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Ecological site R069XY080CO

Gypsum Breaks

Last updated: 9/07/2023
Accessed: 04/26/2024

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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 (USFS). 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 Gypsum Breaks Ecological Site, LRUs A & B, was developed from an earlier version of the Gypsum Breaks Ecological Site (2004, revised in 2007). This earlier version of the Gypsum Breaks Ecological Site (2004) was based on input from Natural Resources Conservation Service (formerly Soil Conservation Service) and historical information obtained from the Gypsum Breaks Range Site descriptions. 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 Gypsum Breaks Ecological Site is a run-off site on slopes of greater than 10 percent. The soil depth is less than 20 inches over gypsum bedrock.

Associated sites

R069XY006CO	Loamy Plains This ecological site is commonly adjacent.
R069XY053CO	Sandstone Breaks This ecological site is commonly adjacent.

R069XY006CO

Loamy Plains

This ecological site is commonly adjacent.

R069XY053CO

Sandstone Breaks

This ecological site is commonly adjacent.

Similar sites

R069XY048CO	Shale Breaks This ecological site is over shale bedrock.
R069XY058CO	Limestone Breaks This ecological site is over limestone bedrock.
R069XY053CO	Sandstone Breaks This ecological site is over sandstone bedrock.

R069XY048CO

Shale Breaks

This ecological site is over shale bedrock.

R069XY058CO

Limestone Breaks

This ecological site is over limestone bedrock.

R069XY053CO

Sandstone Breaks

This ecological site is over sandstone bedrock.

Table 1. Dominant plant species

Tree	(1) Juniperus monosperma
Shrub	(1) Artemisia bigelovii (2) Krascheninnikovia lanata
Herbaceous	(1) Bouteloua eriopoda (2) Pleuraphis jamesii

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Physiographic features

This site occurs on plains or canyonlands.

Table 2. Representative physiographic features

Landforms	(1) Hill (2) Ridge (3) Pediment
Runoff class	Very high
Flooding frequency	None
Ponding frequency	None
Elevation	3,700 – 6,400 ft
Slope	1 – 30%
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) EADS [USC00052446], Eads, CO
(2) PUEBLO RSVR [USC00056765], Pueblo, CO
(3) LA JUNTA 20 S [USC00054726], La Junta, CO
(4) TACONY 13 SE [USC00058157], Boone, CO
(5) CHERAW 1 N [USC00051539], La Junta, CO
(6) ORDWAY 21 N [USC00056136], Ordway, CO
(7) ROCKY FORD 2 SE [USC00057167], Rocky Ford, CO
(8) PUEBLO MEM AP [USW00093058], Pueblo, CO
(9) ORDWAY 2 ENE [USC00056131], Ordway, CO

Soil features

The soils of this site are very shallow or shallow. They are well drained with moderate slow or moderate permeability. The surface layer thickness ranges from 2 to 5 inches. The soil moisture regime is ustic aridic. The soil temperature regime is mesic. Parent material kind is slope alluvium over residuum weathered from gypsum and shale. Parent material originated from shale.

Major soil series correlated to this ecological site include Ovmesa and Shingle variant.

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) Slope alluvium – shale
Surface texture	(1) Loam
Family particle size	(1) Loamy
Drainage class	Well drained
Permeability class	Moderately slow to moderate
Soil depth	9 – 20 in
Surface fragment cover <=3"	6%
Surface fragment cover >3"	Not specified
Available water capacity (0-20in)	2.4 – 4 in
Calcium carbonate equivalent (0-20in)	1 – 14%
Electrical conductivity (0-20in)	9 – 20 mmhos/cm
Sodium adsorption ratio (0-20in)	1 – 10
Soil reaction (1:1 water) (0-20in)	7.4 – 8.4
Subsurface fragment volume <=3" (Depth not specified)	14%
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 short warm-season stoloniferous grass (black grama), mid warm-season rhizomatous grass (galleta), mid warm-season bunchgrass (little bluestem, sideoats grama, Nealley dropseed), and short warm-season bunchgrass (blue and hairy grama). Mid cool-season bunchgrass (New Mexico feathergrass, Indian ricegrass, needle and thread) and mid- cool-season rhizomatous grass (western wheatgrass) are secondary. Minor grasses include mid- warm-season bunchgrass (alkali sacaton, sand dropseed), short warm-season bunchgrass (purple threeawn, ring muhly), and short cool-season bunchgrass (bottlebrush squirreltail). Various shrubs (Bigelow sagebrush, fourwing saltbush, winterfat) and forbs (dotted gayfeather, scarlet globemallow, James’ cryptantha) also occur on the site. Trees such as oneseed juniper are present in minor amounts.

Recurring heavy, seasonal herbivory without adequate recovery periods causes black grama to decrease along with mid- warm-season grasses and winterfat. Bigelow sagebrush increases. Grasses such as little bluestem, sideoats grama, New Mexico feathergrass, western wheatgrass, and needle and thread decrease in both frequency and production. Blue grama, galleta, Nealley dropseed, hairy grama, and galleta increase. Forbs and shrubs such as purple prairie clover, American vetch, and fourwing saltbush decrease. Continuous, heavy grazing causes this site to continue to deteriorate. Black grama persists in trace amounts in areas inaccessible to grazing. Mid- and tallgrasses can eventually be removed from the plant community. Over the long-term, continuous use will result in large amounts of bare ground. Species such as Fendler's threeawn, sand dropseed, small soapweed, and broom snakeweed increase on the site. Mat loco, sessile nailwort, and annuals also increase. Annual weeds such as burningbush and Russian thistle may invade.

Drier and warmer climatic conditions exist in the central portion of MLRA 69 (LRU A). 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) will be higher in LRU A and total annual production will typically be 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/.

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.

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. Eroded State

T1A	-	Heavy, continuous grazing. Lack of fire.

State 1 submodel, plant communities

1.1. Bouteloua eriopoda-Pleuraphis jamesii (black grama-galleta).

1.2. Pleuraphis jamesii-Sporobolus nealleyi (gallata-gyp dropseed).

1.1A	-	Heavy, season-long grazing. Lack of fire.
1.2A	-	Prescribed grazing. Prescribed fire.

State 2 submodel, plant communities

2.1. Artemisia bigelovii - Yucca glauca/Bromus tectorum - Vulpia octoflora (Bigelow sage - yucca/cheatgrass - sixweeks feascue).

State 1
Reference State

The Reference State is characterized by two plant community phases that represent the natural range of variability and disturbance regimes within the site. These plant community 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.

Dominant plant species

oneseed juniper (Juniperus monosperma), tree
Bigelow sage (Artemisia bigelovii), shrub
winterfat (Krascheninnikovia lanata), shrub
fourwing saltbush (Atriplex canescens), shrub
black grama (Bouteloua eriopoda), grass
James' galleta (Pleuraphis jamesii), grass
blue grama (Bouteloua gracilis), grass

Community 1.1
Bouteloua eriopoda-Pleuraphis jamesii (black grama-galleta).

This plant community is the interpretive plant community for this site and is considered to be the reference plant community. This community evolved with grazing by large herbivores and is suited to grazing by domestic livestock. Historically, fires occurred infrequently. This plant community can be found on areas that are grazed and where the grazed plants receive adequate recovery periods during the growing season. The potential vegetation is about 70 to 85 percent grasses and grass-likes, 5 to 10 percent forbs, and 10 to 20 percent woody plants. The principal short and mid-grasses are black grama, galleta, little bluestem, sideoats grama, New Mexico feathergrass, and western wheatgrass. Secondary grasses include blue grama, needle and thread, and gyp dropseed. Sun sedge is common. Dominant forbs are dotted gayfeather, leafy false goldenweed, James' cryptantha, and scarlet globemallow. Bigelow sagebrush, winterfat, fourwing saltbush, and skunkbush sumac are some of the major shrubs found on this plant community. Oneseed juniper can occasionally be found on the site. This is a sustainable plant community in terms of soil stability, watershed function, and biological integrity. Litter is properly distributed where vegetative cover is continuous. Some litter movement may occur on steeper slopes. Decadence and natural plant mortality are very low. Community dynamics, nutrient cycle, water cycle, and energy flow are functioning properly. This community is resistant to most disturbances with the exceptions of heavy, continuous grazing, tillage, and development into urban or other uses. Areas having lost all vegetation, such as livestock and vehicle trails are subject to high erosion rates and extreme runoff. Total annual production, during an average year, ranges from 150 to 500 pounds of air-dry weight and averages 300 pounds.

Dominant plant species

oneseed juniper (Juniperus monosperma), tree
Bigelow sage (Artemisia bigelovii), shrub
fourwing saltbush (Atriplex canescens), shrub
winterfat (Krascheninnikovia lanata), shrub
black grama (Bouteloua eriopoda), grass
James' galleta (Pleuraphis jamesii), grass
blue grama (Bouteloua gracilis), 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	115	230	395
Shrub/Vine	25	45	65
Forb	10	23	35
Tree	0	2	5
Total	150	300	500

Figure 9. Plant community growth curve (percent production by month). CO6903, Warm-season dominant, cool-season sub-dominant; MLRA-69; upland fine 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	15	35	25	15	5	0	0	0

Community 1.2
Pleuraphis jamesii-Sporobolus nealleyi (gallata-gyp dropseed).

This plant community developed with heavy, season-long grazing and lack of fire. The dominant grasses are Gyp dropseed and galleta. Black grama, New Mexico feathergrass, little bluestem, and sideoats grama are still present as secondary grasses in the community. Alkali sacaton, Indian ricegrass, needle and thread, western wheatgrass, American vetch, winterfat, and fourwing saltbush have been reduced. Sand dropseed, Fendler's threeawn, Hood’s phlox, hairy goldaster, Cuman ragweed, and slimflower scurfpea have increased. Woody plants that have increased include small soapweed and broom snakeweed. Plant frequency and vigor have decreased. Reduction of mid- rhizomatous wheatgrass, nitrogen-fixing forbs, the shrub component, and increased warm-season short-grasses has begun to alter the biotic integrity of this community. Water and nutrient cycles are becoming impaired. Litter levels have been reduced. Flow paths and rills are more apparent. Pedestalled plants are common. Total annual production, during an average year, ranges from 75 to 250 pounds of air-dry weight and averages 150 pounds.

Dominant plant species

oneseed juniper (Juniperus monosperma), tree
Bigelow sage (Artemisia bigelovii), shrub
soapweed yucca (Yucca glauca), shrub
shadscale saltbush (Atriplex confertifolia), shrub
plains pricklypear (Opuntia polyacantha), shrub
James' galleta (Pleuraphis jamesii), grass
gyp dropseed (Sporobolus nealleyi), grass

Figure 10. Plant community growth curve (percent production by month). CO6904, Warm-season dominant; MLRA-69; upland fine 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	0	15	45	25	15	0	0	0	0

Pathway 1.1A
Community 1.1 to 1.2

Recurring seasonal herbivory without adequate recovery periods and lack of fire shift this plant community to the 1.2 community.

Pathway 1.2A
Community 1.2 to 1.1

Herbivory with adequate recovery opportunity between grazing, animal forage balance, and prescribed fire move this community to the reference community.

Conservation practices

Cover Crop
Prescribed Grazing

State 2
Eroded State

This state is represented by one community. The more palatable species have been replaced by less palatable species. Bare ground has increased and erosion potential is high. Soil loss can be severe. The Eroded State lacks stability, diversity, and productivity and is characterized by an impairment of all ecological functions.

Dominant plant species

oneseed juniper (Juniperus monosperma), tree
plains pricklypear (Opuntia polyacantha), shrub
shadscale saltbush (Atriplex confertifolia), shrub
soapweed yucca (Yucca glauca), shrub
cheatgrass (Bromus tectorum), grass
sixweeks fescue (Vulpia octoflora), grass
little barley (Hordeum pusillum), grass
Russian thistle (Salsola), other herbaceous
burningbush (Bassia scoparia), other herbaceous

Community 2.1
Artemisia bigelovii - Yucca glauca/Bromus tectorum - Vulpia octoflora (Bigelow sage - yucca/cheatgrass - sixweeks feascue).

Remnant amounts of grama grasses, little bluestem, western wheatgrass and shrubs such as winterfat and fourwing saltbush have been replaced by shadscale, broom snakeweed, plains pricklypear and plains greasebush. Bigelow sagebrush remains the dominant shrub on this plant community. Annual increasers and invaders include annual barley, sixweeks fescue, kochia, Russian thistle and cheatgrass. Total annual production, during an average year, ranges from 25 to 100 pounds per acre air-dry weight.

Dominant plant species

oneseed juniper (Juniperus monosperma), tree
Bigelow sage (Artemisia bigelovii), shrub
soapweed yucca (Yucca glauca), shrub
cheatgrass (Bromus tectorum), grass
sixweeks fescue (Vulpia octoflora), grass

Figure 11. Plant community growth curve (percent production by month). CO6904, Warm-season dominant; MLRA-69; upland fine 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	0	15	45	25	15	0	0	0	0

Transition T1A
State 1 to 2

Heavy, continuous grazing without adequate recovery periods between grazing events and lack of fire shift this state 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				210–255
	black grama	BOER4	Bouteloua eriopoda	45–60	–
	blue grama	BOGR2	Bouteloua gracilis	15–45	–
	James' galleta	PLJA	Pleuraphis jamesii	30–45	–
	New Mexico feathergrass	HENE5	Hesperostipa neomexicana	20–35	–
	little bluestem	SCSC	Schizachyrium scoparium	15–30	–
	western wheatgrass	PASM	Pascopyrum smithii	15–30	–
	sideoats grama	BOCU	Bouteloua curtipendula	10–25	–
	gyp dropseed	SPNE	Sporobolus nealleyi	10–20	–
	Grass, perennial	2GP	Grass, perennial	3–15	–
	alkali sacaton	SPAI	Sporobolus airoides	0–10	–
	sand dropseed	SPCR	Sporobolus cryptandrus	3–10	–
	needle and thread	HECOC8	Hesperostipa comata ssp. comata	0–5	–
	little barley	HOPU	Hordeum pusillum	0–5	–
	Indian ricegrass	ACHY	Achnatherum hymenoides	0–5	–
	Fendler threeawn	ARPUL	Aristida purpurea var. longiseta	3–5	–
	hairy grama	BOHI2	Bouteloua hirsuta	3–5	–
	sun sedge	CAINH2	Carex inops ssp. heliophila	3–5	–
	sixweeks fescue	VUOC	Vulpia octoflora	0–5	–
	squirreltail	ELELE	Elymus elymoides ssp. elymoides	0–3	–
	ring muhly	MUTO2	Muhlenbergia torreyi	0–3	–
Forb
2				15–30
	Forb, perennial	2FP	Forb, perennial	3–15	–
	dotted blazing star	LIPU	Liatris punctata	3–10	–
	James' cryptantha	CRCIJ	Cryptantha cinerea var. jamesii	3–5	–
	sulphur-flower buckwheat	ERUM	Eriogonum umbellatum	0–5	–
	leafy false goldenweed	OOFOF	Oonopsis foliosa var. foliosa	3–5	–
	scarlet globemallow	SPCO	Sphaeralcea coccinea	3–5	–
	desert princesplume	STPIP	Stanleya pinnata var. pinnata	0–3	–
	white heath aster	SYER	Symphyotrichum ericoides	0–3	–
	American vetch	VIAM	Vicia americana	0–3	–
	Rocky Mountain zinnia	ZIGR	Zinnia grandiflora	0–3	–
	creeping nailwort	PASE	Paronychia sessiliflora	0–3	–
	beardtongue	PENST	Penstemon	0–3	–
	slimflower scurfpea	PSTE5	Psoralidium tenuiflorum	0–3	–
	scarlet beeblossom	GACO5	Gaura coccinea	0–3	–
	hairy false goldenaster	HEVI4	Heterotheca villosa	0–3	–
	nineanther prairie clover	DAEN	Dalea enneandra	0–3	–
	purple prairie clover	DAPUP	Dalea purpurea var. purpurea	0–3	–
	Cuman ragweed	AMPS	Ambrosia psilostachya	0–3	–
	white sagebrush	ARLU	Artemisia ludoviciana	0–3	–
	twogrooved milkvetch	ASBI2	Astragalus bisulcatus	0–3	–
	groundplum milkvetch	ASCR2	Astragalus crassicarpus	0–3	–
	spiny milkvetch	ASKE	Astragalus kentrophyta	0–3	–
	plains blackfoot	MELE2	Melampodium leucanthum	0–3	–
Shrub/Vine
3				30–60
	Bigelow sage	ARBI3	Artemisia bigelovii	15–30	–
	fourwing saltbush	ATCA2	Atriplex canescens	3–15	–
	Shrub (>.5m)	2SHRUB	Shrub (>.5m)	3–15	–
	winterfat	KRLA2	Krascheninnikovia lanata	5–15	–
	plains pricklypear	OPPO	Opuntia polyacantha	0–5	–
	shadscale saltbush	ATCO	Atriplex confertifolia	0–5	–
	soapweed yucca	YUGL	Yucca glauca	0–5	–
	rubber rabbitbrush	ERNAG	Ericameria nauseosa ssp. nauseosa var. glabrata	0–3	–
	spinystar	ESVIV	Escobaria vivipara var. vivipara	0–3	–
	broom snakeweed	GUSA2	Gutierrezia sarothrae	0–3	–
	skunkbush sumac	RHTR	Rhus trilobata	0–3	–
Tree
4				0–3
	oneseed juniper	JUMO	Juniperus monosperma	0–3	–

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 Community:
The grasses, forbs, and shrubs in this plant community provide habitat for many reptiles including western rattlesnake, bullsnake, and racer. If water is available for breeding, spadefoot toads and tiger salamanders may be found here. The structural diversity in the plant community on this site provides habitat for Cassin’s sparrow and lark bunting. Ferruginous and Swainson’s hawks are commonly seen. Small mammals such as white-tailed jackrabbit, badger, swift fox, plains pocket gopher, and several species of mice are common. Pronghorn is a typical ungulate.

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

Increased Shrubs, Annuals and Bare Ground Plant Community:
Reptiles using this community are similar to the reference community species. As bare ground increases, conditions improve for Texas horned lizard. Increases in broom snakeweed, shadscale, and plains greasebush cause the bird community to shift from Cassin’s sparrow to the grasshopper sparrow. Most mammals are similar to the reference community, however black-tailed jackrabbit and desert cottontail use may increase because of the increased bare ground and shrubs.

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 Community - (300) (0.08)

1.2 Community - (150) (0.04)

These rates are guidelines and developing a range plan requires an on-site visit.

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 due to the shallowness of the soil. This site is dominated by soils in hydrologic group D. Infiltration is low 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

Possible fire wood and fence posts.

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 complete to Provisional level

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

Plains greasebush was dropped from the species list and narrative since it is not expected to occur on shallow sites.

Updated. All “Required” items 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.

Each Alternative State/Community:

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

Supporting Information (Site Interpretations, Associated and Similar Sites, Inventory Data References, Agency/State Correlation, References):

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

Animal Community
Wildlife interpretations, general narrative, updated (Provisional “+”). Interpretations for individual plant community states/phases, pending.

Livestock Interpretations updated to reflect the Plant Community name revisions. The stocking rate calculations remain the same since they are based on the “Previously Approved” Total Annual Production table.

The stocking rate calculations will be updated when Total Annual Production and Plant
Community annual production is revised at the next “Approved” level.

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

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

Supporting Information:

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

Rangeland Health Reference Sheet:

From “Previously Approved” ESD (2004). Will be updated at the next “Approved” level.

Note: There are no Gypsum Breaks located 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, % 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
Laura L. Craven MLRA Project Leader NRCS
Ben P. Berlinger Rangeland Management Specialist NRCS Retired
Kimberly A. Diller Ecological Site Specialist NRCS

Approval

Kirt Walstad, 9/07/2023

Acknowledgments

Project Staff:
Kimberly Diller, Ecological Site Specialist, NRCS MLRA, Pueblo 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, Dept. of the Army, Fort Carson, CO
John Lamman, Rangeland Mgt. 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, CO State Biologist; 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, 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

Indicators

Number and extent of rills:
None on flatter slopes. Short, widely spaced rills are present on steep slopes with gypsum and shale outcrop.
Presence of water flow patterns:
On slopes of 15 percent or less, water patterns will be broken and irregular in appearance. Flow patterns will be evident as slope and gypsum outcrops increase (especially following intense storms). They will be short and connected with occasional debris dams or vegetative barriers.
Number and height of erosional pedestals or terracettes:
Small pedestals and terracettes exist, ranging in height from
0.25 – 0.5 inches. They are few in number and confined to the steeper slopes (>15 percent) and gypsum outcrops.
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
7-12 percent or less bare ground, with bare patches generally less than 3-5 inches in diameter. Extended drought can cause bare ground to increase upwards to 15-20 percent with bare patches reaching upwards to 12-18 inches in diameter.
Number of gullies and erosion associated with gullies:
Typically none. However, on steep slopes, gullies may be up to 5 feet in length and wide-spread, not exceeding 6 inches deep.
Extent of wind scoured, blowouts and/or depositional areas:
None to slight wind scour. However, small depositional areas occur as the slope decreases.
Amount of litter movement (describe size and distance expected to travel):
Minimal and short on flatter slopes. Small herbaceous litter movement is associated with water flow patterns and may move as much as 1-3 feet or more down slope during severe precipitation events, especially on steeper slopes.
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
Stability class rating is anticipated to be 4-5 in interspace at soil surface. These values need verification at reference site.
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Average SOM is 1-2 percent. Soils are shallow to moderately deep to gypsum bedrock. The A horizon is light brownish-gray, very fine granular structure, approximately 0-2 inches in depth.
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Raindrop impact is reduced by the diverse grass, forb, shrub functional/structural groups and root structure. This slows overland flow and provides increased time for infiltration to occur. Extended drought, wildfire or both may reduce basal density, canopy cover, and litter amounts (primarily from tall, warm-season bunch and rhizomatous grasses), resulting in decreased infiltration and increased runoff on steep slopes following intense rainfall events.
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
None
Functional/Structural Groups (list in order of descending dominance by above-ground annual-production or live foliar cover using symbols: >>, >, = to indicate much greater than, greater than, and equal to):

Dominant:
Warm-season mid sod-formers >

Sub-dominant:
Shrubs = warm-season mid bunchgrass > cool-season mid bunchgrass > warm-season short bunchgrass > cool-season mid rhizomatous >

Other:
Warm-season forbs > leguminous forbs > cool-season forbs = sedges > short trees

Additional:
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
Typically minimal. Expect short and mid bunchgrass mortality and decadence during and following drought. Bunchgrasses may show signs of decadence on steeper inaccessible slopes and lack of wildfire events.
Average percent litter cover (%) and depth ( in):
Litter cover during and following extended drought ranges from 5-15 percent.
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
150 lbs. /ac. low precipitation years; 300 lbs. /ac. average precipitation years; 500 lbs. /ac. above average precipitation years. After extended drought or the first growing season following wildfire, production will be significantly reduced.
Potential invasive (including noxious) species (native and non-native). List species which BOTH characterize degraded states and have the potential to become a dominant or co-dominant species on the ecological site if their future establishment and growth is not actively controlled by management interventions. Species that become dominant for only one to several years (e.g., short-term response to drought or wildfire) are not invasive plants. Note that unlike other indicators, we are describing what is NOT expected in the reference state for the ecological site:
Invasive plants should not occur in reference plant community. Cheatgrass, Russian thistle, burningbush, and other non-native annuals may invade following extended drought or fire if a seed source is available.
Perennial plant reproductive capability:
The only limitations are weather related, wildfire, and natural disease that may temporarily reduce reproductive capability.