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Ecological site R069XY032CO

Sandy Salt Flat

Last updated: 9/07/2023
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): 069X–Upper Arkansas Valley Rolling Plains

MLRA 69 is in the Arkansas Watershed of southeastern (SE) Colorado. It consists of rolling plains, river valleys, and canyonlands. The Arkansas River flows from the Rocky Mountains to Kansas. Tributaries include the Huerfano and Purgatoire Rivers. The MLRA is traversed by Interstate 25 and U.S. Highway 50, and includes the cities of Pueblo, La Junta, and Lamar. Other cities include Cañon City, and Walsenburg. Bent's Fort was once a major trading post along the Santa Fe Trail. The majority of land use is rangeland (greater than 75 percent), and 6 percent cropland. The remainder is urban, recreation, etc. Land ownership is mostly private. Federal lands include U.S. Forest Service Comanche National Grassland, Department of Defense Piñon Canyon Maneuver Site and Fort Carson. There is a minor amount of Bureau of Land Management and other federal land. State areas include Pueblo and John Martin reservoirs. Elevations MLRA-wide are 3,700 to 6,400 feet.

The "Dust Bowl" region (1930s) included SE Colorado, which is periodically affected by severe drought. Dust storms may form during drought years, in windy periods. Annual precipitation is 10 to 16 inches. Precipitation occurs mostly during the growing season, often during rapidly developing thunderstorms. Mean annual air temperature (MAAT) is 48 to 52 degrees Fahrenheit. Summer temperatures may exceed 100 degrees Fahrenheit. Evapotranspiration rates are high. Winter temperatures may be subzero. Snowfall varies from 20 to 40 inches per year. Blizzards can form quickly.

Classification relationships

MLRA 69 is in the Piedmont and Raton Sections of the Great Plains Province. The MLRA is further defined by Land Resource Units (LRUs) A, B, and C. The modal concepts of each LRU can be defined by soil properties and annual precipitation zones (PZ). Other features, such as climate, geology, landforms, and key vegetation, further refine these concepts and are described in the Ecological Site Description (ESD).

LRU A (10 to 12 inches PZ) is 2.4 million acres in the central portion of MLRA 69. There is irrigated cropland in the Arkansas Valley. Precipitation is too limited for dryland crops. Most of LRU A is rangeland, and includes the Comanche National Grassland (FS). This LRU is in portions of Bent, Crowley, Otero, and Pueblo counties. Soil Moisture Regime is Ustic Aridic. The Mean Annual Air Temperature (MAAT) is 51 to 54 degrees Fahrenheit.

LRU B (12 to 14 inches PZ) is 4.7 million acres and includes portions of Baca, Bent, Crowley, El Paso, Fremont, Kiowa, Las Animas, Lincoln, Prowers, and Pueblo counties. Most of the LRU is in rangeland. Land uses include irrigated and dry cropland, small acreage and urban ownership. Land east of Interstate 25 remains largely agricultural. Canyonlands are in the southern half and include Piñon Canyon Maneuver Site and the Picket Wire Canyon of the Comanche National Grasslands. Soil moisture regime is Ustic Aridic. The mean annual air temperature is 50 to 54 degrees Fahrenheit.

The Sandy Salt Flats Ecological Site, LRUs A and B, was developed from an earlier version of the Sandy Salt Flats Ecological Site (2005, revised in 2007). This earlier version of the Sandy Salt Flats Ecological Site (2005) was based on input from Natural Resources Conservation Service (formerly Soil Conservation Service) and historical information obtained from the Sandy Salt Flats Range Site descriptions (1975, revised 1983). This ESD meets the Provisional requirements of the National Ecological Site Handbook (NESH). This ESD will continue refinement towards an Approved status according to the NESH.

Ecological site concept

The Sandy Salt Flat Ecological Site is a run-on site that occurs on terraces and hillslopes of plains. This site is not in a closed depression and has both calcium carbonate and other salts.

Associated sites

R069XY030CO	Salt Meadow The Salt Meadow Ecological Site is commonly adjacent to the Sandy Salt Flat Ecological Site.
R069XY019CO	Deep Sand The Deep Sands Ecological Site is located higher on the landscape and commonly adjacent to the Sandy Salt Flat Ecological Site.
R069XY026CO	Sandy Plains The Sandy Plains Ecological Site is located higher on the landscape and commonly adjacent to the Sandy Salt Flat Ecological Site.
R069XY031CO	Sandy Bottomland The Sandy Bottomland Ecological Site is commonly adjacent to the Sandy Salt Flat Ecological Site.

Similar sites

R069XY033CO	Salt Flat The Sandy Salt Flat Ecological Site has a loamy sand surface texture that the Salt Flat Ecological Site lacks.
R069XY030CO	Salt Meadow The Salt Meadow Ecological Site is directly affected by the water table and has redoximorphic features characterized by mottles in the upper soil horizons.

R069XY033CO

Salt Flat

The Sandy Salt Flat Ecological Site has a loamy sand surface texture that the Salt Flat Ecological Site lacks.

R069XY030CO

Salt Meadow

The Salt Meadow Ecological Site is directly affected by the water table and has redoximorphic features characterized by mottles in the upper soil horizons.

Table 1. Dominant plant species

Tree	Not specified
Shrub	(1) Artemisia filifolia (2) Atriplex canescens
Herbaceous	(1) Sporobolus airoides (2) Bouteloua gracilis

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Physiographic features

This site occurs on plains.

Table 2. Representative physiographic features

Landforms	(1) Terrace (2) Hillslope
Runoff class	Low
Flooding frequency	None
Ponding frequency	None
Elevation	3,700 – 4,100 ft
Slope	2%
Ponding depth	Not specified
Water table depth	60 in
Aspect	Aspect is not a significant factor

Climatic features

Approximately 75 percent of the annual precipitation occurs during the growing season from mid-April to late September. Snowfall can vary greatly from year to year and can range from 20 to 40 inches per year. Winds are estimated to average 6 to 7 miles per hour annually. Daytime winds are generally stronger than nighttime winds. Occasional strong storms may bring brief periods of high winds with gusts to more than 60 miles per hour. The average length of the freeze-free period (28 °F) is 168 days. The average last freeze in the spring is April 22nd, and the average date of first freeze in fall is October 7th. The average length of the frost-free period (32 °F) is 149 days. The last frost in the spring is May 5th, and the average date for first frost in the fall (32 °F), is October 1. July is the hottest month, and January is the coldest. It is not uncommon for temperature to exceed 100 degrees Fahrenheit during the summer. Summer humidity is low and evaporation is high. The winters are characterized with frequent northerly winds, producing severe cold and temperatures dropping to -30 degrees Fahrenheit.

LRU A, in the Arkansas River Valley, is the hottest and driest portion of the MLRA. Mean Annual Precipitation (MAP) is 10 to 12 inches, and Mean Annual Air Temperature (MAAT) is 51 to 54 degrees Fahrenheit. LRU B is the largest extent. MAP is 12 to 14 inches, and MAAT is 50 to 54 degrees Fahrenheit.

Table 3. Representative climatic features

Frost-free period (characteristic range)	127-134 days
Freeze-free period (characteristic range)	149-161 days
Precipitation total (characteristic range)	12-14 in
Frost-free period (actual range)	121-135 days
Freeze-free period (actual range)	141-164 days
Precipitation total (actual range)	11-16 in
Frost-free period (average)	129 days
Freeze-free period (average)	153 days
Precipitation total (average)	13 in

Characteristic range

Actual range

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Figure 2. Monthly precipitation range

Characteristic range

Actual range

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Figure 3. Monthly minimum temperature range

Characteristic range

Actual range

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Figure 4. Monthly maximum temperature range

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Figure 5. Monthly average minimum and maximum temperature

Figure 6. Annual precipitation pattern

Figure 7. Annual average temperature pattern

Climate stations used

(1) CHERAW 1 N [USC00051539], La Junta, CO
(2) ORDWAY 21 N [USC00056136], Ordway, CO
(3) ROCKY FORD 2 SE [USC00057167], Rocky Ford, CO
(4) PUEBLO MEM AP [USW00093058], Pueblo, CO
(5) ORDWAY 2 ENE [USC00056131], Ordway, CO
(6) TACONY 13 SE [USC00058157], Boone, CO
(7) LA JUNTA 20 S [USC00054726], La Junta, CO
(8) EADS [USC00052446], Eads, CO
(9) PUEBLO RSVR [USC00056765], Pueblo, CO

Soil features

The soils of this site are very deep. They are well drained with moderately slow to rapid permeability. The surface layer thickness ranges from 9 to 11 inches. The soil moisture regime is ustic aridic. The soil temperature regime is mesic. Parent material originated from mixed sources.

Major soil series correlated to this ecological site include Keyner.

Revisions to soil surveys are on-going. For the most recent updates, visit the Web Soil Survey, the official site for latest soils information: http://websoilsurvey.nrcs.usda.gov/app/WebSoilSurvey.aspx.

Table 4. Representative soil features

Parent material	(1) Eolian deposits (2) Alluvium
Surface texture	(1) Loamy sand
Family particle size	(1) Sandy
Drainage class	Well drained
Permeability class	Moderately slow to rapid
Soil depth	60 – 80 in
Surface fragment cover <=3"	Not specified
Surface fragment cover >3"	Not specified
Available water capacity (0-40in)	2 – 8 in
Calcium carbonate equivalent (0-40in)	14%
Electrical conductivity (0-40in)	2 – 16 mmhos/cm
Sodium adsorption ratio (0-40in)	25
Soil reaction (1:1 water) (0-40in)	7.4 – 9.6
Subsurface fragment volume <=3" (Depth not specified)	Not specified
Subsurface fragment volume >3" (Depth not specified)	Not specified

Ecological dynamics

The information in this ESD, including the state-and-transition model (STM), was developed using archeological and historical data, professional experience, and scientific studies. The information is representative of a complex set of plant communities. The plant composition has been determined by study of rangeland relic areas, areas protected from excessive disturbance, seasonal-use pastures, short-duration or time-controlled grazing strategies, and historical accounts.

Not all scenarios or plants are included. Key indicator plants, animals, and ecological processes are described to inform land management decisions.

This region was historically occupied by large grazing animals, such as bison, along with pronghorn and mule deer. Deer and pronghorn are widely distributed throughout the MLRA. This is an important site for livestock grazing, especially cattle.

Drought has historically impacted the vegetation of this region. Changes in species composition vary depending upon the duration and severity of the drought cycle and prior grazing management. Recent drought events have increased mortality of blue grama significantly in some locales, along with other bunchgrasses, such as sand bluestem, little bluestem, needle and thread, Fendler threeawn, and squirreltail. Historic fire frequency (pre-industrial) is estimated at 15 to 20 years (Guyette, 2012), randomly distributed, and started by lightning at various times throughout the growing season. Early human inhabitants were also likely to start fires (deliberate or accidental).

The site is dominated by warm-season mid bunchgrass (alkali sacaton), and warm-season tall bunchgrasses (switchgrass, sand bluestem), cool-season mid rhizomatous grass (western wheatgrass), and warm-season short bunchgrass (blue grama). Secondary grasses are cool-season mid bunchgrass (needle and thread), warm-season mid rhizomatous grass (galleta), warm-season short rhizomatous grass (inland saltgrass), and warm-season tall rhizomatous grass (prairie sandreed). Minor grasses include cool-season mid bunchgrass (Indian ricegrass), and warm-season mid bunchgrasses (little bluestem, sideoats grama, sand dropseed). Other minor grasses and grass-like plants that occur in small amounts are bottlebrush squirreltail, threeawn, ring muhly, annual barley, sixweeks fescue, and sun sedge. Various shrubs (fourwing saltbush, winterfat, sand sagebrush, rabbitbrush) and forbs (dotted gayfeather, silky prairie clover, annual buckwheat, lemon scurfpea) also occur on the site.

Recurring seasonal herbivory without adequate recovery opportunity, and extended drought degrade. Grasses such as alkali sacaton, western wheatgrass, switchgrass, and sand bluestem decrease in frequency and production as do key shrubs (fourwing saltbush and winterfat). Blue grama and inland saltgrass increase. Forbs such as dotted gayfeather and purple prairie clover also decrease. Slick spots (high sodium areas of bare ground) increase. Continuous grazing without adequate recovery opportunity can eventually remove mid and tallgrasses from the plant community as blue grama and inland saltgrass become dominant and eventually form a sod-bound appearance. Over the long-term, continuous use without adequate recovery opportunity or long term non-use and lack of fire will result in large amounts of bare ground. Sand dropseed, annuals, and bare ground increase with long-term continuous grazing. Species such as red threeawn, ring muhly, broom snakeweed, and annuals increase. Slick spots become enlarged and connected by flow paths. Non-use in the absence of fire will result in excessive litter and reduced plant density.

Drier and warmer climatic conditions exist in the central portion of MLRA 69. This area includes the eastern half of Pueblo county, northern Otero, extreme northwestern Bent, western edge of Kiowa, southern edge of Lincoln and all of Crowley County. These conditions are primarily caused by a rain shadow effect from the southern Rocky Mountains. Evapotranspiration rates (atmospheric demand) are higher in this area of MLRA 69. Total annual production is typically lower.

Southeastern Colorado was strongly affected by extended drought conditions in the “Dust Bowl” period of the 1930s, with recurrent drought cycles in the 1950s and 1970s. Extreme to exceptional drought conditions have re-visited the area from 2002 to 2012, with brief interludes of near normal to normal precipitation years. “During periods of drought, high winds give rise to the dust storms which are especially characteristic of the southeastern plains (WRCC, 2022).” Recent drought events have increased mortality of blue grama upwards of 80 percent in some locales. The long-term effects of these latest drought years have yet to be determined.

Growth of native cool-season plants begins about April 15 and continues to mid-June. Native warm-season plants begin growth about May 1 and continue to about August 15. Regrowth of cool-season plants occurs in September and October in most years, depending on moisture. For detailed information, visit the Western Regional Climate Center website at https://wrcc.dri.edu/.

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. Reference State

2. Blue Grama-Inland Saltgrass Dominant State

3. Eroded State

T1A	-	Continuous, heavy grazing. Lack of fire.
R2A	-	Prescribed grazing. Prescribed fire.
T2A	-	Continuous, heavy grazing. Lack of fire.

State 1 submodel, plant communities

1.1. Sporobolus airoides-Bouteloua gracilis (alakli sacaton-blue grama).

1.2. Bouteloua gracilis-Pascopyrum smithii (blue grama-western wheatgrass).

1.3. Sporobolus airoides-Bouteloua gracilis (alakali sacaton-blue grama) Excessive Litter Community.

1.1A	-	Continuous, heavy grazing. Lack of fire.
1.1B	-	Non-use. Lack of fire.
1.2A	-	Prescribed grazing. Prescribed fire.
1.3A	-	Prescribed grazing. Prescribed fire.

State 2 submodel, plant communities

2.1. Bouteloua gracilis-Distichlis spicata (blue grama-inland saltgrass).

State 3 submodel, plant communities

3.1. Sporobolus cryptandrus-Distichlis spicata (sand dropseed-inland saltgrass).

State 1
Reference State

The Reference State is characterized by three community phases that exist within the natural range of variability for the site. These phases are maintained by a historic fire frequency (estimated to be on 15 to 20 year intervals), herbivory by large ungulates, and adequate recovery opportunity. High production of perennial grasses and extensive soil cover allow for increased soil moisture retention, vegetative production, and overall soil quality.

Dominant plant species

sand sagebrush (Artemisia filifolia), shrub
fourwing saltbush (Atriplex canescens), shrub
winterfat (Krascheninnikovia lanata), shrub
alkali sacaton (Sporobolus airoides), grass
blue grama (Bouteloua gracilis), grass
switchgrass (Panicum virgatum), grass
western wheatgrass (Pascopyrum smithii), grass

Community 1.1
Sporobolus airoides-Bouteloua gracilis (alakli sacaton-blue grama).

This is the interpretive plant community and is considered to be the reference plant community. This plant community developed with herbivory by large grazing transient herbivores with adequate recovery opportunity. This community consists chiefly of tall and mid-warm and cool-season grasses. The landscape is undulating sand over fine textured alluvium. The potential vegetation is about 85 to 90 percent grasses and grass-like plants, 5 to 10 percent forbs, and 5 to 15 percent shrubs by air-dry weight. Principal dominant grasses consist of alkali sacaton, sand bluestem, switchgrass, western wheatgrass, and blue grama. Secondary grasses and grass-like plants are inland saltgrass, prairie sandreed, sand dropseed, little bluestem, and sun sedge. Forbs and shrubs such as silky prairie clover, prairie spiderwort, purple prairie clover, ironplant, goldenweed, Louisiana sagewort, dotted gayfeather, sand sagebrush, and rabbitbrush are common. This plant community is diverse, stable, and productive. Litter is properly distributed with very little movement off-site and natural plant mortality is very low. It is well suited to carbon sequestration, water yield, wildlife use by many species, livestock use, and is aesthetically pleasing. Community dynamics, nutrient cycle, water cycle, and energy flow are functioning properly. This community is resistant to many disturbances with the exception of heavy, continuous grazing, tillage, and development into urban or other uses. Production in this community can vary from 700 to 2000 pounds of air-dry vegetation per acre per year depending on the weather and averages 1300 pounds.

Dominant plant species

sand sagebrush (Artemisia filifolia), shrub
fourwing saltbush (Atriplex canescens), shrub
winterfat (Krascheninnikovia lanata), shrub
alkali sacaton (Sporobolus airoides), grass
blue grama (Bouteloua gracilis), grass
switchgrass (Panicum virgatum), grass
western wheatgrass (Pascopyrum smithii), grass

Figure 8. 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	580	1072	1665
Shrub/Vine	60	130	200
Forb	60	98	135
Total	700	1300	2000

Figure 9. Plant community growth curve (percent production by month). CO6905, Warm-season dominant, cool-season sub-dominant; MLRA-69; upland coarse-textured soils.

Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
J	F	M	A	M	J	J	A	S	O	N	D
0	0	5	10	22	35	15	10	3	0	0	0

Community 1.2
Bouteloua gracilis-Pascopyrum smithii (blue grama-western wheatgrass).

This community developed with recurring heavy, seasonal herbivory with inadequate recovery opportunity. Plant frequency has decreased, but the overall integrity of the vegetation remains intact. Tall and mid warm-season grasses such as alkali sacaton, sand bluestem, and switchgrass are present but in decreased amounts compared to the reference plant community. Blue grama and inland saltgrass have increased. Western wheatgrass is still present and may have increased slightly. Total above ground carbon has been lost due to decreases in forage and litter production. Reduction of deep-rooted tallgrasses, forbs, and shrubs, and increased warm-season shortgrasses has begun to alter the biotic integrity of this community. Water and nutrient cycles may become impaired. Slick spots (bare high sodium areas) may be increasing. Production in this community can vary from 400 to 1200 pounds of air-dry vegetation per acre per year depending on the weather and averages 700 pounds.

Dominant plant species

sand sagebrush (Artemisia filifolia), shrub
rubber rabbitbrush (Ericameria nauseosa ssp. nauseosa var. glabrata), shrub
blue grama (Bouteloua gracilis), grass
western wheatgrass (Pascopyrum smithii), grass
saltgrass (Distichlis spicata), grass

Figure 10. Plant community growth curve (percent production by month). CO6905, Warm-season dominant, cool-season sub-dominant; MLRA-69; upland coarse-textured soils.

Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
J	F	M	A	M	J	J	A	S	O	N	D
0	0	5	10	22	35	15	10	3	0	0	0

Community 1.3
Sporobolus airoides-Bouteloua gracilis (alakali sacaton-blue grama) Excessive Litter Community.

This plant community occurs when herbivory is removed for long periods of time in the absence of fire. Plant composition is similar to the Reference Plant Community, however, individual species production and frequency are reduced. Many of the nutrients are tied up in excessive litter. The semiarid environment and the absence of animal traffic to break down litter slow nutrient recycling. Aboveground litter also limits sunlight from reaching plant crowns. Many plants, especially bunchgrasses (alkali sacaton, switchgrass) die off. Thick litter and absence of grazing animals (animal impact) or fire reduce seed germination and establishment. In advanced stages, plant mortality can increase and erosion may eventually occur if bare ground increases. Total annual production ranges from 200 to 1100 pounds of air-dry vegetation per acre per year.

Dominant plant species

sand sagebrush (Artemisia filifolia), shrub
fourwing saltbush (Atriplex canescens), shrub
winterfat (Krascheninnikovia lanata), shrub
alkali sacaton (Sporobolus airoides), grass
blue grama (Bouteloua gracilis), grass
switchgrass (Panicum virgatum), grass
western wheatgrass (Pascopyrum smithii), grass

Figure 11. Plant community growth curve (percent production by month). CO6906, Warm-season dominant, cool-season sub-dominant, excess litter; MLRA-69; upland coarse-textured soils.

Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
J	F	M	A	M	J	J	A	S	O	N	D
0	0	5	10	25	30	15	10	3	2	0	0

Pathway 1.1A
Community 1.1 to 1.2

Heavy, season-long herbivory without adequate recovery opportunity between grazing events and lack of fire shift this community to the 1.2 community.

Conservation practices

Prescribed Burning
Prescribed Grazing

Pathway 1.1B
Community 1.1 to 1.3

Non-use or absence of fire moves the reference community to the 1.3 community.

Conservation practices

Prescribed Burning
Prescribed Grazing

Pathway 1.2A
Community 1.2 to 1.1

Seasonal herbivory with adequate recovery opportunity between grazing events, and animal-forage balance move this plant community back to the reference plant community. Prescribed fire accelerates this process.

Conservation practices

Prescribed Burning
Prescribed Grazing

Pathway 1.3A
Community 1.3 to 1.1

Herbivory with adequate recovery opportunity or fire restores this plant community back to the reference plant community.

Conservation practices

Prescribed Burning
Prescribed Grazing

State 2
Blue Grama-Inland Saltgrass Dominant State

The Blue Grama-Inland Saltgrass Dominant State contains one community phase. This is a very stable state that is resistant to change due to the high tolerance of blue grama and inland saltgrass to grazing. The loss of dominant and sub-dominant functional/structural groups such as cool-season grasses, nitrogen fixing legumes, and shrubs reduces the biodiversity and productivity of this site.

Dominant plant species

sand sagebrush (Artemisia filifolia), shrub
blue grama (Bouteloua gracilis), grass
saltgrass (Distichlis spicata), grass

Community 2.1
Bouteloua gracilis-Distichlis spicata (blue grama-inland saltgrass).

This plant community developed with heavy, continuous grazing, and has crossed an ecological threshold. Blue grama and inland saltgrass are the dominant species. Sand bluestem and switchgrass have been removed. Western wheatgrass and alkali sacaton may persist in remnant amounts. Overall plant diversity and biotic integrity have been significantly reduced. The water and nutrient cycles, energy flow dynamics, and organic matter levels have been significantly impacted. Slick spots (bare areas between blue grama and saltgrass plants) have increased in size. Wind-blown salts and soil can accelerate formation of slick spots. Flow paths may be forming. Production in this community can vary from 150 to 600 pounds of air-dry vegetation per acre per year depending on the weather and averages 300 pounds.

Dominant plant species

sand sagebrush (Artemisia filifolia), shrub
rubber rabbitbrush (Ericameria nauseosa ssp. nauseosa var. glabrata), shrub
blue grama (Bouteloua gracilis), grass
saltgrass (Distichlis spicata), grass

Figure 12. Plant community growth curve (percent production by month). CO6907, Warm-season dominant; MLRA-69; upland coarse-textured soils.

Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
J	F	M	A	M	J	J	A	S	O	N	D
0	0	0	5	30	40	20	5	0	0	0	0

State 3
Eroded State

In the Eroded State, inland saltgrass is present, but the more palatable species have been replaced by sand dropseed and annual grasses. Accelerated soil loss is a major concern. Wind scoured areas may be apparent as regression proceeds. Bare ground is becoming more apparent and slick spots have enlarged and are connected by flow paths. Soil stability, plant diversity, and productivity are lacking. Nutrient cycle, water cycle, energy flow, and community dynamics are severely impacted. Desertification is well advanced. The Reference State ecosystem has been driven beyond the limits of ecological resilience and has crossed a threshold. The designation "Eroded State" denotes complete deterioration of ecological processes.

Dominant plant species

sand sagebrush (Artemisia filifolia), shrub
rubber rabbitbrush (Ericameria nauseosa ssp. nauseosa var. glabrata), shrub
sand dropseed (Sporobolus cryptandrus), grass
saltgrass (Distichlis spicata), grass
cheatgrass (Bromus tectorum), grass
Russian thistle (Salsola), other herbaceous

Community 3.1
Sporobolus cryptandrus-Distichlis spicata (sand dropseed-inland saltgrass).

Inland saltgrass persists in localized areas. Sand dropseed and annual plants such as sixweeks fescue, cheatgrass, Russian thistle, and burningbush have increased or invaded. Production in this community can vary from 50 to 200 pounds of air-dry vegetation per acre per year.

Dominant plant species

sand sagebrush (Artemisia filifolia), shrub
rubber rabbitbrush (Ericameria nauseosa ssp. nauseosa var. glabrata), shrub
sand dropseed (Sporobolus cryptandrus), grass
saltgrass (Distichlis spicata), grass
cheatgrass (Bromus tectorum), grass
Russian thistle (Salsola), other herbaceous

Figure 13. Plant community growth curve (percent production by month). CO6905, Warm-season dominant, cool-season sub-dominant; MLRA-69; upland coarse-textured soils.

Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
J	F	M	A	M	J	J	A	S	O	N	D
0	0	5	10	22	35	15	10	3	0	0	0

Transition T1A
State 1 to 2

Continuous, heavy grazing without adequate recovery opportunity following each grazing event and lack of fire shift this state to the Blue Grama-Inland Saltgrass Dominant State.

Conservation practices

Prescribed Burning
Prescribed Grazing

Restoration pathway R2A
State 2 to 1

Long-term prescribed grazing with adequate recovery opportunity between grazing events shifts this state to the Reference State. Prescribed fire accelerates this process.

Conservation practices

Prescribed Burning
Prescribed Grazing

Transition T2A
State 2 to 3

Continuous, heavy grazing without adequate recovery opportunity between grazing events and lack of fire moves this plant community across an ecological threshold to the Eroded State.

Additional community tables

Table 6. Community 1.1 plant community composition

Group	Common name	Symbol	Scientific name	Annual production (lb/acre)	Foliar cover (%)
Grass/Grasslike
1				1105–1170
	alkali sacaton	SPAI	Sporobolus airoides	325–455	–
	blue grama	BOGR2	Bouteloua gracilis	195–325	–
	switchgrass	PAVI2	Panicum virgatum	130–260	–
	western wheatgrass	PASM	Pascopyrum smithii	130–195	–
	sand bluestem	ANHA	Andropogon hallii	130–195	–
	saltgrass	DISP	Distichlis spicata	15–65	–
	needle and thread	HECOC8	Hesperostipa comata ssp. comata	40–65	–
	prairie sandreed	CALO	Calamovilfa longifolia	15–40	–
	James' galleta	PLJA	Pleuraphis jamesii	15–40	–
	Grass, perennial	2GP	Grass, perennial	15–40	–
	composite dropseed	SPCOC2	Sporobolus compositus var. compositus	15–40	–
	sand dropseed	SPCR	Sporobolus cryptandrus	15–25	–
	Indian ricegrass	ACHY	Achnatherum hymenoides	0–25	–
	sun sedge	CAINH2	Carex inops ssp. heliophila	15–25	–
	sideoats grama	BOCU	Bouteloua curtipendula	0–25	–
	buffalograss	BODA2	Bouteloua dactyloides	0–25	–
	little bluestem	SCSC	Schizachyrium scoparium	0–25	–
	squirreltail	ELELE	Elymus elymoides ssp. elymoides	0–25	–
	ring muhly	MUTO2	Muhlenbergia torreyi	0–15	–
	Fendler threeawn	ARPUL	Aristida purpurea var. longiseta	0–15	–
Forb
2				65–130
	Forb, perennial	2FP	Forb, perennial	10–65	–
	silky prairie clover	DAVI	Dalea villosa	10–25	–
	dotted blazing star	LIPU	Liatris punctata	10–25	–
	lacy tansyaster	MAPIP4	Machaeranthera pinnatifida ssp. pinnatifida var. pinnatifida	0–10	–
	tenpetal blazingstar	MEDE2	Mentzelia decapetala	0–10	–
	whitest evening primrose	OEAL	Oenothera albicaulis	0–10	–
	beardtongue	PENST	Penstemon	0–10	–
	lemon scurfpea	PSLA3	Psoralidium lanceolatum	0–10	–
	slimflower scurfpea	PSTE5	Psoralidium tenuiflorum	0–10	–
	scarlet globemallow	SPCO	Sphaeralcea coccinea	0–10	–
	prairie spiderwort	TROC	Tradescantia occidentalis	0–10	–
	annual buckwheat	ERAN4	Eriogonum annuum	0–10	–
	shaggy dwarf morning-glory	EVNU	Evolvulus nuttallianus	0–10	–
	bush morning-glory	IPLE	Ipomoea leptophylla	0–10	–
	Cuman ragweed	AMPS	Ambrosia psilostachya	0–10	–
	white sagebrush	ARLU	Artemisia ludoviciana	0–10	–
	woolly locoweed	ASMO7	Astragalus mollissimus	0–10	–
	Texas croton	CRTE4	Croton texensis	0–10	–
	purple prairie clover	DAPUP	Dalea purpurea var. purpurea	0–10	–
Shrub/Vine
3				65–195
	Shrub (>.5m)	2SHRUB	Shrub (>.5m)	15–65	–
	sand sagebrush	ARFI2	Artemisia filifolia	15–40	–
	fourwing saltbush	ATCA2	Atriplex canescens	15–40	–
	winterfat	KRLA2	Krascheninnikovia lanata	15–40	–
	rubber rabbitbrush	ERNAG	Ericameria nauseosa ssp. nauseosa var. glabrata	15–25	–
	broom snakeweed	GUSA2	Gutierrezia sarothrae	0–15	–
	plains pricklypear	OPPO	Opuntia polyacantha	0–15	–
	soapweed yucca	YUGL	Yucca glauca	0–15	–
	spreading buckwheat	EREF	Eriogonum effusum	0–15	–

Interpretations

Animal community

WILDLIFE INTERPRETATIONS:
The variety of grasses, forbs, and shrubs on this ecological site in the various plant communities provides habitat for a wide range of wildlife species. Historic large grazers that influenced these plant communities were bison, elk, and pronghorn. Changes over time have resulted in the loss of bison, the reduction in elk numbers, and pronghorn population swings. Domestic grazers now share these habitats with wildlife. The grassland communities of eastern Colorado are home to many bird species. Changes in the composition of the plant community when moving from the reference plant community to other communities on this ecological site may result in dramatic species shifts in the bird community. Because of a lack of permanent water, fish and many amphibians are not expected on this ecological site. Mule and white-tailed deer may use this ecological site, however the shrub cover is too low to expect more than occasional use. The gray wolf and wild bison used this ecological site in historic times. The wolf is thought to be extirpated from Eastern Colorado. Bison in the area are domesticated.

Reference Plant Community:
The structural diversity in the plant community found on the reference plant community is attractive to a number of wildlife species. Common bird species expected include Cassin’s and Brewer's sparrow, lark bunting, western meadowlark, and ferruginous and Swainson’s hawks. The combination of mid and tallgrasses and shrubs provides habitat for lesser prairie chicken in the eastern parts of this site. Scaled quail are expected to use this community.

White-tailed and black-tailed jackrabbit, badger, pronghorn, coyote, swift fox, plains pocket gopher, long-tailed weasel, and several species of mice are mammals that commonly use this plant community. Reptiles include western rattlesnake, bullsnake, western hognose snake, racer, western box turtle, and six-lined racerunner.

1.2 Plant Community:
All wildlife species are expected in this plant community. However, the loss of some of the vegetative structural diversity makes it less attractive to the reference plant community species.

1.3 - 2.1 Communities:
The lack of shrubs and taller grasses in these plant communities results in a shift of bird species. With the exception of the hawk species, most reference plant community bird species would be only occasional users of these communities, and only on sites with adequate drainage. The typical shortgrass prairie species such as horned lark, killdeer, long-billed curlew, mountain plover, and ferruginous hawk are the dominant species.

Black-tailed jackrabbit and black-tailed prairie dog may frequent these communities along with mammal species common to the reference plant community. Reptiles using these communities are short-horned lizard, the lesser earless lizard, and the species listed for the reference plant community.

3.1 Community:
The presence of tall species such as kochia, Russian thistle, sand dropseed, and other invaders in this community limit use by mountain plover and other species requiring unobstructed visual distances. Most reference plant community species are not expected here because of the change in vegetative structure.

GRAZING INTERPRETATIONS:
The following table lists suggested initial stocking rates for an animal unit (1000 pound beef cow) under continuous grazing (yearlong grazing or growing-season-long grazing) based on normal growing conditions. However, continuous grazing is not recommended. These estimates should only be used as preliminary guidelines in the initial stages of the conservation planning process. Often, the existing plant composition does not entirely match any particular plant community described in this ecological site description. Therefore, field inventories are always recommended to document plant composition, total production, and palatable forage production. Carrying capacity estimates that reflect on-site conditions should be calculated using field inventories.

If the following production estimates are used, they should be adjusted based on animal kind or class and on the specific palatability of the forage plants in the various plant community descriptions. Under a properly stocked, properly applied, prescribed grazing management system that provides adequate recovery periods following each grazing event, improved harvest efficiencies eventually result in increased carrying capacity. See USDA-NRCS Colorado Prescribed Grazing Standard and Specification Guide (528).

The stocking rate calculations are based on the total annual forage production in a normal year multiplied by 25 percent harvest efficiency divided by 912.5 pounds of ingested air-dry vegetation for an animal unit per month (AUM).

Plant Community Production (lbs./acre) and Stocking Rate (AUM/acre)

Reference Plant Community - (1300) (0.36)

1.2 Plant Community - (700) (0.19)

2.1 - (300) (0.08)

All stocking rates are guidelines and actual stocking rates should be determined on-site for planning purposes.

Grazing by domestic livestock is one of the major income-producing industries in the area. Rangelands in this area provide yearlong forage under prescribed grazing for cattle, sheep, horses, and other herbivores.

Hydrological functions

Water is the principal factor limiting forage production on this site. This site is dominated by soils in hydrologic group A. Infiltration is high and runoff potential for this site varies from moderate to high depending on ground cover. Areas where ground cover is less than 50 percent have the greatest potential to have reduced infiltration and higher runoff (refer to NRCS Section 4, National Engineering Handbook (USDA–NRCS, 1972–2012) for runoff quantities and hydrologic curves).

Recreational uses

This site provides hunting, hiking, photography, bird watching, and other opportunities. The wide varieties of plants that bloom from spring until fall have an aesthetic value that appeals to visitors.

Wood products

None noted.

Other products

Site Development and Testing Plan:

General Data (MLRA and Revision Notes, Hierarchical Classification, Ecological Site Concept, Physiographic, Climate, and Water Features, and Soils Data):Updated. All “Required” items are complete to Provisional level.

Community Phase Data (Ecological Dynamics, STM, Transition & Recovery Pathways, Reference Plant Community, Species Composition List, Annual Production Table):

Updated. All “Required” items are complete to Provisional level.
NOTE: Annual Production Table and Species Composition List are from the “Previously Approved” ESD (2004). These need review for future updates at the next Approved level. Minor edit was made to Species Composition List.

Each Alternative State/Community:Complete to Provisional level. Narrative for each state and community has been updated.

Action Item: Need to find supporting data for The Sand Sagebrush and Grass Dominant Plant Communities. Further group discussion is needed.

Supporting Information (Site Interpretations, Assoc. & Similar Sites, Inventory Data References, Agency/State Correlation, References):
Updated. All “Required” items are complete to Provisional level.

Animal CommunityWildlife Interpretations:First “overview” paragraph retained.
Individual Plant Community phase interpretations are removed and need to be updated at next “Approved” level.

Livestock Interpretations:
Updated to reflect the plant community name revisions. The Stocking rate calculations remain the same because they are based on the “Legacy” Total Annual Production table.
The stocking rate calculations need to be updated when Total Annual Production and Plant Community annual production is revised at the next “Approved” level.

Hydrology:
From “Previously Approved” ESD (2004). This needs to be updated at next “approved” level.

Other Site Interpretation:
Recreational Uses, Wood Products, Other Products, and Plant Preferences table, and Rangeland Health Reference Sheet carried over from “Previously Approved” ESD (2004).

Other information

Relationship to Other Classifications:
NRCS Classification Hierarchy:
Physiographic Divisions of the United States (Fenneman, 1946): Physiographic DivisionPhysiographic ProvincePhysiographic SectionLand Resource RegionMajor Land Resource Area (MLRA)Land Resource Unit (LRU).

USFS Classification Hierarchy:
National Hierarchical Framework of Ecological Units (Cleland et al, 181-200):
DomainDivisionProvinceSectionSubsectionLandtype Association LandtypeLandtype Phase.

Supporting information

Inventory data references

NRI: references to Natural Resource Inventory data
Information presented here has been derived from data collection on private and federal lands using:
• Double Sampling (clipped 2 of 5 plots)*
• Rangeland Health (Pellant et al., 2005)
• Soil Stability (Pellant et al., 2005)
• Line Point Intercept : Foliar canopy, basal cover (Forb, Graminoid, Shrub, subshrub, Lichen, Moss, Rock fragments, bare ground, % Litter) (Herrick et al., 2005)
• Soil pedon descriptions collected on site (Schoeneberger et al., 2012)

*NRCS double-sampling method, CO NRCS Similarity Index Worksheet 528(1).
Additional reconnaissance data collection using numerous ocular estimates and other inventory data; NRCS clipping data for USDA program support; Field observations from experienced range trained personnel. Specific data information is contained in individual landowner/user case files and other files located in county NRCS field offices.

References

Guyette, R.P., M.C. Stambaugh, D.C. Dey, and R. Muzika. 2012. Predicting Fire Frequency with Chemistry and Climate. Ecosystems 15:322–335.

Other references

Data collection for this ecological site was done in conjunction with the progressive soil surveys within the Upper Arkansas Valley (MLRA 69) of Colorado. The site has been mapped and correlated with soils in the following soil surveys: Baca County, Bent County, Crowley County, El Paso County Area, Fremont County Area, Huerfano County Area, Kiowa County, Las Animas County: Parts of Huerfano and Las Animas, Lincoln County, Otero County, Prowers County, and Pueblo Area: Parts of Pueblo and Custer Counties.

30 Year Climatic and Hydrologic Normals (1981-2010) Reports. National Water and climate Center: Portland, OR. August 2015

ACIS-USDA Field Office Climate Data (WETS), period of record 1971-2000 http://agacis.rcc-acis.org (powered by WRCC) Accessed March 2016

Andrews, R. and R. Righter. 1992. Colorado Birds. Denver Museum of Natural History, Denver, CO. 442

Armstrong, D.M. 1972. Distribution of mammals in Colorado. Univ. Kansas Museum Natural History Monograph #3. 415.

Butler, LD., J.B. Cropper, R.H. Johnson, A.J. Norman, G.L. Peacock, P.L. Shaver, and K.E. Spaeth. 1997, revised 2003. National Range and Pasture Handbook. National Cartography and Geospatial Center’s Technical Publishing Team: Fort Worth, TX. http://www.glti.nrcs.usda.gov/technical/publications/nrph.html Accessed August 2015

Clark, J., E. Grimm, J. Donovan, S. Fritz, D. Engrstom, and J. Almendinger. 2002. Drought cycles and landscape responses to past Aridity on prairies of the Northern Great Plains, USA. Ecology, 83(3), 595-601.

Cleland, D., P. Avers, W.H. McNab, M. Jensen, R. Bailey, T. King, and W. Russell. 1997. National Hierarchical Framework of Ecological Units, published in Ecosystem Management: Applications for Sustainable Forest and Wildlife Resources, Yale University Press

Cooperative climatological data summaries. NOAA. Western Regional Climate Center: Reno, NV. Web. http://www.wrcc.dri.edu/climatedata/climsum Accessed August 2015

Egan, Timothy. 2006. The Worst Hard Time. Houghton Mifflin Harcourt Publishing Company: New York, NY.

Fitzgerald, J.P., C.A. Meaney, and D.M. Armstrong. 1994. Mammals of Colorado. Denver Museum of Natural History, Denver, CO. 467. Hammerson, G.A. 1986. Amphibians and reptiles in Colorado. CO Div. Wild. Publication Code DOW-M-I-3-86. 131.

Herrick, Jeffrey E., J.W. Van Zee, K.M. Haystad, L.M. Burkett, and W.G. Witford. 2005. Monitoring Manual for Grassland, Shrubland, and Savanna Ecosystems, Volume II. U.S. Dept. of Agriculture, Agricultural Research Service. Jornada Experimental Range, Las Cruces, N.M.

Kingery, H., Ed. (1998) Colorado Breeding Birds Atlas. Dist. CO Wildlife Heritage Foundation: Denver, CO. 636.

National Water & Climate Center. USDA-NRCS. USDA Pacific Northwest Climate Hub: Portland, OR. http://www.wcc.nrcs.usda.gov/ Accessed March 2016

National Weather Service Co-op Program. 2010. Colorado Climate Center. Colorado State Univ. Web. http://climate.atmos.colostate.edu/dataaccess.php March 2016

Pellant, M., P. Shaver, D.A. Pyke, J.E. Herrick. (2005) Interpreting Indicators of Rangeland Health, Version 4. BLM National Business Center Printed Materials Distribution Service: Denver, CO.

PLANTS Database. 2015. USDA-NRCS. Web. http://plants.usda.gov/java/ Accessed August 2015. February 2016

PRISM Climate Data. 2015. Prism Climate Group. Oregon State Univ. Corvallis, OR. http://www.prism.oregonstate.edu/ Accessed August 2015.

Rennicke, J. 1990. Colorado Wildlife. Falcon Press, Helena and Billings, MT and CO Div. Wildlife, Denver CO. 138.

Schoeneberger, P.J., D.A. Wysockie, E.C. Benham, and Soil Survey Staff. 2012. Field book for describing and sampling soils, Version 3.0. Natural Resources Conservation Service, National Soil Survey Center: Lincoln, NE.

The Denver Posse of Westerners. 1999. The Cherokee Trail: Bent’s Old Fort to Fort Bridger. The Denver Posse of Westerners, Inc. Johnson Printing: Boulder, CO

U.S. Dept. of Agriculture, Agricultural Research Service. September, 1991. Changes in Vegetation and Land Use I eastern Colorado, A Photographic study, 1904-1986.

U.S. Dept. of Agriculture, Natural Resources Conservation Service. 2006. Land Resource Regions and Major Land Resource areas of the United States, the Caribbean, and the Pacific Basin. US Department of Agriculture Handbook 296.

U.S. Dept. of Agriculture, Natural Resources Conservation Service. National Geospatial Center of Excellence. Colorado annual Precipitation Map from 1981-2010, Annual Average Precipitation by State

U.S. Dept. of Agriculture, Natural Resources Conservation Service. 2009. Part 630, Hydrology, National Engineering Handbook

U.S. Dept. of Agriculture, Natural Resources Conservation Service. 1972-2012. National Engineering Handbook Hydrology Chapters. http://www.nrcs.usda.gov/wps/portal/nrcs/detailfull/national/water/?&cid=stelprdb1043063 Accessed August 2015.

U.S. Dept. of Agriculture, Natural Resources Conservation Service. National Soil Survey Handbook title 430-VI. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/ref/?cid=nrcs142p2_054242 Accessed July 2015

U.S. Dept. of Agriculture, Soil Survey Division Staff. 1993. Soil Survey Manual.

U.S. Dept. of Agriculture.1973. Soil Survey of Baca County, Colorado.

U.S. Dept. of Agriculture. 1970. Soil Survey of Bent County, Colorado.

U.S. Dept. of Agriculture. 1968. Soil Survey of Crowley County, Colorado.

U.S. Dept. of Agriculture. 1981 Soil Survey of El Paso County Area, Colorado.

U.S. Dept. of Agriculture. 1995. Soil Survey of Fremont County Area, Colorado.

U.S. Dept. of Agriculture. 1983. Soil Survey of Huerfano County Area, Colorado.

U.S. Dept. of Agriculture.1981. Soil Survey of Kiowa County, Colorado.

Western Regional Climate Center. 2022. Climate of Colorado, climate of the eastern plains. https://wrcc.dri.edu/Climate/narrative_co.php (accessed 9 August 2022).

Contributors

Laura L. Craven MLRA Project Leader NRCS
Doug Whisenhunt Ecological Site Specialist NRCS
Kimberly A. Diller Ecological Site Specialist NRCS
Ben P. Berlinger Rangeland Management Specialist NRCS Retired

Approval

Kirt Walstad, 9/07/2023

Acknowledgments

Project Staff:
Kimberly Diller, Ecological Site Specialist, NRCS MLRA, Pueblo Soil Survey Office (SSO)
Laura Craven, MLRA 69 Soil Survey Leader, NRCS MLRA Pueblo SSO
Amber Wyndham, Soil Scientist, NRCS MLRA Pueblo SSO
Ben Berlinger, Rangeland Management Specialist, Ret. NRCS La Junta, CO

Program Support:
Rachel Murph, NRCS State Rangeland Management Specialist
David Kraft, NRCS MLRA Ecological Site Specialist-QA (acting), Emporia, KS
Chad Remley, Regional Director, N. Great Plains Soil Survey, Salina, KS
B.J. Shoup, State Soil Scientist, Denver
Eugene Backhaus, State Resource Conservationist, Denver
Chanda Garcia, NRCS State Biologist, NRCS, Denver CO
Patty Knupp, Area 3 Biologist, NRCS, Pueblo CO

Partners/Contributors:
James Kulbeth, Natural Resources Specialist, Department of the Army, Fort Carson, CO
John Lamman, Rangeland Management Specialist, BLM, Cañon City, CO
Steve Olson, Botanist, USFS, Pueblo, CO
Renee Rondeau, Ecologist, CO Natural Heritage Program, Hesperus, CO
Terri Schultz, The Nature Conservancy, Ft. Collins, CO
John Valentine, District Manager, CO State Land Board, Pueblo, CO

Those involved in developing earlier versions of this site description include: Ben Berlinger, rangeland management specialist (RMS); Scott Woodall, RMS; Lee Neve, soil scientist; Julie Elliott, RMS; Terri Skadeland, Colorado State biologist; and Herman Garcia, Colorado State RMS.

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)	Ben Berlinger, Daniel Nosal, Kimberly Diller
Contact for lead author	Ben Berlinger, Area Rangeland Management Specialist, La Junta, CO,
Date	01/12/2005
Approved by	Kirt Walstad
Approval date
Composition (Indicators 10 and 12) based on	Annual Production