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Ecological site R069XY021CO

Choppy Sands

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 Choppy Sands Ecological Site, LRUs A and B, was developed from an earlier version of the Choppy Sands Ecological Site (2004, revised in 2007). This earlier version of the Choppy Sands ESD (2004) was based on input from NRCS (formerly Soil Conservation Service) and historical information obtained from the Choppy Sands Range Site description (1975). 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 Choppy Sands Ecological Site occurs in an upland position, on slopes greater than 10 percent. The soil is sandy and at least 60 inches deep. depth There are many small ridges, sharp peaks, and terracettes giving it a rough or “choppy” appearance. Blowouts are present.

Associated sites

R069XY019CO	Deep Sand The Deep Sands Ecological Site is commonly adjacent to and interspersed with the Choppy Sands Ecological Site.
R069XY026CO	Sandy Plains The Sandy Plains Ecological Site is commonly adjacent to and interspersed with the Choppy Sands Ecological Site.

R069XY019CO

Deep Sand

The Deep Sands Ecological Site is commonly adjacent to and interspersed with the Choppy Sands Ecological Site.

R069XY026CO

Sandy Plains

The Sandy Plains Ecological Site is commonly adjacent to and interspersed with the Choppy Sands Ecological Site.

Similar sites

R069XY019CO	Deep Sand The Deep Sands Ecological Site is on stabilized dunes and normally does not have blowouts.
R069XY026CO	Sandy Plains The Sandy Plains Ecological Site is on slopes of less than 10 percent, has developed soil horizons, and includes fine sandy loam and sandy loam surface textures.

R069XY019CO

Deep Sand

The Deep Sands Ecological Site is on stabilized dunes and normally does not have blowouts.

R069XY026CO

Sandy Plains

The Sandy Plains Ecological Site is on slopes of less than 10 percent, has developed soil horizons, and includes fine sandy loam and sandy loam surface textures.

Table 1. Dominant plant species

Tree	Not specified
Shrub	(1) Prunus pumila var. besseyi (2) Amorpha canescens
Herbaceous	(1) Andropogon hallii (2) Calamovilfa longifolia

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Physiographic features

This site occurs on plains.

Table 2. Representative physiographic features

Landforms	(1) Hill (2) Ridge (3) Blowout
Runoff class	Low to very low
Flooding frequency	None
Ponding frequency	None
Elevation	1,128 – 1,859 m
Slope	5 – 25%
Ponding depth	0 cm
Water table depth	152 cm
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)	305-356 mm
Frost-free period (actual range)	121-135 days
Freeze-free period (actual range)	141-164 days
Precipitation total (actual range)	279-406 mm
Frost-free period (average)	129 days
Freeze-free period (average)	153 days
Precipitation total (average)	330 mm

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

Soil features

The soils of this site are very deep. They are excessively drained with very rapid permeability. The surface layer thickness ranges from 4 to 7 inches. The soil moisture regime is ustic aridic. The soil temperature regime is mesic.
Major soil series correlated to this ecological site include: Valent.

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 sands
Surface texture	(1) Sand
Family particle size	(1) Sandy
Drainage class	Excessively drained
Permeability class	Very rapid
Soil depth	152 – 203 cm
Surface fragment cover <=3"	0%
Surface fragment cover >3"	0%
Available water capacity (0-101.6cm)	4.06 – 8.13 cm
Calcium carbonate equivalent (0-101.6cm)	0 – 5%
Electrical conductivity (0-101.6cm)	0 – 2 mmhos/cm
Sodium adsorption ratio (0-101.6cm)	0 – 1
Soil reaction (1:1 water) (0-101.6cm)	6.6 – 7.8
Subsurface fragment volume <=3" (Depth not specified)	0 – 5%
Subsurface fragment volume >3" (Depth not specified)	0%

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.

This is a mixed tallgrass and midgrass prairie with a diverse forb and shrub component. Sand bluestem (warm-season, tall bunchgrass) and prairie sandreed (warm-season, tall rhizomatous grass) are primary. Secondary components include midgrasses, such as needle and thread and Indian ricegrass (cool-season bunchgrass) and little bluestem (warm-season bunch). Forbs, such as lemon scurfpea, are common. Shrubs include sand sagebrush and western sandcherry.

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).

Continuous grazing without adequate recovery opportunities following each grazing event during the growing season will initially cause blue grama, hairy grama, and small soapweed to increase. Species such as sand bluestem, prairie sandreed, switchgrass, western sandcherry, leadplant, and palatable forbs will decrease in frequency and production. Sandhill muhly will increase under continuous grazing and can become dominant. Non-use, continuous grazing, wildfire, brush management, or any type of physical disturbance can lead to serious erosion problems (blowouts, wind scoured areas) on these fragile soils.

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. Sandhill Muhly State

3. Eroded State

T1A	-	Heavy, season-long grazing. Lack of fire.
T1B	-	Non-use. Lack of fire.
R2A	-	Prescribed grazing. Prescribed fire.
T2A	-	Heavy, season-long grazing. Lack of fire.
R3A	-	Prescribed grazing. Prescribed fire.

State 1 submodel, plant communities

1.1. Andropogon hallii-Calamovilfa longifolia, (sand bluestem-prairie sandreed)

1.2. Bouteloua gracilis-Bouteloua hirsuta, (blue grama-hairy grama)

1.3. Andropogon hallii-Calamovilfa longifolia, (sand bluestem-prairie sandreed) Low Plant Density, Excessive Litter Plant Community

1.1A	-	Heavy, season-long grazing. Lack of fire.
1.1B	-	Non-use. Lack of fire.
1.2A	-	Prescribed grazing. Prescribed burning.
1.3A	-	Prescribed grazing. Prescribed fire.

State 2 submodel, plant communities

2.1. Muhlenbergia pungens (Sandhill muhly)

State 3 submodel, plant communities

3.1. Bromus tectorum-Cenchrus (spp.), (cheatgrass-sandbur)

3.2. Redfieldia flexuosa-Achnatherum hymenoides, (blowout grass-indian ricegrass).

3.1A	-	Prescribed grazing. Prescribed fire.
3.2A	-	Heavy, season-long grazing. Lack of fire.

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 (Guyette and others), and grazing by large ungulates with adequate recovery periods. High production of perennial grasses and extensive soil cover allow for increased soil moisture retention, vegetative production, and overall soil quality.

Dominant plant species

western sandcherry (Prunus pumila var. besseyi), shrub
leadplant (Amorpha canescens), shrub
sand sagebrush (Artemisia filifolia), shrub
sand bluestem (Andropogon hallii), grass
prairie sandreed (Calamovilfa longifolia), grass

Community 1.1
Andropogon hallii-Calamovilfa longifolia, (sand bluestem-prairie sandreed)

This is the interpretive plant community and is considered to be the reference plant community. This plant community evolved with grazing by large herbivores, is well suited for grazing by domestic livestock and is in areas that are properly managed with grazing that allows adequate recovery periods following each grazing occurrence during the growing season. The plant community consists chiefly of tall warm-season grasses. Principle dominants are sand bluestem, prairie sandreed, needle and thread, and little bluestem. Sub-dominant grasses include blue grama, hairy grama, switchgrass, and Indiangrass. Important forbs and shrubs include lemon scurfpea, silky prairie clover, bigtop dalea, leadplant, and sandcherry. The potential vegetation is about 70 to 85 percent grasses and grass-like plants, 10 to 15 percent forbs and 5 to 15 percent woody plants. Prescribed grazing that allows for adequate recovery periods after each grazing event and proper stocking will maintain this plant community. Continual or repeated spring grazing and summer deferment will reduce the cool-season component of this plant community and increase the warm-season component. Spring deferment and continual summer grazing will increase the cool-season component and decrease the warm-season component. This community is resistant to many disturbances except repeated heavy, seasonal herbivory without adequate recovery opportunity, plowing, and development into urban or other uses. Plant litter is properly distributed with very little movement off-site and natural plant mortality is very low. Nutrient cycle, water cycle, energy flow, and community dynamics are all functioning and intact. Extensive and diverse rooting systems are present. Carbon sequestration above and below ground is excellent. If continually grazed or over stocked to the point of leaving little stubble or litter, wind erosion will become a major concern. Production in this community can vary from 600 to 1400 pounds of air-dry vegetation per acre per year depending on the weather and averages 1150 pounds.

Dominant plant species

western sandcherry (Prunus pumila var. besseyi), shrub
leadplant (Amorpha canescens), shrub
sand sagebrush (Artemisia filifolia), shrub
sand bluestem (Andropogon hallii), grass
prairie sandreed (Calamovilfa longifolia), grass

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

Table 5. Annual production by plant type

Plant type	Low (kg/hectare)	Representative value (kg/hectare)	High (kg/hectare)
Grass/Grasslike	488	998	1177
Forb	123	163	196
Shrub/Vine	62	129	196
Total	673	1290	1569

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-Bouteloua hirsuta, (blue grama-hairy grama)

This plant community evolves with heavy, continuous grazing without adequate recovery periods during the growing seaso. Sand bluestem, yellow Indiangrass, switchgrass, prairie sandreed, purple prairieclover, western sandcherry, and leadplant have decreased but are still present in small amounts. Blue grama, hairy grama, needleandthread, and small soapweed have increased and dominate the community. Sand dropseed, red threeawn, sandhill muhly, lemon scurfpea, hairy goldaster, croton, Cuman ragweed, tenpetal blazingstar, and groundplum milkvetch have also increased. This plant community is relatively stable but at risk of losing key tall grass species, palatable forbs, western sandcherry, and leadplant. The nutrient cycle, water cycle, and energy flow have been impaired due to reduced production, a shift in root structure, and species composition. Less litter is being produced. Small blowouts or wind scoured areas can be forming at this stage. Production can vary from 300 to 750 pounds of air-dry vegetation per acre per year and averages 550 pounds.

Dominant plant species

sand sagebrush (Artemisia filifolia), shrub
soapweed yucca (Yucca glauca), shrub
blue grama (Bouteloua gracilis), grass
hairy grama (Bouteloua hirsuta), grass
needle and thread (Hesperostipa comata ssp. comata), 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
Andropogon hallii-Calamovilfa longifolia, (sand bluestem-prairie sandreed) Low Plant Density, Excessive Litter Plant Community

This plant community results from a lack of grazing for long periods of time in the absence of fire. Plant composition is similar to the reference plant community. In time, however, individual species production and frequency lowers. Much of the nutrients are tied up in excessive litter. The semiarid environment and the absence of animal traffic to break down litter slows nutrient cycling. Aboveground litter also limits sunlight from reaching plant crowns. Many plants, especially bunchgrasses, die off. Thick litter and absence of grazing or fire reduce seed germination and establishment. This plant community changes rapidly with prescribed grazing which allows animal impact and adequate recovery periods between grazing events. Production can vary from 150 to 1100 pounds of air-dry vegetation per acre per year.

Dominant plant species

western sandcherry (Prunus pumila var. besseyi), shrub
leadplant (Amorpha canescens), shrub
sand sagebrush (Artemisia filifolia), shrub
sand bluestem (Andropogon hallii), grass
prairie sandreed (Calamovilfa longifolia), 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

Recurring, heavy growing season herbivory without adequate recovery opportunity moves this plant community toward the 1.2 community. Lack of fire accelerates the process. Reduced production and erosion are a concern.

Pathway 1.1B
Community 1.1 to 1.3

Non-use and lack of fire shift this plant community to the Low Plant Density, Excessive Litter Plant Community.

Pathway 1.2A
Community 1.2 to 1.1

Prescribed grazing that allows for adequate recovery periods following each grazing event and prescribed fire move this plant community to the reference plant community.

Conservation practices

Prescribed Burning
Prescribed Grazing

Pathway 1.3A
Community 1.3 to 1.1

Grazing that allows for adequate recovery opportunity following each grazing event can shift this plant community toward the reference plant community. Prescribed fire accelerates this process.

Conservation practices

Prescribed Burning
Prescribed Grazing

State 2
Sandhill Muhly State

This state is dominated by Sandhill muhly, and results from continuous, heavy grazing without adequate recovery opportunity between grazing events, and lack of fire. The state is characterized by a lack of resiliency and resistance to disturbances. Biological integrity, site stability, and hydrologic function are greatly reduced.

Dominant plant species

sand sagebrush (Artemisia filifolia), shrub
soapweed yucca (Yucca glauca), shrub
sandhill muhly (Muhlenbergia pungens), grass
Fendler threeawn (Aristida purpurea var. longiseta), grass
blowout grass (Redfieldia flexuosa), grass

Community 2.1
Muhlenbergia pungens (Sandhill muhly)

This plant community established under historic, continuous grazing. Sandhill muhly has increased to the point of being the dominant species. Sand dropseed, red threeawn, blowout grass, and lemon scurfpea have also increased. Needle and thread, Indian ricegrass, and little bluestem have decreased to remnant amounts. Sand bluestem, Indiangrass, switchgrass, prairie sandreed, western sandcherry, and leadplant are absent from the community. Species diversity and overall production are reduced significantly. Litter levels are low. Bare ground has increased and blowouts are forming or enlarging. Carbon reserves have been severely depleted. Community dynamics, nutrient cycle, water cycle, and energy flow have been severely impaired. Production varies from 100 to 350 pounds of air-dry vegetation per acre per year and averages 250 pounds.

Dominant plant species

sandhill muhly (Muhlenbergia pungens), 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

This state results from continued disturbances that further impair the stability of the site. Continuous, heavy grazing without providing adequate recovery opportunity following grazing events is the driver of the process. Blowouts can develop.

Dominant plant species

sand sagebrush (Artemisia filifolia), shrub
soapweed yucca (Yucca glauca), shrub
cheatgrass (Bromus tectorum), grass
sandbur (Cenchrus), grass
sixweeks fescue (Vulpia octoflora), grass

Community 3.1
Bromus tectorum-Cenchrus (spp.), (cheatgrass-sandbur)

This early succession plant community can either be the result of continuous, heavy grazing applied to an early perennial plant community, or the result of controlled short-term animal impact and prescribed grazing applied to a blowout. Production can vary greatly depending on the plant density and weather conditions in any year. Cheatgrass, Japanese brome, kochia, Russian thistle, sunflower, pigweed, sandbur, sixweeks fescue, and annual buckwheat are common. Wind erosion is a concern. Production can vary from 0 to 200 pounds per acre of air-dry vegetation per year.

Dominant plant species

sand sagebrush (Artemisia filifolia), shrub
soapweed yucca (Yucca glauca), shrub
cheatgrass (Bromus tectorum), grass
sandbur (Cenchrus), grass
sixweeks fescue (Vulpia octoflora), grass
Russian thistle (Salsola), other herbaceous
pigweed (Amaranthus), other herbaceous

Community 3.2
Redfieldia flexuosa-Achnatherum hymenoides, (blowout grass-indian ricegrass).

This plant community evolves with long term heavy, continuous grazing from a more advanced plant community, or with prescribed grazing from the 3.1 community. Blowout grass, Indian ricegrass, sandhill muhly, needle and thread, and lemon scurfpea are some of the first perennials to occupy this community. Wind erosion remains a concern. Production can vary from 50 to 200 pounds per acre of air-dry vegetation per year.

Dominant plant species

sand sagebrush (Artemisia filifolia), shrub
soapweed yucca (Yucca glauca), shrub
blowout grass (Redfieldia flexuosa), grass
Indian ricegrass (Achnatherum hymenoides), grass

Pathway 3.1A
Community 3.1 to 3.2

Prescribed grazing that allows adequate recovery opportunity between grazing events moves this plant community toward the 3.2 community. Prescribed fire will accelerate this transition.

Conservation practices

Prescribed Burning
Prescribed Grazing

Pathway 3.2A
Community 3.2 to 3.1

Continuous, heavy grazing without adequate recovery opportunity between grazing events moves this plant community toward the 3.1 community. Lack of fire accelerates this transition. Eventually blowouts can result.

Transition T1A
State 1 to 2

Repeated, heavy season-long grazing without adequate recovery opportunity between grazing events and lack of fire shift this plant community across an ecological threshold to the Sandhill Muhly State. Decreased production and increased erosion are concerns.

Transition T1B
State 1 to 3

Non-use of greater than 25 years and lack of fire can move this plant community across an ecological threshold causing accelerated erosion. Annuals or early perennial plant communities can result depending on the amount of non-use or rest involved with the transition. Blowouts can occur.

Restoration pathway R2A
State 2 to 1

Long-term prescribed grazing moves this state to the Reference State. This transition may take greater than 25 years depending on the size of the area, proximity to seed source and remnant species present. Prescribed fire will accelerate this process.

Conservation practices

Prescribed Burning
Prescribed Grazing

Transition T2A
State 2 to 3

Continuous, heavy grazing without an adequate recovery period will cause this state to cross an ecological threshold to the Eroded State. Lack of fire can accelerate this transition. Blowouts can result, and severe erosion is a major concern.

Restoration pathway R3A
State 3 to 1

Long-term prescribed grazing that allows an adequate recovery period can eventually move this plant community toward the Reference State. Prescribed fire can accelerate this recovery.

Conservation practices

Prescribed Burning
Prescribed Grazing

Additional community tables

Table 6. Community 1.1 plant community composition

Group	Common name	Symbol	Scientific name	Annual production (kg/hectare)	Foliar cover (%)
Grass/Grasslike
1				902–1098
	sand bluestem	ANHA	Andropogon hallii	258–325	–
	prairie sandreed	CALO	Calamovilfa longifolia	191–258	–
	switchgrass	PAVI2	Panicum virgatum	67–191	–
	needle and thread	HECOC8	Hesperostipa comata ssp. comata	67–129	–
	little bluestem	SCSC	Schizachyrium scoparium	39–90	–
	Indiangrass	SONU2	Sorghastrum nutans	39–67	–
	sand dropseed	SPCR	Sporobolus cryptandrus	11–67	–
	blue grama	BOGR2	Bouteloua gracilis	11–67	–
	Grass, perennial	2GP	Grass, perennial	11–67	–
	hairy grama	BOHI2	Bouteloua hirsuta	11–39	–
	blowout grass	REFL	Redfieldia flexuosa	11–39	–
	Schweinitz's flatsedge	CYSC3	Cyperus schweinitzii	0–28	–
	sideoats grama	BOCU	Bouteloua curtipendula	0–28	–
	sun sedge	CAINH2	Carex inops ssp. heliophila	11–28	–
	prairie Junegrass	KOMA	Koeleria macrantha	0–28	–
	sandhill muhly	MUPU2	Muhlenbergia pungens	11–28	–
	thin paspalum	PASE5	Paspalum setaceum	0–28	–
	Indian ricegrass	ACHY	Achnatherum hymenoides	11–28	–
	Fendler threeawn	ARPUL	Aristida purpurea var. longiseta	0–11	–
	needleleaf sedge	CADU6	Carex duriuscula	0–11	–
Forb
2				129–196
	lemon scurfpea	PSLA3	Psoralidium lanceolatum	11–39	–
	Forb, perennial	2FP	Forb, perennial	11–39	–
	silky prairie clover	DAVI	Dalea villosa	11–28	–
	annual buckwheat	ERAN4	Eriogonum annuum	11–28	–
	shaggy dwarf morning-glory	EVNU	Evolvulus nuttallianus	0–28	–
	phlox heliotrope	HECO5	Heliotropium convolvulaceum	0–11	–
	stiff sunflower	HEPAP2	Helianthus pauciflorus ssp. pauciflorus	0–11	–
	hairy false goldenaster	HEVI4	Heterotheca villosa	0–11	–
	bush morning-glory	IPLE	Ipomoea leptophylla	0–11	–
	flaxflowered ipomopsis	IPLOL	Ipomopsis longiflora ssp. longiflora	0–11	–
	dotted blazing star	LIPU	Liatris punctata	0–11	–
	lacy tansyaster	MAPIP4	Machaeranthera pinnatifida ssp. pinnatifida var. pinnatifida	0–11	–
	tenpetal blazingstar	MEDE2	Mentzelia decapetala	0–11	–
	broadbeard beardtongue	PEAN4	Penstemon angustifolius	0–11	–
	woolly plantain	PLPA2	Plantago patagonica	0–11	–
	snowball sand verbena	ABFR2	Abronia fragrans	0–11	–
	Cuman ragweed	AMPS	Ambrosia psilostachya	0–11	–
	tarragon	ARDR4	Artemisia dracunculus	0–11	–
	groundplum milkvetch	ASCR2	Astragalus crassicarpus	0–11	–
	Texas croton	CRTE4	Croton texensis	0–11	–
	nineanther prairie clover	DAEN	Dalea enneandra	0–11	–
	purple prairie clover	DAPUP	Dalea purpurea var. purpurea	0–11	–
	upright prairie coneflower	RACO3	Ratibida columnifera	0–11	–
	veiny dock	RUVE2	Rumex venosus	0–11	–
	Missouri goldenrod	SOMI2	Solidago missouriensis	0–11	–
	prairie spiderwort	TROC	Tradescantia occidentalis	0–11	–
Shrub/Vine
3				67–196
	western sandcherry	PRPUB	Prunus pumila var. besseyi	22–67	–
	Shrub (>.5m)	2SHRUB	Shrub (>.5m)	11–39	–
	leadplant	AMCA6	Amorpha canescens	11–39	–
	sand sagebrush	ARFI2	Artemisia filifolia	11–39	–
	soapweed yucca	YUGL	Yucca glauca	11–28	–
	skunkbush sumac	RHTR	Rhus trilobata	0–11	–
	prairie rose	ROAR3	Rosa arkansana	0–11	–
	spreading buckwheat	EREF	Eriogonum effusum	0–11	–
	spinystar	ESVIV	Escobaria vivipara var. vivipara	0–11	–
	brittle pricklypear	OPFR	Opuntia fragilis	0–11	–
	plains pricklypear	OPPO	Opuntia polyacantha	0–11	–

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 grasses, forbs, and shrubs in this plant community provide habitat for reptiles such as western rattlesnake and bullsnake. The structural diversity in the plant community on this site provides habitat for Cassin’s and Brewer’s sparrow, lark bunting, scaled quail, and ferruginous and Swainson’s hawks. The combination of mid-tall grasses and shrubs provides habitat for lesser prairie chicken in the eastern part of this ecological site. Small mammals, such as white-tailed jackrabbit, badger, swift fox, and several species of mice, are common in this plant community. Pronghorn is a typical ungulate in this community.

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

Communities 1.3-2.1-3.1:
As these communities develop into an open landscape the wildlife species shift away from reference plant community species and toward the wildlife species that prefer unvegetated areas and short plants. Texas short- lizard, six-lined racerunner, and black-tailed jackrabbit would be expected more frequently.

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.

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

Reference Plant Community - (1150) (0.32)

Community 1.2 - (550) (0.15)

Community 2.1 - (250) (0.07)

All stocking rates are guidelines and on- site investigation is needed before developing actual grazing plans.

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 and runoff potential for this site ranges from high to moderate. Water transmission through group A soils is normally greater than 0.30 inches per hour. Runoff is expected to occur only during the most intense storms (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

No appreciable wood products are present on the site.

Other products

Site Development & 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 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. These will need review for future updates at the next Approved level. Minor edit has been made to Species Comp List.

Each Alternative State/Community:

Complete to Provisional level. Narrative for each state/community has been updated.

Supporting Information (Site Interpretations, Assoc. & Similar Sites, Inventory Data References, Agency/State Correlation, References):

Updated. All “Required” items are complete to Provisional level.

Supporting Information: Only one Inventory Data Reference located (NRI). More field data collection is needed to support this site concept.

- There is minimal NRI data (2004-2015) and no archived 417 data for Choppy Sands site. Need to collect Medium/High Intensity site data to support this site.

Animal Community
Wildlife Interpretations:
- First “overview” paragraph was retained. Individual Plant Community phase interpretations have been 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 Interpretations:
- Recreational Uses, Wood Products, Other Products, and Plant Preferences table, are carried over from “previously Approved” ESD (2004).

Rangeland Health Reference Sheet:

- From “Previously Approved” ESD (2004). This needs to be updated at the next “Approved” level.

Note: Choppy Sands ESD is not in LRU C.

“Future work, as described in a project plan, to validate the information in this provisional ecological site description is needed. This will include field activities to collect low and medium intensity sampling, soil correlations, and analysis of that data. Annual field reviews should be done by soil scientists and vegetation specialists. A final field review, peer review, quality control, and quality assurance reviews of the ESD will be needed to produce the final document.” (NI 430_306 ESI and ESD, April, 2015)

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, percent 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

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

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, CO 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, Kimberly Diller, Daniel Nosal
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