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Ecological site R087AY003TX

Claypan Savannah

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): 087A–Texas Claypan Area, Southern Part

This area is entirely in south-central Texas. It makes up about 10,535 square miles (27,295 square kilometers). The towns of Bastrop, Bryan, Centerville, College Station, Ennis, Fairfield, Franklin, Giddings, Gonzales, Groesbeck, La Grange, Madisonville, and Rockdale are in this MLRA. Interstate 45 crosses the northern part of the area, and Interstate 10 crosses the southern part. A number of State Parks are located throughout this area. The parks are commonly associated with reservoirs.

Classification relationships

USDA-Natural Resources Conservation Service, 2006.
-Major Land Resource Area (MLRA) 87A

Ecological site concept

The Claypan Savannah ecological site is characterized by a fine sandy loam surface soil underlain by a dense clay subsoil. This is also the typifying site to which the MLRA derived it's name. The clay subsoil impacts water movement through the soil, which often perches water.

Associated sites

R087AY001TX	Gravelly Gravelly
R087AY002TX	Sandstone Hill Sandstone Hill
R087AY005TX	Sandy Loam Sandy Loam
R087AY006TX	Sandy Sandy
R087AY011TX	Loamy Bottomland Loamy Bottomland
R087AY012TX	Clayey Bottomland Clayey Bottomland

Similar sites

R087BY002TX	Claypan Savannah Different MLRA.
R087AY001TX	Gravelly Gravelly
R087AY005TX	Sandy Loam Sandy Loam

R087BY002TX

Claypan Savannah

Different MLRA.

R087AY001TX

Gravelly

Gravelly

R087AY005TX

Sandy Loam

Sandy Loam

Table 1. Dominant plant species

Tree	(1) Quercus stellata (2) Ulmus alata
Shrub	(1) Ilex vomitoria (2) Callicarpa americana
Herbaceous	(1) Schizachyrium scoparium (2) Sorghastrum nutans

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Physiographic features

This site occurs as nearly level to sloping uplands. Slopes range from 0 to 15 percent, but are generally 1 to 8 percent. The soils are underlain by a dense clay subsoil and during large precipitation events, the sites can briefly pond water. Some sites will have a high water table, which is generally highest in late winter and early spring.

Table 2. Representative physiographic features

Landforms	(1) Plains > Stream terrace (2) Plains > Ridge
Runoff class	Medium to very high
Flooding frequency	None
Ponding duration	Very brief (4 to 48 hours)
Ponding frequency	None to rare
Elevation	200 – 750 ft
Slope	1 – 8%
Ponding depth	3 in
Water table depth	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 duration	Not specified
Ponding frequency	Not specified
Elevation	Not specified
Slope	15%
Ponding depth	Not specified
Water table depth	Not specified

Climatic features

The climate for MLRA 87A is humid subtropical and is characterized by hot summers, especially in July and August, and relatively mild winters. 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 mild days and cool nights. The average annual precipitation in this area is 41 inches. Most of the rainfall occurs in spring and fall. The freeze-free period averages about 276 days and the frost-free period 241 days.

Table 4. Representative climatic features

Frost-free period (average)	241 days
Freeze-free period (average)	276 days
Precipitation total (average)	41 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) BELLVILLE 6NNE [USC00410655], Bellville, TX
(2) GONZALES 1N [USC00413622], Gonzales, TX
(3) LA GRANGE [USC00414903], La Grange, TX
(4) MADISONVILLE [USC00415477], Madisonville, TX
(5) SMITHVILLE [USC00418415], Smithville, TX
(6) CROCKETT [USC00412114], Crockett, TX
(7) FAIRFIELD 3W [USC00413047], Fairfield, TX
(8) COLLEGE STN [USW00003904], College Station, TX
(9) BARDWELL DAM [USC00410518], Ennis, TX
(10) ELGIN [USC00412820], Elgin, TX
(11) FRANKLIN [USC00413321], Franklin, TX
(12) SOMERVILLE DAM [USC00418446], Somerville, TX

Influencing water features

The site can have a high water table. Water tables are most common in the late winter and early spring, or anytime the soil is saturated from large precipitation events.

Wetland description

A stream or wetland does not influence the plant community of this site.

Soil features

The soils are shallow to very deep and typically have fine sandy loam surfaces and dense clay subsoil. The fine sandy loam topsoil ranges from 6 to 15 inches deep but averages less than 10 inches. The surface soil takes in water readily but the clay subsoil is very slowly permeable and restricts air movement and root growth. The very slow permeability and shallow topsoil cause the site to be wet in the winter, slow to warm in the spring, and droughty during the growing season. Low to moderate fertility somewhat limits production on this site. Under good management where herbaceous cover and litter are maintained, rills, gullies, pedestals, and soil compaction layers are not present on the site. Soils correlated to this site include: Arol, Axtell, Burlewash, Chigley, Crockett, Darst, Derly, Edge, Falba, Gredge, Koether, Kurten, Lufkin, Rader, Raino, Rutersville, Sarco, Shalba, Singleton, Singleton, variant, Tabor, Winedale, and Zack.

Table 5. Representative soil features

Parent material	(1) Residuum – sandstone and shale (2) Alluvium – metamorphic and sedimentary rock
Surface texture	(1) Fine sandy loam (2) Loamy fine sand (3) Loam
Family particle size	(1) Clayey
Drainage class	Somewhat poorly drained to moderately well drained
Permeability class	Slow to very slow
Soil depth	15 – 80 in
Surface fragment cover <=3"	1%
Surface fragment cover >3"	1%
Available water capacity (0-40in)	1 – 6 in
Calcium carbonate equivalent (0-40in)	5%
Electrical conductivity (0-40in)	4 mmhos/cm
Sodium adsorption ratio (0-40in)	12
Soil reaction (1:1 water) (0-40in)	4.5 – 7.8
Subsurface fragment volume <=3" (Depth not specified)	5%
Subsurface fragment volume >3" (Depth not specified)	1%

Ecological dynamics

The Claypan Savannah ecological site evolved and was maintained by the grazing and herding effects of native wild large ungulates, periodic fires, and climatic fluctuations. Conversion of this site to cropland and the subsequent abandonment of cropping removed the natural native vegetation, organic matter, fertility, and allowed woody species to invade the site. Continuous grazing by domestic livestock and the suppression of fire on non-cropland sites removes little bluestem (Schizachyrium scoparium), Indiangrass (Sorghastrum nutans), switchgrass (Panicum virgatum), Engelmann's daisy (Engelmannia peristenia), yellow neptunia (Neptunia lutea), and gayfeather (Liatris elegans). Less productive perennial and annual grasses, forbs, vines, and shrubs will replace these plants. With continued continuous grazing, no brush management, and the absence of periodic fires, a community dominated by winged elm (Ulmus alata), eastern persimmon (Diospyros virginiana), mesquite (Prosopis glandulosa), yaupon (Ilex vomitoria), post oak (Quercus stellata), blackjack oak (Quercus marilandica), and eastern red cedar (Juniperus virginiana) will replace the savannah.

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

T1A	-	Heavy continuous grazing, no brush management, abandonment
T1B	-	Brush management, crop cultivation, pasture planting
R2A	-	Brush management, prescribed grazing, prescribed burning
T2A	-	Heavy continuous grazing, no brush management, abandonment
T2B	-	Brush management, crop cultivation, pasture planting
R3A	-	Brush management, range planting, prescribed grazing
T3A	-	Brush management, crop cultivation, pasture planting
R4A	-	Range planting, prescribed grazing, prescribed burning
T4A	-	Heavy continuous grazing, no brush management, abandonment

State 1
Savannah

One community exists in the Savannah State, the 1.1 Tallgrass/Oak Savannah Community. The State is dominated by warm season perennial grasses and the overstory canopy cover is less than 20 percent.

Community 1.1
Tallgrass/Oak Savannah

The interpretive plant community of this site is the reference plant community. This site is a fire-climax savannah of post oak and blackjack oak trees that shade 15 to 20 percent of the ground. The herbaceous component is tall and midgrasses dominated by little bluestem, Indiangrass, and brownseed paspalum (Paspalum plicatulum), which usually make up 50 to 75 percent of the total annual yield. Purpletop tridens (Tridens flavus), Florida paspalum (Paspalum floridanum), switchgrass, tall dropseed (Sporobolus compositus), and thin paspalum (Paspalum setaceum) also occur. Cool-season forage plants occurring on this site include Canada wildrye (Elymus canadensis), Engelmann's daisy, and sedges (Carex spp.). A variety of shrubs, vines, and forbs occur in this community. Grazing prescriptions that permit acceptable grazing periods and allow adequate rest periods with prescribed fire every three to five years are important in the maintenance of the herbaceous plant community and the savannah landscape structure. Continuous overgrazing or over rest and the absence of fire tend to allow a vegetative shift towards woody species such as eastern persimmon, eastern red cedar, and winged elm. Without corrective measures, this shift will continue to the Shrubland State.

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	2250	3400	3675
Tree	450	600	750
Forb	150	300	325
Shrub/Vine	150	200	250
Total	3000	4500	5000

State 2
Shrubland

One community exists in the Shrubland State, the 2.1 Oak Scrub/Shrubland Community. The herbaceous production is not as great compared to the Savannah State, and overstory canopy has increased between 20 and 50 percent.

Community 2.1
Oak Scrub/Shrubland

This plant community is a transitional community between the Savannah and Woodland State. It develops in the absence of fire or mechanical or chemical treatments. It is usually the result of abandonment following cropping or yearly continuous grazing. Trees and shrubs begin to replace the grassland component of the savannah community. In addition to the naturally occurring post oak and blackjack oak, winged elm, water oak (Quercus nigra), mesquite, eastern persimmon, bumelia (Sideroxylon lanuginosum), eastern red cedar, yaupon, and greenbriar (Smilax spp.) increase in density and canopy coverage (20 to 50 percent). Species whose seeds are windblown (elm) or animal dispersed (persimmon, mesquite, eastern red cedar, bumelia) are the first to colonize and dominate the site. Remnants of little bluestem and Indiangrass may still occur but the herbaceous component of the community becomes dominated by lesser producing grasses and forbs. Silver bluestem (Bothriochloa laguroides), tall dropseed, arrowfeather threeawn (Aristida purpurascens), Scribner’s dichanthelium (Dichanthelium oligosanthes), thin paspalum, Hall’s panicum (Panicum hallii), western ragweed (Ambrosia psilostachya), croton (Croton spp.), and narrowleaf sumpweed (Iva angustifolia) commonly occur. If the woody shrub canopy has not exceeded 50 percent, prescribed burning on a three to five year interval in conjunction with prescribed grazing is a viable option for returning this community to a Savannah State that may resemble the reference plant community. If the woody canopy exceeds 50 percent, chemical or mechanical brush control must also be applied to move this transitional community back towards the reference plant community.

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	900	1400	1500
Tree	700	1000	1200
Shrub/Vine	200	300	350
Forb	200	300	350
Total	2000	3000	3400

State 3
Woodland

One community exists in the Woodland State, the Post Oak/Elm Woodland Community. The site is characterized by little herbaceous production. The overstory canopy is over 50 percent and shrubs also limit light to the surface.

Community 3.1
Post Oak/Elm Woodland

This plant community is a closed overstory (50 to 80 percent) woodland dominated by post oak, winged elm, blackjack oak, black hickory (Carya texana), eastern red cedar, and water oak. Understory shrubs and sub-shrubs include yaupon, farkleberry (Vaccinium arboreum), possumhaw (Ilex decidua), and American beautyberry (Callicarpa americana). Woody vines also occur and include Alabama supplejack (Berchemia scandens), poison ivy (Toxicondendron radicans), grape (Vitis spp.), greenbriar, trumpet creeper (Campsis radicans), Virginia creeper (Parthenocissus quinquefolia), and peppervine (Ampelopsis arborea). A herbaceous understory is almost nonexistent but shade tolerant species including longleaf woodoats (Chasmanthium sessiliflorum), broadleaf woodoats (Chasmanthium latifolium), cedar sedge (Carex planostachys), ironweed (Veronia baldwinii), and goldenrod (Solidago spp.) may occur in small amounts. Prescribed fire may be used to convert this site back to the tallgrass/oak savannah but may take many consecutive years of burning due to light fine fuel loads. Chemical brush control on a large scale is usually not a treatment option on this site due to the herbicide resistance of yaupon. Individual plant treatment with herbicides on small acreage may be a viable option. Mechanical treatment of this site, along with seeding, is the most viable option for reversion back to a tallgrass savannah, but the economic viability of this option is questionable.

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)
Tree	1575	2100	2650
Shrub/Vine	500	750	1000
Grass/Grasslike	225	300	375
Forb	75	100	125
Total	2375	3250	4150

State 4
Converted

The Converted Land State contains one community, the 4.1 Converted Land Community. The state is characterized by the land manager farming crops or planted grasses.

Community 4.1
Converted Land

Conversion of this site to cropland occurred from the middle 1800's to the early 1900's. Some remains in cropland today, typically cotton (Gossypium spp.), corn (Zea mays), sorghum (Sorghum spp.), and soybeans (Glycine max). Ditching, land leveling, and levee construction has significantly changed the topography and hydrology on many acres of this site. While restoration of this site to a semblance of the reference plant community is possible with seeding and prescribed grazing, complete restoration of the reference community in a reasonable time is very unlikely. Following crop production, this site is often planted to native or introduced grasses and legumes for livestock grazing or hay production. Typical species planted include improved Bermudagrass varieties, bahiagrass, switchgrass, dallisgrass, kleingrass (Panicum coloratum), old world bluestems (Bothriochloa spp.) annual ryegrass (Lolium multiflorum), and white clover. Many of the introduced species (bahiagrass, Bermudagrass, and dallisgrass) are invasive-moving by wind, water, and animals. Once established, they are extremely difficult to remove and will hinder the reestablishment of native species. The establishment and maintenance of these species requires cultivation, fertilization, weed control, and prescribed grazing management.

Transition T1A
State 1 to 2

The Savannah State will transition to the Shrubland State when continued heavy grazing pressure, no brush management, and/or field abandonment continues. The transition is evident when woody species canopy cover exceeds 20 percent and grasses shift composition to more shade-tolerant species.

Transition T1B
State 1 to 4

The transition to the Converted State occurs when the site is plowed for planting crops or pasture. The driver for the transition is the land manager's decision to farm the site.

Restoration pathway R2A
State 2 to 1

Restoration back to the Savannah State requires brush management, prescribed grazing and/or prescribed fire. Mechanical or chemical controls can be used to remove the woody overstory species and shrubs. Prescribed grazing may require destocking and/or deferment.

Transition T2A
State 2 to 3

The Shrubland State will transition to the Woodland State when continued heavy grazing pressure, no brush management, and/or field abandonment continues. The transition is evident when woody species canopy cover exceeds 50 percent and grasses shift composition to more shade-tolerant species.

Transition T2B
State 2 to 4

The transition to the Converted State occurs when the site is plowed for planting crops or pasture. The driver for the transition is the land manager's decision to farm the site.

Restoration pathway R3A
State 3 to 1

Restoration back to the Savannah State requires substantial energy inputs. Brush management and prescribed grazing will be needed to shift the community back to the reference state. Mechanical or chemical controls can be used to remove the woody overstory species back below 20 percent. Prescribed grazing may require destocking and/or deferment to manage the understory grasses back to those found in the reference community. Fire may be an option, but only if adequate amounts of fine fuel exist in the understory.

Transition T3A
State 3 to 4

The transition to the Converted State occurs when the site is plowed for planting crops or pasture. The driver for the transition is the land manager's decision to farm the site.

Restoration pathway R4A
State 4 to 1

The restoration to State 1 can occur when the land manager ceases agronomic practices. Range planting of native species found in the reference community will be required to bring back a similar community as the State 1 plant composition. The extent of previous soil disturbances will determine how much seedbed preparation will be needed, as well as the ability to be restored. Proper grazing and brush management will be required to ensure success.

Transition T4A
State 4 to 3

The Converted Land State will transition to the Woodland State when continued heavy grazing pressure, no brush management, and/or field abandonment continues. The transition is evident when woody species canopy cover exceeds 50 percent and grasses shift composition to more shade-tolerant species.

Additional community tables

Table 9. Community 1.1 plant community composition

Group	Common name	Symbol	Scientific name	Annual production (lb/acre)	Foliar cover (%)
Grass/Grasslike
1	Tallgrasses			1125–2075
	big bluestem	ANGE	Andropogon gerardii	1125–2075	–
	switchgrass	PAVI2	Panicum virgatum	1125–2075	–
	little bluestem	SCSC	Schizachyrium scoparium	1125–2075	–
	Indiangrass	SONU2	Sorghastrum nutans	1125–2075	–
2	Midgrasses			375–775
	brownseed paspalum	PAPL3	Paspalum plicatulum	375–775	–
	composite dropseed	SPCOC2	Sporobolus compositus var. compositus	375–775	–
3	Midgrasses			225–475
	splitbeard bluestem	ANTE2	Andropogon ternarius	225–475	–
	sideoats grama	BOCU	Bouteloua curtipendula	225–475	–
	silver beardgrass	BOLAT	Bothriochloa laguroides ssp. torreyana	225–475	–
	Florida paspalum	PAFL4	Paspalum floridanum	225–475	–
	purpletop tridens	TRFL2	Tridens flavus	225–475	–
4	Mid/shortgrasses			150–250
	arrowfeather threeawn	ARPU8	Aristida purpurascens	150–250	–
	cedar sedge	CAPL3	Carex planostachys	150–250	–
	longleaf woodoats	CHSE2	Chasmanthium sessiliflorum	150–250	–
	fall witchgrass	DICO6	Digitaria cognata	150–250	–
	Scribner's rosette grass	DIOLS	Dichanthelium oligosanthes var. scribnerianum	150–250	–
	Canada wildrye	ELCA4	Elymus canadensis	150–250	–
	plains lovegrass	ERIN	Eragrostis intermedia	150–250	–
	purple lovegrass	ERSP	Eragrostis spectabilis	150–250	–
	Texas wintergrass	NALE3	Nassella leucotricha	150–250	–
	Florida paspalum	PAFL4	Paspalum floridanum	150–250	–
	Hall's panicgrass	PAHA	Panicum hallii	150–250	–
	vine mesquite	PAOB	Panicum obtusum	150–250	–
	thin paspalum	PASE5	Paspalum setaceum	150–250	–
	longspike tridens	TRST2	Tridens strictus	150–250	–
Forb
5	Forbs			150–250
	Virginia dayflower	COVI3	Commelina virginica	150–250	–
	purple prairie clover	DAPUP	Dalea purpurea var. purpurea	150–250	–
	Illinois bundleflower	DEIL	Desmanthus illinoensis	150–250	–
	ticktrefoil	DESMO	Desmodium	150–250	–
	Engelmann's daisy	ENPE4	Engelmannia peristenia	150–250	–
	Maximilian sunflower	HEMA2	Helianthus maximiliani	150–250	–
	lespedeza	LESPE	Lespedeza	150–250	–
	pinkscale blazing star	LIEL	Liatris elegans	150–250	–
	yellow puff	NELU2	Neptunia lutea	150–250	–
	prairie snoutbean	RHLA5	Rhynchosia latifolia	150–250	–
	fuzzybean	STROP	Strophostyles	150–250	–
	prairie spiderwort	TROC	Tradescantia occidentalis	150–250	–
6	Forb			25–75
	partridge pea	CHFA2	Chamaecrista fasciculata	25–75	–
Shrub/Vine
7	Shrubs/Vines			150–250
	Alabama supplejack	BESC	Berchemia scandens	150–250	–
	American beautyberry	CAAM2	Callicarpa americana	150–250	–
	yaupon	ILVO	Ilex vomitoria	150–250	–
	winged sumac	RHCO	Rhus copallinum	150–250	–
	southern dewberry	RUTR	Rubus trivialis	150–250	–
	cat greenbrier	SMGL	Smilax glauca	150–250	–
	coralberry	SYOR	Symphoricarpos orbiculatus	150–250	–
	farkleberry	VAAR	Vaccinium arboreum	150–250	–
	muscadine	VIRO3	Vitis rotundifolia	150–250	–
Tree
8	Trees			450–750
	black hickory	CATE9	Carya texana	450–750	–
	common hackberry	CEOC	Celtis occidentalis	450–750	–
	blackjack oak	QUMA3	Quercus marilandica	450–750	–
	post oak	QUST	Quercus stellata	450–750	–
	live oak	QUVI	Quercus virginiana	450–750	–
	gum bully	SILAL3	Sideroxylon lanuginosum ssp. lanuginosum	450–750	–
	elm	ULMUS	Ulmus	450–750	–

Interpretations

Animal community

The historic savannah provided habitat to bison, deer, turkey, migratory birds and large predators such as wolves, coyotes, mountain lions, and black bear. White-tailed deer, turkey, coyotes, bobcats, and resident and migratory birds find suitable habitat in these savannahs today. Domestic livestock and exotic ungulates are the dominant grazers and browsers of this site. As the savannah transitions through the various vegetative states towards the woodlands, the quality of the habitat may improve for some species and decline for others. Management must be applied to maintain a vegetative state in optimum habitat quality for the desired animal species.

Hydrological functions

Peak rainfall periods occur in May and June from frontal passage thunderstorms and in September and October from tropical systems as well as frontal passages . Rainfall amounts may be high (three to five per event) and events may become intense. The site is subject to erosion where adequate herbaceous cover is not maintained and on heavy use areas such as roads and livestock trails. Gullies feeding into streams and drains are common on this site where adequate herbaceous cover has not been maintained. Extended periods (60 days) of little to no rainfall during the growing season are common. The hydrology of this site may be manipulated through management to yield higher runoff volumes or greater infiltration to groundwater. Management for less herbaceous cover will favor higher surface runoff while dense herbaceous cover will favor ground water recharge. Potential pollution from sediment, pesticides, and both organic and inorganic fertilizers should always be considered when managing for higher volumes of surface runoff.

Recreational uses

Hunting, camping, bird watching, equestrian, and photography are common activities.

Wood products

Oaks are used for firewood. Hickory and mesquite are used for barbecue wood. Yaupon is used for landscaping.

Other products

Fruit from dewberries, grapes, and plums are harvested.

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 87A.
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. Vines, R.A. 1977. Trees of Eastern Texas. University of Texas Press, Austin, TX. 538 p.
19. Wright, H.A. and A.W. Bailey. 1982. Fire Ecology: United States and Southern Canada. John Wiley & Sons, Inc.

Contributors

Mike Stellbaur
Tyson Hart

Approval

Bryan Christensen, 9/21/2023

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)	Mike Stellbauer, David Polk, and Bill Deauman
Contact for lead author	Mike Stellbauer, Zone RMS, NRCS, Bryan, Texas
Date	06/08/2004
Approved by	Bryan Christensen
Approval date
Composition (Indicators 10 and 12) based on	Annual Production

Indicators

Number and extent of rills:
None.
Presence of water flow patterns:
Some water flow patterns may be present on this site due to landscape position and slopes.
Number and height of erosional pedestals or terracettes:
Pedestals or terracettes would have been very uncommon for this site when occupied by the reference community.
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
Expect no more than 20 percent bare ground distributed in small patches.
Number of gullies and erosion associated with gullies:
Some gullies associated with seeps, springs, and intermittent streams may be present. Head and side slopes should be stable and covered with vegetation.
Extent of wind scoured, blowouts and/or depositional areas:
None.
Amount of litter movement (describe size and distance expected to travel):
This site has slowly permeable sub-soils. On sloping sites, small to medium-sized litter will move short distances with intense storms.
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
Soil surface is resistant to erosion. Stability class range is expected to be 3 to 5.
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
The soil surface is less than 10 inches thick with colors from dark brown sandy loam to dark grayish brown sandy loam and generally week fine granular structure. SOM is 0.5 to 2.0 percent.
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
The savannah of trees, shrubs, vines, grasses, and forbs, along with adequate litter and little bare ground, provides for maximum infiltration and little runoff under normal rainfall events.
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
None.
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:
Warm-season tallgrasses >>

Sub-dominant:
Warm-season midgrasses > Trees >

Other:
Shrubs/Vines > Forbs

Additional:
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
There should be little mortality and decadence for any functional group.
Average percent litter cover (%) and depth ( in):
Litter is primarily herbaceous.
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
3,500 pounds per acre for below average moisture years to 5,500 pounds per acre for above average moisture years.
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:
Potential invasive species include bahiagrass, common Bermudagrass, mesquite, eastern persimmon, eastern red cedar, post oak, winged elm, and yaupon.
Perennial plant reproductive capability:
All perennial plants should be capable of reproducing except for periods of prolonged drought conditions, heavy natural herbivory and intense wildfires.

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Ecosystem states

T1A	-	Heavy continuous grazing, no brush management, abandonment
T1B	-	Brush management, crop cultivation, pasture planting
R2A	-	Brush management, prescribed grazing, prescribed burning
T2A	-	Heavy continuous grazing, no brush management, abandonment
T2B	-	Brush management, crop cultivation, pasture planting
R3A	-	Brush management, range planting, prescribed grazing
T3A	-	Brush management, crop cultivation, pasture planting
R4A	-	Range planting, prescribed grazing, prescribed burning
T4A	-	Heavy continuous grazing, no brush management, abandonment

State 1 submodel, plant communities

1.1. Tallgrass/Oak Savannah

State 2 submodel, plant communities

2.1. Oak Scrub/Shrubland

State 3 submodel, plant communities

3.1. Post Oak/Elm Woodland

State 4 submodel, plant communities

4.1. Converted Land

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Natural ResourcesConservation Service

Ecological site R087AY003TX

Claypan Savannah

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

General information

Figure 1. Mapped extent

MLRA notes

Classification relationships

Ecological site concept

Associated sites

Similar sites

Table 1. Dominant plant species

Ecosystem states

State 1 submodel, plant communities

State 2 submodel, plant communities

State 3 submodel, plant communities

State 4 submodel, plant communities

Natural Resources
Conservation Service

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