambrosia psilostachya), Indian paintbrush (Castilleja spp.), Texas bluebonnet (Lupinus texensis), curly-mesquite (Hilaria belangeri), and annual species are persistent increasers until shrub density reaches maximum canopy. This community can dominated by a mix of forbs and short stature shrubs when there is continued growing season stress on reference and midgrass species. This transition usually results from heavy, long-term continuous grazing and is often associated with farm lots and horse pastures. Invasive species often dominate the site, including invasive forbs, shrubs, and grasses. As the grassland vegetation declines, more soil is exposed, leading to crusting and erosion. In this vegetation type, erosion can be severe. Higher rainfall interception losses by the increasing woody canopy combined with evaporation and runoff can reduce the effectiveness of rainfall. Soil organic matter and soil structure decline within the interspaces, but soil conditions improve under the woody plant cover. Some soil loss can occur during rainfall events. Annual primary production is approximately 2,000 to 4,500 pounds per acre. In this plant community, annual production is balanced between herbaceous plants and woody species, with herbaceous production still the dominant component of annual production. Browsing animals such as goats and deer can find fair food value if browse plants have not been grazed excessively. Forage quantity and quality for cattle is low. Unless brush management and good grazing management are applied at this stage, woody species canopy will exceed 50 percent, causing the community to convert to the Mixed-Brush Plant Community (2.2). The trend cannot be reversed with proper grazing management alone.

Figure 8. Annual production by plant type (representative values) or group (midpoint values)

Table 8. Annual production by plant type

Plant type	Low (lb/acre)	Representative value (lb/acre)	High (lb/acre)
Shrub/Vine	800	1300	1800
Grass/Grasslike	800	1300	1800
Forb	400	650	900
Total	2000	3250	4500

Community 2.2
Mixed Brush

The Mixed-Brush Plant Community (2.2) has 50 to 80 percent woody canopy cover and is the result of many years of improper grazing, lack of periodic fires, and/or a lack of proper brush management. Reference community woody species or increasers such as honey mesquite and/or juniper dominate the Mixed-Brush Plant Community (2.2). The site can now have the appearance of a dense shrubland or savannah of interspersed shrubland and grassland areas. Common understory shrubs are pricklypear (Opuntia spp.), agarito (Mahonia trifoliolata), and sumac (Rhus spp.). Woody shrubs seem to increase more rapidly in the southern portion of the site. With continued lack of brush control, the trees and shrubs can exceed 80 percent canopy cover, which indicates the transition to the Woodland Community (2.3). Remnant midgrasses and opportunistic shortgrasses, annuals, and perennial forbs occupy the woody plant interspaces. Characteristic grasses are curly-mesquite, buffalograss, and tumblegrass. Texas wintergrass and annuals are found in and around tree/shrub cover. Grasses and forbs make up 50 percent or less of the annual herbage production. Common forbs include dotted gayfeather, halfshrub sundrop, croton, western ragweed, verbena (Verbena spp.), snow-on-the-prairie (Euphorbia bicolor), Mexican sagewort (Artemisia ludoviciana ssp. mexicana), and sensitive-briar. The shrub canopy acts to intercept rainfall and increase evapotranspiration losses, creating a more xeric microclimate. Soil fauna and organic mulch are reduced, exposing more of the soil surface to erosion in interspaces. The exposed soil crusts readily. However, within the woody canopy, hydrologic processes stabilize and soil organic matter and mulch begin to increase and eventually stabilize under the shrub canopy. The Mixed-Brush Plant Community (2.2) can provide good cover habitat for wildlife, but only limited forage or browse is available for livestock or wildlife. At this stage, highly intensive restoration practices are needed to return the shrubland to grassland. Alternatives for restoration include brush control and range planting with proper stocking, prescribed grazing, and prescribed burning following restoration to maintain the desired community.

Figure 9. Annual production by plant type (representative values) or group (midpoint values)

Table 9. Annual production by plant type

Plant type	Low (lb/acre)	Representative value (lb/acre)	High (lb/acre)
Shrub/Vine	1050	1400	1750
Grass/Grasslike	225	300	375
Forb	225	300	375
Total	1500	2000	2500

Community 2.3
Woodland

The Woodland Community (2.3) has more than 80 percent woody canopy cover as the result of lack of periodic fires, and/or a lack of proper brush management. Reference woody species or increasers such as honey mesquite and/or juniper dominate the Woodland Community (2.3) with little herbaceous understory. The site has the appearance of a dense shrubland or woodland. Herbaceous understory plants are limited to shade-tolerant grasses, sedges, and forbs. Under the woody canopy, hydrologic processes stabilize, and soil organic matter and mulch begin to increase and eventually stabilize under the shrub canopy. The Woodland Community (2.3) can provide good habitat for wildlife that favor woodland habitat. Highly intensive restoration practices are needed to return the woodland to grassland. Alternatives for restoration include brush control and range planting with proper stocking, prescribed grazing, and prescribed burning following restoration to maintain the desired community.

Figure 10. Annual production by plant type (representative values) or group (midpoint values)

Table 10. Annual production by plant type

Plant type	Low (lb/acre)	Representative value (lb/acre)	High (lb/acre)
Shrub/Vine	1800	2700	3600
Forb	150	225	300
Grass/Grasslike	50	75	100
Total	2000	3000	4000

Pathway 2.1A
Community 2.1 to 2.2

Without some form of brush control, woody density and canopy cover will increase in the Grass/Mixed-Brush Plant Community until it converts into the Mixed-Brush Plant Community. Improper grazing management and/or long-term drought (or other growing season stress) will accelerate this transition. Woody species canopy exceeding 50 percent indicates this transition. Herbaceous understory may be similar to any of the Grassland State Plant Communities. Improper grazing or other long-term growing season stress can increase the composition of less productive grasses and low-growing (or unpalatable) forbs in the herbaceous component. Even with proper grazing, in the absence of fire the woody component will increase to the point that the herbaceous component will decline in production and shift in composition toward sedges, grasses, and forbs suited to growing in shaded conditions with reduced available soil moisture. The driver for community shift 2.1A is lack of fire and/or brush control.

Pathway 2.2A
Community 2.2 to 2.1

Brush management and/or fire can reduce the woody component of the Mixed-Brush Plant Community to below the transition level of 50 percent brush canopy. Continued fire and/or brush management will be required to maintain woody density and canopy below 50 percent. If the herbaceous component has transitioned to shortgrasses and low forbs, proper grazing management (combined with favorable moisture conditions and adequate seed source) will be necessary to facilitate the shift of the understory component in the Mixed-Brush Plant Community to a midgrass-dominated Grass/Mixed-Brush Plant Community. Range planting may accelerate the transition of the herbaceous community, particularly when combined with favorable growing conditions. Range planting is more commonly associated with restoration efforts associated with Restoration Pathway R2A. The driver for community shift 2.2A is fire and/or brush control.

Pathway 2.2B
Community 2.2 to 2.3

Without fire (natural or human-caused) and/or brush control, woody density and canopy cover will increase in the Mixed-Brush Plant Community until it converts into the Woodland Community. Woody species canopy exceeding approaching closed canopy (greater than 80 percent) and a decline of herbaceous understory species composition of less than 20 percent indicate this transition. Herbaceous understory will be sparse and comprised of sedges, grasses, and forbs suited to growing in shaded conditions with reduced available soil moisture. The driver for community shift 2.2B is lack of fire and/or brush control.

Pathway 2.3A
Community 2.3 to 2.2

Brush management and/or fire can reduce the woody component of the Woodland Community below the transition level of 80 percent woodland canopy. Continued fire and/or brush management will be required to maintain woody density and canopy below 80 percent. Range planting may accelerate the transition of the herbaceous community, particularly when combined with favorable growing conditions. Range planting is more common with restoration efforts associated with Restoration Pathway R2A. The driver for community shift 2.3A is removal of canopy cover to allow limited recovery of understory species.

State 3
Converted

Two communities exist in the Converted State: 3.1 Converted Land Community and the 3.2 Go-Back Land Community. The 3.1 Community is characterized by agricultural production. The site may be planted to improved pasture for hay or grazing. The site may otherwise be planted to row crops. The 3.2 community represents an agricultural state that has not been managed. The land is colonized by first successional species.

Community 3.1
Converted Land

The Converted State (3) occurs when the prairie, either the Grassland State (1) or Shrubland State (2), is plowed for planting to cropland, hayland, tame pasture, or use as non-agricultural land. The Converted State includes cropland, tame pasture, and go-back land. Agronomic practices are used to convert rangeland to the Converted State and to make changes between the communities in the Converted State. Many or all native species are replaced by seeding crops or introduced species into the plowed soil. The native component of the prairie is usually lost in this state, and even with reseeding, the ecological processes defining the past states of the site can be permanently changed. Common introduced species include coastal Bermudagrass and kleingrass, which are used in hayland and tame pastures. Wheat, oats, forage sorghum, grain sorghum, cotton, and corn are the major crop species. Cropland and tame pasture require repeated and continual inputs of fertilizer and weed control to maintain the Converted State. Without agronomic inputs, the site will eventually return to either the Grassland or Shrubland State. Weed and shrub control will be required because seeds remain in the soil or are transported to the site. Return to native prairie communities in the Grassland State is more likely to be successful if soil chemistry and structure have not been severely altered. Preservation of favorable soil microbes increases the likelihood of a return to reference conditions. Restoration to native prairie will require seedbed preparation and seeding of native species. Without active restoration the site is not likely to return to reference conditions due to the presence of introduced forbs and grasses. Protocols and plant materials for restoring prairie communities are a developing portion of restoration science.

Community 3.2
Go-Back Land

Without agronomic inputs, the site will eventually return to either the Grassland or Shrubland State. The site is considered go-back land when active management for pasture ceases. Heavily disturbed soils usually return to the Shrubland State but could return to a Grassland State if shrub seeds are not present. Long-term cropping creates changes in soil chemistry, microflora and structure that make restoration to the reference state very difficult and/or expensive. Moreover, the residual seedbank is usually depleted depending upon the length of time the site has been in the converted state. Restoration to near native prairie is possible. It will nearly always require seedbed preparation, suppression of shrubs and seeding of native species. Otherwise, it would take a very long time to reestablish from natural processes. Protocols and plant materials for restoring prairie communities are a developing portion of restoration science.

Pathway 3.1A
Community 3.1 to 3.2

Converted Land

Go-Back Land

The driver for this transition is lack of agricultural management. Without practices to suppress forbs and woody species, the land will eventually grow first successional species. Annual forbs and grasses are common colonizers and first provide ground cover and soil stability. Eventually, woody species will encroach and begin rapid expansion.

Pathway 3.2A
Community 3.2 to 3.1

Go-Back Land

Converted Land

The driver for this transition is a reestablishment of agricultural management. Depending on what the Go-Back Land looks like depends on the prescription. Proper grazing, brush management, herbicides, and/or fire are all potential practices the landowner can use to create more agricultural production on the site.

Transition T1A
State 1 to 2

Shrubs make up a portion of the plant community in the Grassland State, hence woody propagules are present. The Grassland State is not resistant to shrub dominance in the absence of fire. The mean fire return interval in the Grassland State is two to five years. Even with proper grazing and favorable climate conditions, lack of fire or brush control for 10 to 15 years will allow woody species to increase in canopy to reach the 35 percent threshold level. Improper grazing management, prolonged drought, and a warming climate will provide disturbance conditions which will accelerate this process. This transition can occur from any of the Grassland State Communities. The driver for Transition T1A is lack of fire and/or brush control. The Grassland State is always at risk for this transition because woody species are present in the grassland plant community. Introduction of aggressive woody invader species (i.e. juniper) increases the risk that this state transition will occur and accelerates the rate at which it is likely to occur.

Transition T1B
State 1 to 3

The transition to the Converted State from the Grassland State occurs when the prairie is plowed for planting to cropland or hayland. The threshold for this transition is the plowing of the prairie soil and removal of the prairie plant community. The Converted State includes cropland, tame pasture, and go-back land. The site is considered go-back land during the period between cessation of active cropping, fertilization, and weed control and the return to States 1 or 2. Agronomic practices are used to convert rangeland to the Converted State and to make changes between the communities in the Converted State. The driver for these transitions is management’s decision to farm the site.

Restoration pathway R2A
State 2 to 1

Restoration of the Shrubland State to the Grassland State requires substantial energy input. Mechanical or herbicidal brush control treatments can be used to remove woody species. A long-term prescribed fire program may sufficiently reduce brush density to a level below the threshold of the Grassland State, particularly if the woody component is dominated by species that are not re-sprouters following top removal. However, fire may not be sufficient to remove mature trees. A mixed program consisting of mechanical, chemical, and fire measures may be used. Brush control in combination with prescribed fire, proper grazing management, and favorable growing conditions may be the most economical means of creating and maintaining the desired plant community. Proper grazing management will be required to promote recovery of the understory towards a tallgrass community. If remnant populations of tallgrasses, midgrasses, and desirable forbs are not present at sufficient levels, range planting will be necessary to restore the grassland plant community. Depending on the understory community and inputs of seed, the restoration pathway can result in return to any of the Grassland State Communities. The driver for Restoration Pathway R2A is fire and/or brush control combined with restoration of the herbaceous community and proper grazing management. Restoration may require aggressive treatment of invader species.

Transition T2A
State 2 to 3

The transition to the Converted State from the Shrubland State (T2A) occurs when the prairie is plowed for planting to cropland or hayland. The size and density of brush in the Shrubland State will require heavy equipment and energy-intensive practices (e.g. rootplowing, raking, rollerchopping, or heavy disking) to prepare a seedbed. The threshold for this transition is the plowing of the prairie soil and removal of the prairie plant community. The Converted State includes cropland, tame pasture, and go-back land. The site is considered “go-back land” during the period between cessation of active cropping, fertilization, and weed control and the return to the “native” states. Agronomic practices are used to convert rangeland to the Converted State and to make changes between the communities in the Converted State. The driver for these transitions is management’s decision to farm the site.

Restoration pathway R3A
State 3 to 1

Restoration from the Converted State can occur in the short-term through active restoration or over the long-term due to cessation of agronomic practices. Cropland and tame pasture require repeated and continual inputs of fertilizer and weed control to maintain the Converted State. If the soil chemistry and structure have not been overly disturbed (which is most likely to occur with tame pasture) the site can be restored to the Grassland State. Heavily disturbed soils are more likely to return to the Shrubland State. Without continued disturbance from agriculture the site can eventually return to either the Grassland or Shrubland State. The level of disturbance while in the converted state determines whether the site restoration pathway is likely to be R3A (a return to the Grassland State) or T3A (a return to the Shrubland State). Return to native prairie communities in the Grassland State is more likely to be successful if soil chemistry and structure are not heavily disturbed. Preservation of favorable soil microbes increases the likelihood of a return to reference conditions. Converted sites can be returned to the Grassland State through active restoration, including seedbed preparation and seeding of native grass and forb species. Protocols and plant materials for restoring prairie communities are a developing part of restoration science. The driver for both of these restoration pathways is the cessation of agricultural disturbances.

Transition T3A
State 3 to 2

Transition to the Shrubland State (2) occurs with the cessation of agronomic practices. The site will move from the Abandoned Land Community when woody species begin to invade. After shrubs and trees have established over 35 percent, and reached a height greater than three feet, the threshold has been crossed. The driver for the change is lack of agronomic inputs, improper grazing, no brush management, and no fire.

Additional community tables

Table 11. Community 1.1 plant community composition

Group	Common name	Symbol	Scientific name	Annual production (lb/acre)	Foliar cover (%)
Grass/Grasslike
1	Tallgrasses			2000–3500
	big bluestem	ANGE	Andropogon gerardii	500–2750	–
	eastern gamagrass	TRDA3	Tripsacum dactyloides	500–2750	–
	switchgrass	PAVI2	Panicum virgatum	250–1750	–
	Indiangrass	SONU2	Sorghastrum nutans	250–1750	–
	little bluestem	SCSC	Schizachyrium scoparium	250–1600	–
	Florida paspalum	PAFL4	Paspalum floridanum	250–1100	–
2	Tall/Midgrasses			1200–2100
	sideoats grama	BOCU	Bouteloua curtipendula	200–1600	–
	silver beardgrass	BOLAT	Bothriochloa laguroides ssp. torreyana	100–1100	–
	Virginia wildrye	ELVI3	Elymus virginicus	100–1100	–
	plains lovegrass	ERIN	Eragrostis intermedia	50–800	–
	Texas cupgrass	ERSE5	Eriochloa sericea	50–800	–
	prairie Junegrass	KOMA	Koeleria macrantha	50–800	–
	Texas wintergrass	NALE3	Nassella leucotricha	100–800	–
	panicgrass	PANIC	Panicum	50–800	–
	vine mesquite	PAOB	Panicum obtusum	50–800	–
	marsh bristlegrass	SEPA10	Setaria parviflora	50–800	–
	Drummond's dropseed	SPCOD3	Sporobolus compositus var. drummondii	50–800	–
	Silveus' dropseed	SPSI2	Sporobolus silveanus	50–800	–
	white tridens	TRAL2	Tridens albescens	50–800	–
	longspike tridens	TRST2	Tridens strictus	50–800	–
	sedge	CAREX	Carex	50–800	–
	cylinder jointtail grass	COCY	Coelorachis cylindrica	50–800	–
	fall witchgrass	DICO6	Digitaria cognata	50–800	–
	purple threeawn	ARPU9	Aristida purpurea	50–800	–
Forb
3	Forbs			600–1050
	Maximilian sunflower	HEMA2	Helianthus maximiliani	0–900	–
	beardtongue	PENST	Penstemon	0–900	–
	blacksamson echinacea	ECAN2	Echinacea angustifolia	0–900	–
	Engelmann's daisy	ENPE4	Engelmannia peristenia	0–900	–
	button eryngo	ERYU	Eryngium yuccifolium	0–900	–
	prairie clover	DALEA	Dalea	0–750	–
	larkspur	DELPH	Delphinium	0–750	–
	bundleflower	DESMA	Desmanthus	0–750	–
	ticktrefoil	DESMO	Desmodium	0–750	–
	prairie acacia	ACANH	Acacia angustissima var. hirta	0–750	–
	yellow sundrops	CASE12	Calylophus serrulatus	0–750	–
	Indian paintbrush	CASTI2	Castilleja	0–750	–
	American star-thistle	CEAM2	Centaurea americana	0–750	–
	partridge pea	CHFA2	Chamaecrista fasciculata	0–750	–
	coastal indigo	INMI	Indigofera miniata	0–750	–
	dotted blazing star	LIPU	Liatris punctata	0–750	–
	sensitive plant	MIMOS	Mimosa	0–750	–
	yellow puff	NELU2	Neptunia lutea	0–750	–
	beeblossom	GAURA	Gaura	0–750	–
	vetch	VICIA	Vicia	0–750	–
	scurfpea	PSORA2	Psoralidium	0–750	–
	snoutbean	RHYNC2	Rhynchosia	0–750	–
	fuzzybean	STROP	Strophostyles	0–750	–
	vervain	VERBE	Verbena	0–500	–
	skullcap	SCUTE	Scutellaria	0–500	–
	prairie parsley	POLYT	Polytaenia	0–500	–
	Chalk Hill hymenopappus	HYTE2	Hymenopappus tenuifolius	0–500	–
	croton	CROTO	Croton	0–500	–
	ragweed	AMBRO	Ambrosia	0–500	–
	milkweed	ASCLE	Asclepias	0–500	–
	purple poppymallow	CAIN2	Callirhoe involucrata	0–500	–
	snow on the prairie	EUBI2	Euphorbia bicolor	0–500	–
Shrub/Vine
4	Shrubs and Trees			200–350
	live oak	QUVI	Quercus virginiana	0–350	–
	elm	ULMUS	Ulmus	0–300	–
	common hackberry	CEOC	Celtis occidentalis	0–300	–
	gum bully	SILA20	Sideroxylon lanuginosum	0–175	–
	coralberry	SYOR	Symphoricarpos orbiculatus	0–175	–

Interpretations

Animal community

The animal community in the Blackland differs depending on what state the site is currently in. Northern Bobwhite prefer the reference state. They require dense bunchgrasses for nesting and cover. As the site transitions into State 2, white-tailed deer will become more prevalent. Deer are woodland and edge species, with their primary diet consisting of browse. Mourning dove need open areas with semi-clear ground and forbs with desirable seed sources. Go-back land and communities with shortgrasses and forbs provide the best habitat for dove.

Hydrological functions

Rills and gullies are rare in the reference state. This site has potential for gullies to heal when in functioning condition. Drainage ways should be vegetated and stable. Water flow patterns are very short (less than two feet) if visible. Pedestals or terracettes do not occur in the reference community. Bare ground is essentially non-existent. Soils on this site are permeable when dry, infiltration is rapid, and runoff is slight. When soils are wet and have sealed over, soils are impermeable, infiltration is slow to very slow, and runoff is likely. Soils on this site have high shrink-swell values. This site has slowly permeable soils. Due to density of vegetation, even on sloping sites, small to medium-sized litter will move very little during intense storms. The soil surface under reference conditions is highly resistant to erosion; the soil stability class range is expected to be 6. This prairie site is dominated by tallgrasses and forbs having adequate litter and little bare ground which can provide for maximum infiltration and little runoff under normal rainfall events. The nearly level areas have a microrelief of knolls and depressions called gilgai. Sloping soils also have gilgai, which create microridges and valleys extending up and down the slopes. Soil erosion is very low if the tall grasses and the water trapping gilgai are present. Gilgai develops pools of standing water during wet weather. As much as six inches of water can be temporarily trapped in these gilgai microreliefs before runoff begins.

Recreational uses

Recreational uses include recreational hunting, hiking, camping, equestrian, and bird watching.

Wood products

Honey mesquite, eastern red cedar, and some oak are used for posts, firewood, charcoal, and other specialty wood products.

Other products

Jams and jellies are made from many fruit-bearing species, such as agarito. Seeds are harvested from many reference plants for commercial sale. Many grasses and forbs are harvested by the dried-plant industry for sale in dried flower arrangements. Honeybees are utilized to harvest honey from many flowering plants.

Supporting information

Inventory data references

These site descriptions were developed as part a Provisional Ecological Site project using historic soil survey manuscripts, available site descriptions, and low intensity field traverse sampling. Future work to validate the information is needed. This will include field activities to collect low, medium, and high-intensity sampling, soil correlations, and analysis of that data. A final field review, peer review, quality control, and quality assurance review of the will be needed to produce the final document.

Other references

1. Archer, S. 1994. Woody plant encroachment into southwestern grasslands and
savannas: rates, patterns and proximate causes. In: Ecological implications of livestock herbivory in the West, pp. 13-68. Edited by M. Vavra, W. Laycock, R. Pieper. Society for Range Management
Publication, Denver, CO.
2. Archer, S. and F.E. Smeins. 1991. Ecosystem-level Processes. Chapter 5 in: Grazing Management: An Ecological Perspective. Edited by R.K. Heitschmidt and J.W. Stuth. Timber Press, Portland, OR.
3. Bestelmeyer, B.T., J.R. Brown, K.M. Havstad, R. Alexander, G. Chavez, and J.E. Herrick. 2003. Development and use of state-and-transition models for rangelands. J. Range Manage. 56(2): 114-126.
4. Brown, J.R. and S. Archer. 1999. Shrub invasion of grassland: recruitment is continuous and not regulated by herbaceous biomass or density. Ecology 80(7): 2385- 2396.
5. Foster, J.H. 1917. Pre-settlement fire frequency regions of the United States: a first approximation. Tall Timbers Fire Ecology Conference Proceedings No. 20.
6. Gould, F.W. 1975. The Grasses of Texas. Texas A&M University Press, College Station, TX. 653p.
7. Hamilton, W. and D. Ueckert. 2005. Rangeland Woody Plant Control: Past, Present, and Future. Chapter 1 in: Brush Management: Past, Present, and Future. pp. 3-16. Texas A&M University Press.
8. Scifres, C.J. and W.T. Hamilton. 1993. Prescribed Burning for Brush Management: The South Texas
Example. Texas A&M University Press, College Station, TX. 245 p.
9. Smeins, F., S. Fuhlendorf, and C. Taylor, Jr. 1997. Environmental and Land Use Changes: A Long Term Perspective. Chapter 1 in: Juniper Symposium 1997, pp. 1-21. Texas Agricultural Experiment Station.
10. Stringham, T.K., W.C. Krueger, and P.L. Shaver. 2001. State and transition modeling: and ecological process approach. J. Range Manage. 56(2):106-113.
11. Texas Agriculture Experiment Station. 2007. Benny Simpson’s Texas Native Trees
(http://aggie-horticulture.tamu.edu/ornamentals/natives/).
12. Texas A&M Research and Extension Center. 2000. Native Plants of South Texas
(http://uvalde.tamu.edu/herbarium/index.html).
13. Thurow, T.L. 1991. Hydrology and Erosion. Chapter 6 in: Grazing Management: An Ecological Perspective. Edited by R.K. Heitschmidt and J.W. Stuth. Timber Press, Portland, OR.
14. USDA/NRCS Soil Survey Manuals counties within MLRA 86A.
15. USDA, NRCS. 1997. National Range and Pasture Handbook.
16. USDA, NRCS. 2007. The PLANTS Database (http://plants.usda.gov). National Plant Data Center, Baton Rouge, LA 70874-4490 USA.
17. Vines, R.A. 1984. Trees of Central Texas. University of Texas Press, Austin, TX.
18. Wright, H.A. and A.W. Bailey. 1982.

Contributors

Lem Creswell
Mark Moseley
Tyson Hart

Approval

Bryan Christensen, 9/21/2023

Acknowledgments

Special thanks to the following personnel for assistance and/or guidance with development of this ESD: Justin Clary, NRCS, Temple, TX; Mark Moseley, NRCS, San Antonio, TX; Monica Purviance, NRCS, Greenville, TX; Jim Eidson, The Nature Conservancy, Celeste, TX; and Gary Price (Rancher) and the 77 Ranch, Blooming Grove, TX.

Reviewers:
Lem Creswell, RMS, NRCS, Weatherford, Texas
Jeff Goodwin, RMS, NRCS, Corsicana, Texas

Rangeland health reference sheet

Interpreting Indicators of Rangeland Health is a qualitative assessment protocol used to determine ecosystem condition based on benchmark characteristics described in the Reference Sheet. A suite of 17 (or more) indicators are typically considered in an assessment. The ecological site(s) representative of an assessment location must be known prior to applying the protocol and must be verified based on soils and climate. Current plant community cannot be used to identify the ecological site.

Author(s)/participant(s)	Lem Creswell, RMS, NRCS, Weatherford, Texas
Contact for lead author	817-596-2865
Date	05/01/2008
Approved by	Bryan Christensen
Approval date
Composition (Indicators 10 and 12) based on	Annual Production