Natural Resources
Conservation Service
Ecological site R081BY354TX
Very Shallow
23-31 PZ
Last updated: 9/19/2023
Accessed: 08/26/2026
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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): 081B–Edwards Plateau, Central Part
This area is entirely in south-central Texas. It makes up about 11,125 square miles (28,825 square kilometers). The towns of Fredericksburg, Junction, Menard, Rocksprings, and Sonora are in this MLRA. Interstate 10 crosses the middle part of the area. A few State parks and State historic sites are in this MLRA.
Classification relationships
USDA-Natural Resources Conservation Service, 2006.
-Major Land Resource Area (MLRA) 81BEcological site concept
The Very Shallow ecological site is located on uplands with soils less than 10 inches deep over a petrocalcic horizon or bedrock.
Associated sites
R081BY326TX Clay Loam 23-31 PZ
The Clay Loam may be encountered down slope.
R081BY324TX Clay Flat 23-31 PZ
The Clay Flat may be encountered on adjacent slopes.
Similar sites
R081BY343TX Shallow 23-31 PZ
The Shallow site is similar in that both sites are located on similar topography and parent material.
Table 1. Dominant plant species
Tree Not specified
Shrub Not specified
Herbaceous (1) Bouteloua curtipendula
(2) Schizachyrium scopariumPhysiographic features
Sites are on nearly level to steep sloping uplands. They are formed in calcareous loamy alluvium derived from limestone. This site is usually found on stream terraces, alluvial fans, hills, ridges, divides, and foot slopes. The elevation ranges from 1,000 feet to 2,500 feet above sea level. Slope ranges from 1 to 40 percent. The majority of the site is used for rangeland. Runoff is low to very high depending on slope and vegetative cover.
Table 2. Representative physiographic features
Landforms (1) Plateau > Ridge
(2) Plateau > Plain
(3) Plateau > Stream terrace
Runoff class Low to very high Flooding frequency None Ponding frequency None Elevation 1000 – 2500 ft Slope 1 – 40 % Aspect Aspect is not a significant factor Climatic features
The climate in the MLRA 81B is subtropical subhumid on the eastern portion and subtropical steppe on the western portion of the MLRA. Winters are dry, and the summers are hot and humid. The precipitation increases from west to east and the temperatures increase from north to south. The area usually receives 65 to 70 percent sunshine each year. The majority of the rainfall occurs during the warm months of April to October. Most precipitation comes from thunderstorms that vary in the amount of water received and the areas covered. Spring is characterized by fluctuating patterns, but mild temperatures prevail. July and August are relatively dry and hot with little weather variability day-to-day. As summer progresses through fall, an increase of precipitation usually occurs in the eastern portions while a decrease of precipitation occurs to the west. Winter temperatures are mild, but polar Canadian air masses bring rapid drops in temperature. These cold spells last 2 or 3 days. Prevailing winds are southerly with March and April the windiest months.
Table 3 Representative climatic features
Frost-free period (characteristic range) 210-240 days Freeze-free period (characteristic range) 240-280 days Precipitation total (characteristic range) 30-30 in Frost-free period (actual range) 210-240 days Freeze-free period (actual range) 240-280 days Precipitation total (actual range) 20-30 in Frost-free period (average) 230 days Freeze-free period (average) 260 days Precipitation total (average) 30 in Characteristic rangeActual rangeBarLineFigure 2. Monthly precipitation range
Characteristic rangeActual rangeBarLineFigure 3. Monthly minimum temperature range
Characteristic rangeActual rangeBarLineFigure 4. Monthly maximum temperature range
BarLineFigure 5. Monthly average minimum and maximum temperature
Figure 6. Annual precipitation pattern
Figure 7 Annual average temperature pattern
Climate stations used
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(1) BRADY [USC00411017], Brady, TX
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(2) FREDERICKSBURG [USC00413329], Fredericksburg, TX
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(3) FT MCKAVETT [USC00413257], Fort Mc Kavett, TX
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(4) HUNT 10 W [USC00414375], Hunt, TX
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(5) JUNCTION 4SSW [USC00414670], Junction, TX
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(6) JUNCTION KIMBLE CO AP [USW00013973], Junction, TX
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(7) MENARD [USC00415822], Menard, TX
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(8) ROCKSPRINGS 1S [USC00417706], Rocksprings, TX
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(9) SAN SABA [USC00417992], San Saba, TX
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(10) EDEN [USC00412741], Eden, TX
">Influencing water features
There are no wetlands or stream features on this site.
Wetland description
N/A
Soil features
The soils are well drained and permeability is moderately slow to moderately rapid. The parent material is loamy alluvium or residuum derived from limestone. The surface layer is dark grayish-brown, calcareous loam about 6 to 9 inches thick. Depth to the petrocalcic horizon or bedrock is generally less than 10 inches. Cemented caliche fragments occur throughout the soil profile. Gravel and/or cobble occupy up 40 percent on the surface and as much as 50 percent in the subsoil. The available water capacity is low the soil profile can contain as much as 95 percent calcium carbonate. Soil series correlated to this site include: Cho, Eckert, Eola, Mailtrail, and Yates.
Table 4. Representative soil features
Parent material (1) Residuum – limestone
(2) Alluvium – limestone and sandstone
Surface texture (1) Very cobbly loam
(2) Very gravelly clay loam
(3) Very flaggy fine sandy loam
Family particle size (1) Loamy
(2) Loamy-skeletal
Drainage class Well drained Permeability class Moderately slow to moderately rapid Depth to restrictive layer 4 – 10 in Soil depth 4 – 10 in Surface fragment cover <=3" 2 – 30 % Surface fragment cover >3" 5 – 40 % Available water capacity
(0-10in)0.3 – 1.8 in Calcium carbonate equivalent
(0-10in)40 – 95 % Electrical conductivity
(0-10in)0 – 2 mmhos/cm Sodium adsorption ratio
(0-10in)Not specified Soil reaction (1:1 water)
(0-10in)7.4 – 8.4 Subsurface fragment volume <=3"
(4-10in)0 – 35 % Subsurface fragment volume >3"
(4-10in)0 – 40 % Ecological dynamics
The Very Shallow Ecological Site is a midgrass dominated prairie with widely scattered trees and understory shrubs. Historically, the site evolved under the influences of grazing and browsing by endemic pronghorn antelope, deer, and migratory bison, severe droughts, and frequent fires. Fires are estimated to have occurred at 7 to 12 year-intervals maintaining brushy and woody species at about five percent canopy. The frequent fires and droughts were postulated to be the major influences on developing the plant communities.
Midgrasses such as sideoats grama (Bouteloua curtipendula), little bluestem (Schizachyrium scoparium), feathery bluestems (Bothriochloa spp.), and green sprangletop (Leptochloa dubia) dominated the vegetation in the early 1800’s. Buffalograss (Bouteloua dactyloides) and curlymesquite (Hilaria belangeri) were characteristic shortgrasses. Frequent fires favored grasses over woody plants and forbs, but there were a wide variety of forbs present. Trees, primarily live oak (Quercus virginiana), occupied deeper soil pockets underlain by marl on areas protected from wildfires, shading less than three percent of the site. Because of the effects of infrequent fires, some of the fire resistant woody species existed as shrubs giving the site a shrubby or “shinnery” appearance. Shrubs provided only two to four percent woody plant canopy.
The Midgrass Prairie Community (1.1) was relatively stable and resilient within the climate, soil, grazing, and fire regime until settlement and the advent of fencing and animal husbandry in the late 1800’s. Not understanding the limits of rangeland productivity, European settlers overstocked livestock almost universally. As overgrazing by livestock and wildlife occurred, there was a reduction of palatable plants, a decline in plant cover, mulch, soil organic matter, and a reduction in intensity and frequency of fires. The shift in plant cover and decline in soil properties favored woody plant encroachment. The woody and herbaceous increasers were generally endemic species released from the effects of fire or from competition. The resulting plant community was a Midgrass Savannah Community (1.2). In this transitional phase, the more palatable midgrasses transition to less palatable, or more grazing resistant, shortgrasses and midgrasses like feathery bluestems, vine mesquite (Panicum obtusum), and curlymesquite. The grassland component still dominated the annual primary production, but the proportion of encroaching woody species, mainly shrubs, was increasing.
When the Midgrass Savannah Community is continually overgrazed and fire is excluded, the process of ecological succession proceeds toward woody plant dominance. The more palatable midgrasses and forbs are replaced by more grazing resistant shortgrasses and less palatable forbs. As grass cover declines, litter, mulch, and soil organic matter decrease and bare ground, erosion, and other desertification processes increase. This is a very fragile site in that small soil losses have a significant impact and the loss is essentially irreversible. The microclimate in the grassland areas becomes more arid. The site becomes favorable to the invasion of species previously repressed by fire or herbaceous competition. Mesquite (Prosopis glandulosa), Ashe juniper (Juniperus ashei), and pricklypear (Opuntia spp.) are early increasers. Redberry juniper (Juniperus pinchotii) often invades the area from the west and north. When the woody plant community exceeds 15 percent canopy and/or the woody invaders become dense enough and large enough to resist fire (about five feet in height), rest from grazing pressure will generally not restore the grassland community. When this plant composition and structure is reached, not enough fine fuel exists for fires to effectively control woody species and forbs. As this threshold is crossed, the plant community transitions into the Mixed-Brush/Shortgrass Community (2.1). This threshold also marks the beginning of the Shrubland State. Until this threshold is breached, the change from grassland to shrubland can be reversed, or halted, with proper grazing management and appropriate prescribed burning practices. Individual plant treatments can also be effective to remove the unwanted woody plants before they become too dense to treat individually.
With continued overgrazing, mesquite and/or juniper continue to increase, and other shrubs begin forming thickets. Buffalograss, curly mesquite, three-awns (Aristida spp.) and broomweed (Gutierrezia spp.) are representative shortgrasses and forbs found in this community. In time, the less palatable or more grazing resistant shortgrasses and forbs will replace the more palatable shortgrasses. Cool-season grasses such as Texas wintergrass (Nassella leucotricha) and annual bromes (Bromus spp.) also increase in the protection and shading of shrubs.
In the Mixed-Brush/Shortgrass Community (2.1), the process of retrogression can be reversed with moderately intensive brush control and good grazing management that allows the application of prescribed burning. If these conservation practices are not applied, the woody canopy will continue to increase in dominance and ground cover, even without livestock grazing or deer browsing. Once brush cover exceeds 25 to 30 percent, understory herbage production is very limited and generally composed of unpalatable shrubs, grasses, and forbs in the woody interspaces. The resultant woody plant dominated community is the Mixed-Brush/Shrubland Community (2.2). Mesquite and/or juniper dominate the overstory, although occasionally oaks are present. Brushy species such as agarito (Mahonia trifoliata), wolfberry (Lycium spp.), and javelinabush (Condalia ericoides) often form thickets. The remaining shortgrasses, cool-season grasses, and forbs are in weakened condition. Primary production is from low-quality trees, shrubs, forbs, and grasses.
The microclimate becomes drier as interception losses increase with brush canopy cover and more runoff occurs during rainfall. Litter amounts are greatly reduced exposing bare soil. The exposed soil crusts readily, creating opportunities for rill erosion to occur. Considerable litter and soil movement occur during heavy rainfall events. Until maximum ground cover by woody species is approached, desertification and erosion continue in the interspaces. Once shrub canopy cover is maximized, however, the hydrologic processes, energy flow, and nutrient cycling stabilize under the woodland/shrubland environment. This process may take many years to become stable.
Major expense and energy are required to restore the Mixed-Brush/Shrubland Community (2.2) back to a productive grassland community. Generally, expensive mechanical or herbicidal treatments (IPT) range planting, grazing deferment, and prescribed burning are required for restoration. Erosion and fertility losses during the retrogression process may preclude the plant community’s ability to be restored. Very little of the Very Shallow site has been plowed because the lack of soil depth is not well suited for cultivation. The site is highly erodible when exposed by overgrazing, cultivation, or crop production. There are, however, some areas of the site planted to pasture grasses, small grains, or wildlife food plots. Many of these are inclusions with adjacent Shallow or Clay Loam sites. Generally, most fields in the Very Shallow Site previously cultivated for crops have been returned to native grasses and managed as rangeland.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 textEcosystem states
T1A - Absence of disturbance and natural regeneration over time, may be coupled with excessive grazing pressure R2A - Reintroduction of historic disturbance return intervals State 1 submodel, plant communities
State 2 submodel, plant communities
State 1
GrasslandDominant plant species
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sideoats grama (Bouteloua curtipendula), grass
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little bluestem (Schizachyrium scoparium), grass
Community 1.1
Midgrass Prairie
Figure 8. Midgrass Prairie Community
The reference plant community is a fire-maintained prairie of midgrasses. Woody plants, mostly shrubs, provided little canopy cover. Live oak, netleaf hackberry (Celtis laevigata var. reticulata), Texas mulberry (Morus microphylla,) and shrubs are widely scattered in protected areas and along draws. Catclaw acacia (Acacia greggii), sumacs (Rhus spp.), Texas kidneywood (Eysenhardtia texana), elbowbush (Forestiera pubescens), ephedra (Ephedra spp.), and javelinabush are typical shrubs. Little bluestem occupies favorable microsites and is locally abundant. Sideoats grama is the dominant midgrass throughout the site, but Texas cupgrass, green sprangletop, vine mesquite, meadow dropseed (Sporobolus asper var. asper), feathery bluestems, Canada wildrye (Elymus canadensis), and Texas wintergrass (Nassella leucotricha), are also abundant. Shortgrasses included blue grama (Bouteloua gracilis), curlymesquite, buffalograss, tridens (Tridens spp.), and bristlegrass (Setaria spp.). Characteristic forbs are dotted gayfeather (Liatris punctata), trailing ratany (Krameria lanceolata), awnless bushsunflower (Simsia calva), Engelmann’s daisy (Engelmannia peristenia), wooly-white (Hymenopappus spp.), half-shrub sundrop (Calylophus serrulatus), catclaw sensitivebriar (Mimosa aculeaticarpa var. biuncifera), and bundleflower (Desmanthus spp.). Live oak, hackberry (Celtis spp.) and mesquite are widely scattered tree species.
Productivity is limited by the very shallow soils having restrictive layers of caliche and limestone, course surface fragments, and very low water availability. In reference condition, the site produces from 800 to 2,500 pounds per acre annually, depending upon the particular soil series and amount of precipitation. Annual forbs add to the annual production in favorable moisture years. Grasses make up 85 to 90 percent of the annual production. The abundant grass cover and considerable accumulated mulch aide in the infiltration of rainfall and reduces runoff in all but heavy rains. The Midgrass Prairie Community furnishes good habitat for grazing livestock and wildlife. With continued overgrazing, a decrease in intensity and frequency of fires, and no brush management, this plant community transitions very quickly into the Midgrass Savannah Community (1.2).Figure 9. Annual production by plant type (representative values) or group (midpoint values)
Table 5. Annual production by plant type
Plant type Low
(lb/acre)Representative value
(lb/acre)High
(lb/acre)Grass/Grasslike 680 1700 2125 Forb 56 140 175 Shrub/Vine 40 100 125 Tree 24 60 75 Total 800 2000 2500 Figure 10. Plant community growth curve (percent production by month). TX3614 , Midgrass & Shortgrass Savannah Community. Warm-season rangeland with peaks in production from April, May and June and in September and October..
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec J F M A M J J A S O N D 2 3 5 13 23 15 4 5 15 7 5 3 Community 1.2
Midgrass Savannah
Figure 11. Midgrass Savannah Community
The Midgrass Savannah Community is a grassland being invaded by indigenous or woody species that had been held at low densities by repeated fires or competition from a vigorous grass component. Numerous brushy species, plus juniper and mesquite, are increasing in density because overgrazing by livestock has reduced grass cover, increased soil exposure, and reduced fine fuel for fire. In this phase, the increasing woody species are generally less than three feet tall and still subject to control by fire and improved grazing management. The woody canopy varies between 10 and 15 percent depending on the severity of grazing, time since last burned, and availability of invading species.
Typically, mesquite and/or juniper, sumacs (Sumac spp.), agarito, javelinabush, condalia and feather dalea (Dalea spp.) have increased in density and size. The prairie is converting into a savannah by encroaching woody species. Most of the reference grasses are present, although in lesser amounts. Important grasses for this community are sideoats grama, little bluestem, feathery bluestems, tall dropseed, (Sporobolus compositus var. drummondii), meadow dropseed, vine mesquite, plains lovegrass (Eragrostis intermedia), Texas wintergrass, and Canada wildrye. White tridens (Tridens albescens), buffalograss, and curlymesquite are representative shortgrasses. All but the least grazing resistant perennial forbs persist.
Annual primary production ranges from 700 to 2,300 pounds, depending on precipitation and the soil series. Forage production is still predominantly grass. Grazing has reduced plant cover, litter, and mulch and has increased bare ground slightly exposing the soil to some erosion. There could be some mulch and litter movement during rainstorms but on gentle slopes, little soil movement will take place in this vegetation phase. The changes in composition are small initially, but unless proper grazing and prescribed burning are initiated, the woody species continue to increase in size and density. When the canopy of the woody plants becomes dense enough (15 to 20 percent) and tall enough (more than five feet) to suppress grass growth and resist fire damage, a threshold is reached. The Midgrass Savannah Community transitions into the Mixed-Brush/Shortgrass Community (2.1).Pathway 1.1A
Community 1.1 to 1.2
Midgrass Prairie
Midgrass SavannahOvergrazing, lack of fire, and allowing woody species to proliferate will shift the reference community into a Shortgrass Savannah Community (1.2).
Pathway 1.2A
Community 1.2 to 1.1
Midgrass Savannah
Midgrass PrairiePrescribed grazing, return of fire, and brush management can return the Shortgrass Savannah Community (1.2) to reference conditions.
State 2
ShrublandDominant plant species
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mesquite (Prosopis), shrub
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Ashe's juniper (Juniperus ashei), shrub
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Pinchot's juniper (Juniperus pinchotii), shrub
Community 2.1
Mixed-brush/Shortgrass
Figure 12. Mixed-brush/Shortgrass Community
The Mixed-Brush/Shortgrass Community (2.1) is a shrub invaded grassland with 15 to 30 percent woody plant canopy of mixed-brush. Brush density has increased and shortgrasses have largely replaced midgrasses. This plant community is the result of selective overgrazing and browsing resulting in a differential response of plants to defoliation. With continued overgrazing, the diversity of the grassland species declines, while woody species and unpalatable forbs increase. All but the most palatable woody species increase in density and size. Mesquite and Ashe juniper are common increasers throughout the MLRA, while redberry juniper (Juniperus pinchotii) is found in the western section. Many of the reference shrubs are present. Javelinabush, agarito, prickly ash (Zanthoxylum spp.), condalia (Condalia spp.), shin oak (Quercus sinuata), and sumac often form thickets.
Remnants of reference grasses, forbs, and unpalatable invaders occupy the interspaces between trees and shrubs. Cool-season grasses such as Texas wintergrass, plus other grazing-resistant species, can be found under and around woody plants where they find protection from grazing. Because of pressure and competition for nutrients and water, the grassland component shows lack of vigor and productivity. Characteristic herbaceous species are buffalograss, curlymesquite, three-awns (Aristida spp.), hairy tridens (Erioneuron pilosum), hairy grama (Bouteloua hirsuta), and sedges (Carex spp.), although remnants of the reference midgrasses remain. Representative forbs include dalea (Dalea spp.), gray goldaster (Heterotheca canescens), croton (Croton spp.), verbena (Verbena spp.), Queen’s delight (Stillingia sylvatica), prairie coneflower (Ratibida columnifera), and Western ragweed.
As the grassland vegetation declines, more soil is exposed to crusting and erosion. During this phase, sheet and rill erosion can be high, especially on steeper slopes. Higher interception losses by the increasing woody canopy combined with evaporation and runoff can reduce the effectiveness of rainfall. Primary plant production has decreased due to decline in soil structure and organic matter. Annual primary production is approximately 500 to 2,000 pounds and is balanced between woody and herbaceous species. Browsing animals, such as goats and deer, find fair food value if browsing by sheep or deer has not been excessive, but forage quality for cattle is low. Good grazing management alone cannot reverse the succession towards dense shrubland. Unless brush management practices are applied at this stage, the transition will continue. The trend can be reversed with intensive brush management such as individual plant treatments combined with prescribed grazing and burning.Community 2.2
Mixed-brush/Shrubland
Figure 13. Mixed-brush/Shrubland Community
Live oak, juniper and/or mesquite dominate the Mixed-Brush/Shrubland Community (2.2). Common shrubs are pricklypear, agarita, sumacs, condalia, elbowbush, prickly ash (Zanthoxylum spp.), and tasajillo (Cylindropuntia leptocaulis). Brush cover is greater than 30 percent and can exceed 50 percent ground cover. Only remnants of reference grasses, forbs, and unpalatable invaders occupy the interspaces. Characteristic grasses found in this plant community are Texas wintergrass, sedges (Carex spp.), tumble windmillgrass (Chloris verticellata), Hall’s panicum (Panicum hallii var. hallii), rough tridens (Tridens muticus var. muticus), slim tridens (Tridens muticus), fall witchgrass (Digitaria cognata), Texas grama (Bouteloua rigidiseta var. rigidiseta), and red grama (Bouteloua trifida). Characteristic forbs include dotted gayfeather (Liatris punctata var. punctata), orange zexmenia (Wedelia hispida), croton (Croton spp.), Western ragweed (Ambrosia psilostachya), prairie coneflower (Ratibida columnifera), gray goldaster, and broomweed (Gutierrezia spp.).
The shrub canopy acts to intercept rainfall and increase evapotranspiration losses, creating a more xeric microclimate. Soil organic matter and mulch are reduced, exposing more soil surface. The exposed soil crusts readily and becomes susceptible to wind and water erosion. Rill erosion, terracettes, and pedestaling are common under extreme conditions. Unless brush control and proper stocking are applied, the brush community will continue to thicken until it stabilizes with the climate and soil. Good cover for wildlife can still be found, but only limited preferred forage and browse are available for livestock or wildlife. Alternatives for restoration include brush control and range planting to return vegetation back to the desired plant community and then prescribed grazing and prescribed burning to maintain the desired plant community. Without major management inputs, this state cannot be reversed.Pathway 2.1A
Community 2.1 to 2.2
Mixed-brush/Shortgrass
Mixed-brush/ShrublandContinued heavy grazing, lack of fire, and absence of brush management will transition the site into a Mixed-brush/Shrubland Community.
Transition T1A
State 1 to 2Heavy abusive grazing, absence of fire, and lack of brush management transition this site to a Shrubland State (2).
Restoration pathway R2A
State 2 to 1Prescribed grazing, prescribed burning, brush management, and possibly range planting are required to restore the Shrubland State (2) back to the reference state. Depending on previous land history, erosion and soil fertility may be so low that a full restoration is unattainable.
Additional community tables
Table 6. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Grass/Grasslike1 tallgrass 80–250 little bluestem SCSC Schizachyrium scoparium 80–250 – 2 midgrasses 240–750 sideoats grama BOCU Bouteloua curtipendula 240–750 – blue grama BOGR2 Bouteloua gracilis 240–750 – beardgrass BOTHR Bothriochloa 240–750 – green sprangletop LEDU Leptochloa dubia 240–750 – 3 midgrasses 200–625 plains lovegrass ERIN Eragrostis intermedia 200–625 – bush muhly MUPO2 Muhlenbergia porteri 200–625 – vine mesquite PAOB Panicum obtusum 200–625 – Reverchon's bristlegrass SERE3 Setaria reverchonii 200–625 – plains bristlegrass SEVU2 Setaria vulpiseta 200–625 – composite dropseed SPCOC2 Sporobolus compositus var. compositus 200–625 – Drummond's dropseed SPCOD3 Sporobolus compositus var. drummondii 200–625 – white tridens TRAL2 Tridens albescens 200–625 – 4 shortgrasses 80–250 buffalograss BODA2 Bouteloua dactyloides 80–250 – curly-mesquite HIBE Hilaria belangeri 80–250 – 5 shortgrasses 40–125 threeawn ARIST Aristida 40–125 – hairy grama BOHI2 Bouteloua hirsuta 40–125 – Texas grama BORI Bouteloua rigidiseta 40–125 – red grama BOTR2 Bouteloua trifida 40–125 – fall witchgrass DICO6 Digitaria cognata 40–125 – Scribner's rosette grass DIOLS Dichanthelium oligosanthes var. scribnerianum 40–125 – hairy woollygrass ERPI5 Erioneuron pilosum 40–125 – sand dropseed SPCR Sporobolus cryptandrus 40–125 – slim tridens TRMU Tridens muticus 40–125 – slim tridens TRMUE Tridens muticus var. elongatus 40–125 – 6 cool-season grasses 40–125 sedge CAREX Carex 40–125 – Canada wildrye ELCA4 Elymus canadensis 40–125 – Texas wintergrass NALE3 Nassella leucotricha 40–125 – Forb7 forbs 56–175 Indian mallow ABUTI Abutilon 56–175 – onion ALLIU Allium 56–175 – Cuman ragweed AMPS Ambrosia psilostachya 56–175 – white sagebrush ARLU Artemisia ludoviciana 56–175 – aster ASTER Aster 56–175 – milkvetch ASTRA Astragalus 56–175 – Drummond's clematis CLDR Clematis drummondii 56–175 – croton CROTO Croton 56–175 – prairie clover DALEA Dalea 56–175 – purple prairie clover DAPU5 Dalea purpurea 56–175 – bundleflower DESMA Desmanthus 56–175 – blacksamson echinacea ECAN2 Echinacea angustifolia 56–175 – Engelmann's daisy ENPE4 Engelmannia peristenia 56–175 – beeblossom GAURA Gaura 56–175 – false goldenaster HETER8 Heterotheca 56–175 – trailing krameria KRLA Krameria lanceolata 56–175 – dotted blazing star LIPU Liatris punctata 56–175 – menodora MENOD Menodora 56–175 – catclaw mimosa MIACB Mimosa aculeaticarpa var. biuncifera 56–175 – Texas sacahuista NOTE Nolina texana 56–175 – Texas sage SATE3 Salvia texana 56–175 – awnless bushsunflower SICA7 Simsia calva 56–175 – globemallow SPHAE Sphaeralcea 56–175 – queen's-delight STSY Stillingia sylvatica 56–175 – vervain VERBE Verbena 56–175 – creepingoxeye WEDEL Wedelia 56–175 – Shrub/Vine8 shrubs/vines 40–125 acacia ACACI Acacia 40–125 – catclaw acacia ACGR Acacia greggii 40–125 – snakewood CONDA Condalia 40–125 – featherplume DAFO Dalea formosa 40–125 – jointfir EPHED Ephedra 40–125 – Texas kidneywood EYTE Eysenhardtia texana 40–125 – stretchberry FOPU2 Forestiera pubescens 40–125 – snakeweed GUTIE Gutierrezia 40–125 – desert-thorn LYCIU Lycium 40–125 – algerita MATR3 Mahonia trifoliolata 40–125 – pricklypear OPUNT Opuntia 40–125 – fragrant sumac RHAR4 Rhus aromatica 40–125 – littleleaf sumac RHMI3 Rhus microphylla 40–125 – evergreen sumac RHVIV Rhus virens var. virens 40–125 – greenbrier SMILA2 Smilax 40–125 – yucca YUCCA Yucca 40–125 – Tree9 trees 24–75 eastern redbud CECA4 Cercis canadensis 24–75 – netleaf hackberry CELAR Celtis laevigata var. reticulata 24–75 – juniper JUNIP Juniperus 24–75 – littleleaf leadtree LERE5 Leucaena retusa 24–75 – Texas mulberry MOMI Morus microphylla 24–75 – mesquite PROSO Prosopis 24–75 – oak QUERC Quercus 24–75 – Table 7. Community 1.2 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 8. Community 2.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 9. Community 2.2 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Interpretations
Animal community
This site is used to produce domestic livestock and to provide habitat for native wildlife. Cow-calf operations are the primary livestock enterprise, although stocker cattle are also grazed. Sheep, Angora goats, and Spanish goats were formerly raised in large numbers. Sheep are still present in reduced numbers, while meat goats are now present in fairly high numbers. Boer goats have been introduced, either purebred or crossed with Spanish goats, to obtain a larger meat animal. Reports indicate that Boers do not browse as heavily as earlier breeds.
Sustainable stocking rates have declined drastically over the past 100 years due to the deterioration of the reference plant community. An assessment of vegetation is needed to determine the site’s current carrying capacity. Calculations used to determine livestock stocking rate should be based on forage production remaining after determining use by resident wildlife, then refined by frequent careful observation of the plant community’s response to animal foraging.
A large diversity of wildlife is native to this site. In the reference plant community, migrating bison, grazing primarily during wetter periods, pronghorn, white-tailed deer and turkey were the more predominant herbivore species. With the subsequent transformation of the plant community, due primarily to the influence of man and climate change, the kind and proportion of wildlife species have been altered.
Except for a few domestic herds, bison have been eliminated. With the eradication of the screwworm fly, increase in woody vegetation and man-suppressed natural predation, deer numbers have increased and are often in excess of carrying capacity. Where deer numbers are excessive, overbrowsing and overuse of preferred forbs causes deterioration of the plant community. Progressive management of deer populations through hunting can keep populations in balance and provide an economically important ranching enterprise. Achieving a balance between brushy cover and more open plant communities on this and adjacent sites is important to deer management. Competition among deer, sheep, and goats must be a consideration in livestock and wildlife management to prevent damage to the plant community.
Various species of exotic wildlife have been introduced on the site, including deer such as axis, sika, fallow, and red; antelope such as sable, oryx, blackbuck, and nilgai, and sheep such as barbados (mouflon) and aoudad with various degrees of success. Their numbers must be included along with livestock and native wildlife, primarily white-tailed deer, in any management plan. Feral hogs may feed on the site. They can be damaging to the plant community if their numbers are not managed. Smaller mammals include many kinds of rodents, jackrabbit, cottontail, raccoon, ringtail, skunk, and armadillo. Mammalian predators include coyote, red fox, gray fox, bobcat, and mountain lion. Wolves were common in earlier times, bears resided in some areas, and an occasional jaguar or ocelot was encountered. Many species of snakes and lizards are native to the site.
Many species of birds are found on this site including game birds, songbirds, and birds of prey. Major game birds that are economically important are turkey, bobwhite quail, scaled (blue) quail, and mourning dove. Turkeys prefer plant communities with substantial amounts of shrubs and trees interspersed with grassland. Quail prefer a combination of low shrubs, bunch grass (critical for nesting cover), bare ground, and low successional forbs. The different species of songbirds vary in their habitat preferences. Habitat on this site that provides a large diversity of grasses, forbs, and shrubs will support a good variety and abundance of songbirds. Birds of prey are important to keep the numbers of rodents, rabbits, and snakes in balance. Different species of raptors benefit from a diverse plant community as well.Hydrological functions
The site is a well-drained, very shallow upland with nearly level to gentle slopes. Most soils are 6 to 9 inches deep with pockets of deeper soils included. The shallowness to a hard limestone or caliche layer limits water holding capacity. Runoff is slow due to gentle slopes if there is a good vegetative cover. Exposed soil crusts readily which allow the soil to become more susceptible to runoff and erosion. Under reference conditions, grassland vegetation intercepts and utilizes much of the incoming rainfall. Only during extended rains or heavy thunderstorms does runoff occur. Litter and soil movement is slight.
Standing plant cover, duff and organic matter decrease and surface runoff increases as the Midgrass Prairie Community (1.1) transitions to the Midgrass Savannah Community (1.2). These processes continue as the site transitions to the Mixed-Brush/Shortgrass Community (2.1), and finally the Mixed-Brush/Shrubland Community (2.2). As canopy surpasses 40 to 50 percent, the hydrological and ecological processes, nutrient cycling, and energy flow stabilize within the woody plant canopy. Evaporation and interception losses are higher, however, resulting in less moisture reaching the soil. If overgrazing continues, the plant community deteriorates further, and desertification processes continue. Decreased mulch and more bare ground allow erosion from soils in openings between trees until a mature shrubland state is reached.Recreational uses
The Very Shallow site occurs in association with Limestone Hill and Clay Loam sites. Together these sites are well suited for many outdoor recreational uses including recreational hunting, hiking, camping, equestrian, and bird watching. The area provides diverse scenic beauty and many opportunities for recreation and hunting.
Wood products
Specialty wood products are made from juniper, mesquite, oak, and many shrubs. Mesquite, juniper, and oak are used for posts and firewood.
Other products
Jams and jellies are made from many fruit-bearing species. Seeds are harvested from many plants for commercial sale. Grasses and forbs may be harvested by the dried-plant industry for sale in dried flower arrangements. Honeybees are utilized to harvest honey from the many flowering plants.
Supporting information
Inventory data references
Information presented was derived from the revised Very Shallow Range Site, literature, limited NRCS clipping data (417s), field observations, and personal contacts with range-trained personnel. Photos by J. L. Schuster.
Other references
Archer, S. 1994. Woody plant encroachment into southwestern grasslands and savannas: Rates, patterns, and proximate causes. Ecological implications of livestock herbivory in the West, 13-68.
Archer, S. and F. E. Smeins. 1991. Ecosystem-level processes. Grazing Management: An Ecological Perspective. Edited by R.K. Heischmidt and J.W. Stuth. Timber Press, Portland, OR.
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. Journal of Range Management, 56(2):114-126.
Bracht, V. 1931. Texas in 1848. German-Texan Heritage Society, Department of Modern Languages, Southwest Texas State University, San Marcos, TX.
Bray, W. L. 1904. The timber of the Edwards Plateau of Texas: Its relations to climate, water supply, and soil. No. 49. US Department of Agriculture, Bureau of Forestry.
Briske, D. D., S. D. Fuhlendorf, and F. E. Smeins. 2005. State-and-transition models, thresholds, and rangeland health: A synthesis of ecological concepts and perspectives. Rangeland Ecology and Management, 58(1):1-10.
Brothers, A., M. E. Ray Jr., and C. McTee. 1998. Producing quality whitetails, revised edition. Texas Wildlife Association, San Antonio, TX.
Brown, J. K. and J. K. Smith. 2000. Wildland fire in ecosystems, effects of fire on flora. Gen. Tech. Rep. RMRS-GTR-42-vol. 2. Ogden, UT: US Department of Agriculture, Forest Service, Rocky Mountain Research Station, 257:42.
Davis, W. B. 1974. The Mammals of Texas. Texas Parks and Wildlife Department, 41.
Foster, J. H. 1917. The spread of timbered areas in central Texas. Journal of Forestry 15(4):442-445.
Frost, C. C. 1998. Presettlement fire frequency regimes of the United States: A first approximation. Fire in ecosystem management: Shifting the paradigm from suppression to prescription. Tall Timbers Fire Ecology Conference Proceedings, 20:70-81.
Gould, F. W. 1975. The grasses of Texas. The Texas Agricultural Experiment Station, Texas A&M University Press, College Station, TX.
Hatch, S. L. and J. Pluhar. 1993. Texas Range Plants. Texas A&M University Press, College Station, TX.
Hamilton, W. and D. Ueckert. 2005. Rangeland woody plant control--past, present, and future. Texas A&M University Press. College Station, TX.
Hart, C. R., A. McGinty, and B. B. Carpenter. 1998. Toxic plants handbook: Integrated management strategies for West Texas. Texas Agricultural Extension Service, The Texas A&M University, College Station, TX.
Heitschmidt, R. K. and J. W. Stuth. 1991. Grazing management: An ecological perspective. Timberline Press, Portland, OR.
Loughmiller, C. and L. Loughmiller. 1984. Texas wildflowers. University of Texas Press, Austin, TX.
Milchunas, D. G. 2006. Responses of plant communities to grazing in the southwestern United States. Gen. Tech. Rep RMRS-GTR-169. Fort Collins, CO: US Department of Agriculture, Forest Service, Rocky Mountain Research Station, 126:169.
Niehaus, T. F. 1998. A field guide to Southwestern and Texas wildflowers (Vol. 31). Houghton Mifflin Harcourt, Boston, MA.
Ramsey, C. W. 1970. Texotics. Texas Parks and Wildlife Department, Austin, TX.
Roemer, F. translated by O. Mueller. 1995. Roemer’s Texas, 1845 to 1847. Texas Wildlife Association, San Antonio, TX.
Scifres, C. J. and W. T. Hamilton. 1993. Prescribed burning for brushland management: The South Texas example. Texas A&M Press, College Station, TX.
Smeins, F. E., S. Fuhlendorf, and C. Taylor, Jr. 1997. Environmental and land use changes: A long term perspective. Juniper Symposium, 1-21.
Taylor, C. A. and F. E. Smeins. 1994. A history of land use of the Edwards Plateau and its effect on the native vegetation. Juniper Symposium, 94:2.
Thurow, T. L. 1991. Hydrology and erosion. Grazing Management: An Ecological Perspective. Edited by R.K. Heitschmidt and J.W. Stuth. Timber Press, Portland, OR.
Tull, D. and G. O. Miller. 1991. A field guide to wildflowers, trees and shrubs of Texas. Texas Monthly Publishing, Houston, TX.
USDA-NRCS. 1997. National range and pasture handbook. Washington, DC: United States Department of Agriculture. Natural Resources Conservation Service, Grazing Lands Technology Institute.
Weniger, D. 1997. The explorers’ Texas: The animals they found. Eakin Press, Austin, TX.
Weniger, D. 1984. The explorers’ Texas: The lands and waters. Eakin Press, Austin, TX.
Vines, R. A. 1984. Trees of Central Texas. University of Texas Press, Austin, TX.
Vines, R. A. 1960. Trees, shrubs and vines of the Southwest. University of Texas Press, Austin, TX.Contributors
Dr. Joseph Schuster, Range & Wildlife Habitat Consultants, LLC, Bryan, TX
Edits by Travis Waiser, MLRA Leader, NRCS, Kerrville, TXApproval
Bryan Christensen, 9/19/2023
Acknowledgments
Technical Review: Charles Anderson, RMS, NRCS, San Angelo, TX Justin Clary, RMS, NRCS, Temple, TX Carol Green, RMS, NRCS, Eldorado, TX Mark Moseley, RMS, NRCS, Boerne, TX Homer Sanchez, RMS, NRCS, Temple, TX QC/QA completed by: Bryan Christensen, SRESS, NRCS, Temple, TX Erin Hourihan, ESDQS, NRCS, Temple, TX
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) Contact for lead author Date 08/26/2026 Approved by Approval date Composition (Indicators 10 and 12) based on Annual Production Indicators
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Number and extent of rills:
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Presence of water flow patterns:
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Number and height of erosional pedestals or terracettes:
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Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
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Number of gullies and erosion associated with gullies:
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Extent of wind scoured, blowouts and/or depositional areas:
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Amount of litter movement (describe size and distance expected to travel):
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Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
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Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
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Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
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Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
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Functional/Structural Groups (list in order of descending dominance by above-ground annual-production or live foliar cover using symbols: >>, >, = to indicate much greater than, greater than, and equal to):
Dominant:
Sub-dominant:
Other:
Additional:
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Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
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Average percent litter cover (%) and depth ( in):
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Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
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Potential invasive (including noxious) species (native and non-native). List species which BOTH characterize degraded states and have the potential to become a dominant or co-dominant species on the ecological site if their future establishment and growth is not actively controlled by management interventions. Species that become dominant for only one to several years (e.g., short-term response to drought or wildfire) are not invasive plants. Note that unlike other indicators, we are describing what is NOT expected in the reference state for the ecological site:
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Perennial plant reproductive capability:
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