Natural Resources
Conservation Service

Ecological site R067AY112WY

Gravelly (Gr)

Last updated: 9/07/2023
Accessed: 11/21/2024

Home / Esd catalog / MLRA 067A / Ecological site R067AY112WY

USC

Metric

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.

Click to explore map

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): 067A–Central High Plains, Northern Part

MLRA 67A-Central High Plains, Northern Part is located in southeastern Wyoming (58 percent), the southwestern portion of the Nebraska panhandle (38 percent), and extreme northeastern Colorado (4 percent). It is comprised of rolling plains, upland breaks, and river valleys. The major rivers are the North Platte and Laramie. The headwaters of these systems are in the Rocky Mountains. Other tributaries include Crow, Horse, and Lodgepole Creeks. This MLRA is traversed by Interstate 25 and Interstate 80, and by U.S. Highways 26, 30 and 85. Major land uses include rangeland (71 percent), cropland (21 percent), pasture and hayland (1 percent), urban (3 percent), and miscellaneous (4 percent). Cities in this area include Cheyenne, Torrington, and Wheatland, WY; and Kimball, Oshkosh, and Scottsbluff, NE. Land ownership is mostly private. Areas of interest include Scotts Bluff National Monument, Chimney Rock and Fort Laramie National Historic Sites; Hawk Springs, Lake Minatare, and Wildcat Hills State Recreation Areas; Ash Hollow and Guernsey State Parks.

The elevations in MLRA 67A range from approximately 3,300 to 6,200 feet. The average annual precipitation in this area ranges from 13 to17 inches per year, but may increase up to 18 inches per year, in localized areas. Precipitation occurs mostly during the growing season from rapidly developing thunderstorms. Mean annual air temperature ranges from 47 degrees Fahrenheit in the western part to 52 degrees Fahrenheit in the eastern part. Summer temperatures may exceed 100 degrees Fahrenheit. Winter temperatures may drop to sub-zero, and snowfall varies from 20 to 50 inches per year.

Classification relationships

MLRA 67A is in the Western Great Plains Range and Irrigation Land Resource Region. It is in the High Plains Section, of the Great Plains Province, of the Interior Plains (USDA, 2006). MLRAs can be defined by climate, landscapes, geology, and annual precipitation zones (PZ). Other features such as landforms, soil properties, and key vegetation further refine these concepts, and are described at the Ecological Site Description (ESD) level.

Revision Notes:
The Gravelly (Gr) Ecological Site was developed using an earlier version of the Gravelly (Gr) 12-17” Precipitation Zone and Gravelly Loamy 12-17” Precipitation Zone Ecological Site Dscriptions, respectively (2005, updated 2008). The earlier versions of the Gravelly and Gravelly Loamy ESD’s were based on input from NRCS (formerly Soil Conservation Service) and historical information obtained from the Gravelly (Gr) and Gravelly Loamy Range Site Descriptions (1988). This ESD meets the Provisional requirements of the National Ecological Site Handbook (NESH). This ESD will continue refinement toward an Approved status according to the NESH.

Ecological site concept

The Gravelly Ecological Site is a run-off site with soil over 40 inches deep. The soil is not saline or alkaline, has a high volume of of coarse fragments on the surface and throughout the profile, and gravelly surface surface soil textures.

Associated sites

R067AY122WY	Loamy (Ly) This ecological site is commonly adjacent.
R067AY150WY	Sandy (Sy) This ecological site is commonly adjacent.

R067AY122WY

Loamy (Ly)

This ecological site is commonly adjacent.

R067AY150WY

Sandy (Sy)

This ecological site is commonly adjacent.

Table 1. Dominant plant species

Tree	Not specified
Shrub	(1) Yucca glauca (2) Opuntia polyacantha
Herbaceous	(1) Schizachyrium scoparium (2) Hesperostipa comata

Download full description

Physiographic features

This site occurs on summits or shoulders of the hills, on knobs, and on crests or nose slopes of the ridges on the uplands.

Table 2. Representative physiographic features

Landforms	(1) Upland > Hill (2) Ridge (3) Knob
Runoff class	Very low to medium
Flooding frequency	None
Ponding frequency	None
Elevation	3 – 5 ft
Slope	1 – 50%
Water table depth	80 – 200 in
Aspect	Aspect is not a significant factor

Climatic features

Wide fluctuations in precipitation may occur from year to year, as well as occasional periods of drought (longer than one year in duration). Two-thirds of the annual precipitation occurs during the growing season from April to September. The mean annual air temperature (MAAT) ranges from 47 degrees Fahrenheit in the western part to 52 degrees Fahrenheit in the eastern part. Cold air outbreaks from Canada in winter move rapidly from northwest to southeast and account for extreme minimum temperatures. Chinook winds may also occur in winter and bring rapid rises in temperature. Extreme storms may occur during the winter, but most severely affect ranch operations during the late winter and spring months. High-intensity afternoon thunderstorms may arise in summer. Wind speed averages about 8 miles per hour, ranging from 10 during the spring to 7 during late summer. Daytime winds are generally stronger than nighttime and occasional strong storms may bring brief periods of high winds with gusts to more than 75 mph. The average length of the freeze-free period (28 degrees Fahrenheit) is 150 days from May 4 to October 1. The average frost-free period (32 degrees Fahrenheit) is 128 days from May 16 to September 21. Growing season increases from west to east (Wyoming to Nebraska). Growth of native cool-season plants begins about April 1 and continues to mid-June. Native warm-season plants begin growth about May 15 and continue to about August 15. Regrowth of cool-season plants occur in September in most years, depending upon moisture.

Table 3. Representative climatic features

Frost-free period (characteristic range)	85-117 days
Freeze-free period (characteristic range)	119-135 days
Precipitation total (characteristic range)	16-17 in
Frost-free period (actual range)	84-123 days
Freeze-free period (actual range)	116-137 days
Precipitation total (actual range)	14-18 in
Frost-free period (average)	103 days
Freeze-free period (average)	128 days
Precipitation total (average)	16 in

Characteristic range

Actual range

Bar

Line

Figure 2. Monthly precipitation range

Characteristic range

Actual range

Bar

Line

Figure 3. Monthly minimum temperature range

Characteristic range

Actual range

Bar

Line

Figure 4. Monthly maximum temperature range

Bar

Line

Figure 5. Monthly average minimum and maximum temperature

Figure 6. Annual precipitation pattern

Figure 7. Annual average temperature pattern

Climate stations used

(1) CHEYENNE [USW00024018], Cheyenne, WY
(2) CHUGWATER [USC00481730], Chugwater, WY
(3) HARRISBURG 12WNW [USC00253605], Harrisburg, NE
(4) KIMBALL 2NE [USC00254440], Kimball, NE
(5) OLD FT LARAMIE [USC00486852], Yoder, WY
(6) OSHKOSH [USC00256385], Oshkosh, NE
(7) SCOTTSBLUFF HEILIG AP [USW00024028], Scottsbluff, NE
(8) WHEATLAND 4 N [USC00489615], Wheatland, WY
(9) PHILLIPS [USC00487200], LaGrange, WY
(10) BRIDGEPORT [USC00251145], Bridgeport, NE

Soil features

The soils on this site are typically very deep, well to excessively drained soils that formed from old gravelly alluvium or outwash. They typically have a moderately rapid to very rapid permeability class, but ranges to moderate in some soils. The available water capacity is very low to low. The soil moisture regime is typically aridic ustic. The soil temperature regime is mesic.

The surface layer of the soils in this site are typically gravelly sandy loam, gravelly loam, or sandy loam, but may include gravelly fine sandy loam or very gravelly sandy loam. The surface layer ranges from a depth of 2 to 7 inches thick. The subsoil is typically very gravelly coarse sand, gravelly loamy coarse sand, gravelly coarse sand, or gravelly sand, but may include very gravelly sand, very gravelly loamy sand, gravelly sandy loam, or very gravelly sandy loam. Rock fragments are typically greater than 15 percent and can range as high as 60 percent. Soils in this site are typically leached of carbonates to depths of greater than 60 inches, but a few soils may have carbonates at the surface and throughout the soil profile. Exposed areas of gravel are inherent to this site. Areas with little or no surface gravel are susceptible to erosion by water and wind. The hazard of water erosion accelerates with increasing slope.

Surface soil structure is typically granular, and structure below the surface is typically single grain; massive or weak subangular blocky structure may be present in some horizons. Soil structure describes the manner in which soil particles are aggregated and defines the nature of the system of pores and channels in a soil.

Major soil series correlated to this ecological site: Aberone, Blueridge, Cascajo, Dix, Eckley, and Peetz.

Other soil series that have been correlated to this site: Nidix and Willowman.

The attributes listed below represent 0-40 inches in depth or to the first restrictive layer.

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

Figure 8. Soil Profile Image-Dix gravelly loam, Cheyenne County, NE. Depth is marked in feet.

Table 4. Representative soil features

Parent material	(1) Alluvium (2) Outwash
Surface texture	(1) Gravelly sandy loam (2) Gravelly loam (3) Sandy loam
Family particle size	(1) Loamy
Drainage class	Well drained to excessively drained
Permeability class	Moderately rapid to very rapid
Soil depth	80 in
Surface fragment cover <=3"	5 – 45%
Surface fragment cover >3"	5%
Available water capacity (Depth not specified)	0.8 – 3.6 in
Calcium carbonate equivalent (Depth not specified)	15%
Electrical conductivity (Depth not specified)	2 mmhos/cm
Soil reaction (1:1 water) (Depth not specified)	6.6 – 8.4
Subsurface fragment volume <=3" (Depth not specified)	15 – 60%
Subsurface fragment volume >3" (Depth not specified)	10%

Ecological dynamics

The information in this ESD, including the State-and-Transition Model (STM) diagram, was developed using archeological and historical data, professional experience, and scientific studies. The information is representative of a dynamic set of plant communities that represent the complex interaction of several ecological processes. The plant composition has been determined by study of rangeland relic areas, areas protected from excessive disturbance, seasonal use pastures, short duration/time-controlled grazing strategies, and historical accounts.

The Gravelly ecological site is characterized by three states: Reference, Sod-bound, and Increased Bare Ground. The Reference State is characterized by warm and cool-season bunchgrasses (little bluestem and needle and thread), and warm-season shortgrass (blue grama). Secondary grasses include cool-season rhizomatous midgrass (western wheatgrass), and a minor component of grass-likes (threadleaf sedge): forbs including phlox, sandwort, and nailwort, and a minor component of shrubs. The Sod-bound State is characterized by blue grama and threadleaf sedge. The Increased Bare Ground State is characterized by remnant blue grama and threadleaf sedge, Fendler threeawn, phlox, increased broom snakeweed, and invasive annuals such as cheatgrass.

As this site begins to deteriorate from a combination of frequent and severe grazing during the growing season, grasses such as little bluestem, needle and thread, and sideoats grama, decrease in both frequency and production. Grasses such as blue grama and threadleaf sedge increase. Under continued frequent and severe defoliation with no rest periods, rhizomatous wheatgrasses such as western wheatgrass also begin to decrease. If continued, the plant community becomes sod-bound, and all mid- to tallgrasses may eventually be removed from the plant community. Over the long-term, this continuous use in combination with high stock densities results in a broken sod, with areas of bare ground developing, and species such as broom snakeweed and annual bromes (cheatgrass), invading. Once these events have occurred, it is difficult for native perennial plants to reestablish.

The degree of grazing has a significant impact on the ecological dynamics of the site. This region was historically occupied by large grazing animals, such as bison, elk, pronghorn, and mule deer. Grazing by these large herbivores, along with climatic and seasonal weather fluctuations, had a major influence on the ecological dynamics of the site. Deer and pronghorn are widely distributed throughout the MLRA. Secondary influences of herbivory by species such as prairie dogs and other small rodents, insects, and root-feeding organisms continues to impact the vegetation.

Historically, grazing patterns by herds of large ungulates were driven by water distribution, precipitation events, drought events, and fire. It is believed that grazing periods would have been shorter, followed by longer recovery periods. These large migrating herds impacted the ecological processes of nutrient and hydrologic cycles, by urination, trampling (incorporation of litter into the soil surface), and breaking of surface crust, (which increases water infiltration).

Today, livestock grazing, especially beef cattle has been a major influence on the ecological dynamics of the site. Grazing management, coupled with the effects of annual climatic variations, largely dictates the plant communities for the site.

Recurrent 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. Drought events since 2002 have significantly increased mortality of blue grama and buffalograss in some locales.

This site developed with occasional fire as part of the ecological processes. Historic fire frequency (pre-industrial) is estimated at 10 to14 years (Guyette, 2012), randomly distributed, and started by lightning at various times throughout the growing season. Early human inhabitants also were likely to start fires for various reasons (deliberate or accidental). It is believed that fires were set as a management tool for attracting herds of large migratory herbivores (Stewart, 2002). The impact of fire over the past 100 years has been relatively insignificant due to the human control of wildfires and the lack of acceptance of prescribed fire as a management tool.

Mechanical treatment consisting of contour pitting, furrowing, terracing, chiseling, and disking has been practiced in the past. It was theorized that the use of this high-input technology would improve production and plant composition on rangeland. These high-cost practices have shown to have no significant long-term benefits on production or plant composition and have only resulted in a permanently rough ground surface. Prescribed grazing that mimics the historic grazing of herds of migratory herbivores, as described earlier, has been shown to result in desired improvements based on management goals for this ecological site.

Eastern Colorado was strongly affected by extended drought conditions in the “Dust Bowl” period of the 1930’s, 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. Long-term effects of these latest drought events have yet to be determined. Growth of native cool-season plants begins about April 1 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 in most years, depending on the availability of moisture.

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. Sod-bound State

3. Increased Bare Ground State

T1A	-	Excessive grazing. Lack of fire.
T2A	-	Excessive grazing. Lack of fire.

State 1 submodel, plant communities

1.1. Schizachyrium scoparium-Bouteloua gracilis (little bluestem-blue grama).

1.2. Bouteloua gracilis-Hesperostipa comata (blue grama-needle and thread).

1.1A	-	Excessive grazing. Lack of fire.
1.2A	-	Prescribed grazing. Prescribed fire.

State 2 submodel, plant communities

2.1. Bouteloua gracilis-Carex filifolia (blue grama-threadleaf sedge).

State 3 submodel, plant communities

3.1. Aristida purpurea-Bromus tectorum (Fendler threeawn-cheatgrass).

State 1
Reference State

The Reference State is characterized by two distinct plant community phases. These plant communities, and various successional stages between them, represent the natural range of variability within the Reference State.

Dominant plant species

soapweed yucca (Yucca glauca), shrub
plains pricklypear (Opuntia polyacantha), shrub
little bluestem (Schizachyrium scoparium), grass
blue grama (Bouteloua gracilis), grass
needle and thread (Hesperostipa comata), grass

Community 1.1
Schizachyrium scoparium-Bouteloua gracilis (little bluestem-blue grama).

Figure 9. Gravelly site, Kimball County, NE

This is the interpretive plant community for the Gravelly Ecological Site. This community developed with grazing by large herbivores and is suited to grazing by domestic livestock. Historically, fires likely occurred infrequently, and were randomly distributed. This plant community can be found on areas where grazed plants receive adequate periods of recovery during the growing season. The potential vegetation is about 75 to 85 percent grasses and grass-likes, 15 to 20 percent forbs, and 0 to 5 percent woody plants. The major grasses include little bluestem, needle and thread, blue grama, and western wheatgrass. Secondary grasses include bluebunch wheatgrass, sideoats grama, and Indian ricegrass. Minor grasses include hairy grama, Fendler threeawn, plains muhly, and sand dropseed. Dominant forbs are dotted blazing star (also known as dotted gayfeather), hairy false goldenaster, and slimflower scurfpea. Other forbs include cuman ragweed (also known as western ragweed), and scarlet beeblossom. Legumes include spiny milkvetch, locoweeds, purple prairie clover, and slimflower scurfpea. Other forbs include cushion plants such as pussytoes, spiny phlox, Hooker’s sandwort, and sessile nailwort. A minor component of subshrubs and shrubs, such as prairie sagewort (also known as fringed sagewort) and field sagewort (also known as green sagewort), plains pricklypear, spreading buckwheat, and small soapweed are also present. The total annual production (air-dry weight) is about 800 pounds per acre during an average year, but it can range from about 550 pounds per acre in unfavorable years to about 1,100 pounds per acre in above-average years. Community dynamics (nutrient and water cycles and energy flow) are functioning properly. Infiltration rates are moderate and soil erosion is low. Litter is properly distributed where vegetative cover is continuous. Decadence and natural plant mortality are low. This community is resistant to many disturbances except heavy, continuous grazing, tillage, or development into urban or other uses.

Dominant plant species

soapweed yucca (Yucca glauca), shrub
plains pricklypear (Opuntia polyacantha), shrub
little bluestem (Schizachyrium scoparium), grass
blue grama (Bouteloua gracilis), grass
needle and thread (Hesperostipa comata), grass

Figure 10. Annual production by plant type (representative values) or group (midpoint values)

Figure 11. Plant community growth curve (percent production by month). WY1107, 12-14 SP Upland sites, cool-season/warm-season co-dominant. 12-14" Precipitation Zone (PZ), Southern Plains (SP), with cool-season and warm-season (grass) species..

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	3	10	20	28	21	10	5	3	0	0

Community 1.2
Bouteloua gracilis-Hesperostipa comata (blue grama-needle and thread).

Forbs and shrubs are still present in small amounts. This plant community is at risk of losing warm-season midgrasses and palatable forbs and shrubs. The dominant grasses are needle and thread and blue grama. Little bluestem is still present as a secondary grass in the community. Significant forbs include spiny phlox, Hooker’s sandwort, hairy false goldenaster, cuman ragweed, slimflower scurfpea, and prairie (fringed) sagewort. Shrubs that have increased are yucca, broom snakeweed, and pricklypear cactus. The total annual production (air-dry weight) is about 600 pounds per acre during an average year, but it can range from about 400 pounds per acre in unfavorable years to about 800 pounds per acre in above-average years. Total aboveground biomass has been reduced. Reduction of warm-season midgrasses and cool-season rhizomatous wheatgrasses, nitrogen-fixing forbs, and increased sod-forming grasses and grass-likes, have begun to alter the biotic integrity of this community. Water and nutrient cycles may be impaired. Nearly all plant species typically found in the Reference Plant Community are present and respond to changes in grazing management.

Dominant plant species

soapweed yucca (Yucca glauca), shrub
plains pricklypear (Opuntia polyacantha), shrub
blue grama (Bouteloua gracilis), grass
needle and thread (Hesperostipa comata), grass

Figure 12. Plant community growth curve (percent production by month). WY1107, 12-14 SP Upland sites, cool-season/warm-season co-dominant. 12-14" Precipitation Zone (PZ), Southern Plains (SP), with cool-season and warm-season (grass) species..

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	3	10	20	28	21	10	5	3	0	0

Pathway 1.1A
Community 1.1 to 1.2

Frequent and severe defoliation without adequate recovery between grazing events and lack of fire shifts this plant community toward the 1.2 Community. Drought accelerates this process. Biotic integrity and the water and nutrient cycles may become impaired.

Pathway 1.2A
Community 1.2 to 1.1

Grazing that allows for adequate recovery between grazing events, proper stocking rates, and prescribed fire shift this community back to the Reference Plant Community.

Conservation practices

Prescribed Burning
Prescribed Grazing

State 2
Sod-bound State

This is a very stable state, resistant to change due to the high tolerance of blue grama and threadleaf sedge to grazing, the development of a shallow root system (root pan), and subsequent changes in hydrology and nutrient cycling. The loss of other functional/structural groups such as cool-season bunch and rhizomatous grasses, forbs, and shrubs reduces the biodiversity productivity of this site. An ecological threshold has been crossed and a significant amount of production and diversity has been lost when compared to the Reference State. Significant biotic and soil changes have negatively impacted energy flow and the nutrient and hydrologic cycles.

Dominant plant species

soapweed yucca (Yucca glauca), shrub
plains pricklypear (Opuntia polyacantha), shrub
blue grama (Bouteloua gracilis), grass
threadleaf sedge (Carex filifolia), grass

Community 2.1
Bouteloua gracilis-Carex filifolia (blue grama-threadleaf sedge).

The mid-grasses and palatable forbs have been eliminated. The dominant species are blue grama and threadleaf sedge. These species have developed into a sod-bound condition occurring in localized colonies exhibiting a mosaic appearance. Needle and thread may persist, if seasonal grazing use occurs after awn development. Sideoats grama and little bluestem may still be present in small amounts on steeper slopes. There may also be remnants of rhizomatous wheatgrasses. Fendler threeawn has increased. Forbs that continue to increase are cuman ragweed (western ragweed), hairy false goldenaster, spiny phlox, Hooker’s sandwort, and spreading buckwheat. Prairie sagewort (also known as fringed sagebrush) and small soapweed also increase. Compared to the Reference Plant Community, nearly all the midgrasses are gone and weedy species have invaded the area. Undesirable grasses, forbs, and other plants have increased. Plant diversity is very low. The plant community lacks diversity and is resistant to change. Energy flow and the water and mineral cycles have been negatively affected. Litter levels are very low and unevenly distributed. The total annual production (air-dry weight) is about 400 pounds per acre during an average year, but it can range from about 350 pounds per acre in unfavorable years to about 500 pounds per acre in above-average years.

Dominant plant species

soapweed yucca (Yucca glauca), shrub
plains pricklypear (Opuntia polyacantha), shrub
blue grama (Bouteloua gracilis), grass
threadleaf sedge (Carex filifolia), grass

Figure 13. Plant community growth curve (percent production by month). WY1104, 12-14SP upland sites w/ warm. 12-14" Precipitation Zone, Southern Plains (SP) with warm-season (grass) species.

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	20	35	30	5	5	0	0	0

State 3
Increased Bare Ground State

An ecological threshold has been crossed. The Increased Bare Ground State denotes changes in infiltration, runoff, aggregate stability, and species composition. The changes in water movement and the plant community trigger changes in hydrologic functionality, biotic integrity, and soil and site stability. Infiltration, runoff, and soil erosion vary depending upon the vegetation present. Erosion and loss of organic matter and carbon reserves are concerns.

Dominant plant species

soapweed yucca (Yucca glauca), shrub
plains pricklypear (Opuntia polyacantha), shrub
Fendler threeawn (Aristida purpurea var. longiseta), grass
cheatgrass (Bromus tectorum), grass
Russian thistle (Salsola), other herbaceous
burningbush (Bassia scoparia), other herbaceous

Community 3.1
Aristida purpurea-Bromus tectorum (Fendler threeawn-cheatgrass).

Bare ground, cushion plants, and cryptogamic crusts have significantly increased. Remnant grasses include blue and hairy grama and Fendler threeawn. Annual grasses such as cheatgrass and sixweeks fescue have increased or invaded. The dominant forbs include field sagewort, hairy false goldenaster, and annual weeds such as burningbush and Russian thistle. Cushion plants such as spiny phlox, Hooker’s sandwort, and spiny milkvetch (also known as mat loco), and shrubs such as pricklypear, broom snakeweed, and small soapweed persist. Forage palatability for livestock is low. The total annual production (air-dry weight) is about 300 pounds per acre during an average year, but it can range from about 100 pounds per acre in unfavorable years to about 400 pounds per acre in above-average years. NOTE: This plant community is highly variable in both species composition and production. Average annual production should be determined on site.

Dominant plant species

soapweed yucca (Yucca glauca), shrub
plains pricklypear (Opuntia polyacantha), shrub
Fendler threeawn (Aristida purpurea var. longiseta), grass
cheatgrass (Bromus tectorum), grass

Figure 14. Plant community growth curve (percent production by month). WY1104, 12-14SP upland sites w/ warm. 12-14" Precipitation Zone, Southern Plains (SP) with warm-season (grass) species.

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	20	35	30	5	5	0	0	0

Transition T1A
State 1 to 2

Frequent and severe defoliation and lack of fire shift this plant community across an ecological threshold toward the Sod-bound State. Biotic integrity and hydrologic function are impaired.

Transition T2A
State 2 to 3

Long-term frequent and severe defoliation without adequate recovery between grazing events and lack of fire cause a shift across an ecological threshold to the Increased Bare Ground State. The hazard of erosion and the loss of organic matter, along with invasion of introduced plants and noxious weeds, are resource concerns.

Additional community tables

Table 5. Community 1.1 plant community composition

Group	Common name	Symbol	Scientific name	Annual production (lb/acre)	Foliar cover (%)
Grass/Grasslike
1	12			165–248
	little bluestem	SCSC	Schizachyrium scoparium	138–193	–
	sideoats grama	BOCU	Bouteloua curtipendula	28–55	–
2	12			55–165
	needle and thread	HECO26	Hesperostipa comata	55–83	–
	bluebunch wheatgrass	PSSP6	Pseudoroegneria spicata	0–83	–
3	12			55–83
	blue grama	BOGR2	Bouteloua gracilis	55–83	–
4	12			28–55
	thickspike wheatgrass	ELLA3	Elymus lanceolatus	28–55	–
	western wheatgrass	PASM	Pascopyrum smithii	28–55	–
5	12			28–55
	Grass, perennial	2GP	Grass, perennial	0–28	–
	Indian ricegrass	ACHY	Achnatherum hymenoides	0–28	–
	hairy grama	BOHI2	Bouteloua hirsuta	0–28	–
	prairie sandreed	CALO	Calamovilfa longifolia	0–28	–
	plains reedgrass	CAMO	Calamagrostis montanensis	0–28	–
	prairie Junegrass	KOMA	Koeleria macrantha	0–28	–
	plains muhly	MUCU3	Muhlenbergia cuspidata	0–28	–
	Sandberg bluegrass	POSE	Poa secunda	0–28	–
	sand dropseed	SPCR	Sporobolus cryptandrus	0–28	–
	threeawn	ARIST	Aristida	0–11	–
6	12			28–55
	threadleaf sedge	CAFI	Carex filifolia	28–55	–
	sedge	CAREX	Carex	0–28	–
9	15			180–270
	little bluestem	SCSC	Schizachyrium scoparium	150–210	–
	sideoats grama	BOCU	Bouteloua curtipendula	30–60	–
10	15			60–180
	needle and thread	HECO26	Hesperostipa comata	60–90	–
	bluebunch wheatgrass	PSSP6	Pseudoroegneria spicata	0–90	–
11	15			60–90
	blue grama	BOGR2	Bouteloua gracilis	60–90	–
12	15			30–60
	thickspike wheatgrass	ELLA3	Elymus lanceolatus	30–60	–
	western wheatgrass	PASM	Pascopyrum smithii	30–60	–
13	15			30–60
	Grass, perennial	2GP	Grass, perennial	0–30	–
	Indian ricegrass	ACHY	Achnatherum hymenoides	0–30	–
	threeawn	ARIST	Aristida	0–30	–
	hairy grama	BOHI2	Bouteloua hirsuta	0–30	–
	prairie sandreed	CALO	Calamovilfa longifolia	0–30	–
	plains reedgrass	CAMO	Calamagrostis montanensis	0–30	–
	prairie Junegrass	KOMA	Koeleria macrantha	0–30	–
	plains muhly	MUCU3	Muhlenbergia cuspidata	0–30	–
	Sandberg bluegrass	POSE	Poa secunda	0–30	–
	sand dropseed	SPCR	Sporobolus cryptandrus	0–30	–
14	15			30–60
	threadleaf sedge	CAFI	Carex filifolia	30–60	–
	sedge	CAREX	Carex	0–30	–
Forb
7	12			83–110
	Forb, perennial	2FP	Forb, perennial	0–28	–
	Cuman ragweed	AMPS	Ambrosia psilostachya	0–11	–
	pussytoes	ANTEN	Antennaria	0–11	–
	sandwort	ARENA	Arenaria	0–11	–
	prairie sagewort	ARFR4	Artemisia frigida	0–11	–
	prairie clover	DALEA	Dalea	0–11	–
	buckwheat	ERIOG	Eriogonum	0–11	–
	scarlet beeblossom	GACO5	Gaura coccinea	0–11	–
	hairy false goldenaster	HEVI4	Heterotheca villosa	0–11	–
	dotted blazing star	LIPU	Liatris punctata	0–11	–
	evening primrose	OENOT	Oenothera	0–11	–
	nailwort	PARON	Paronychia	0–11	–
	beardtongue	PENST	Penstemon	0–11	–
	phlox	PHLOX	Phlox	0–11	–
	lemon scurfpea	PSLA3	Psoralidium lanceolatum	0–11	–
	ragwort	SENEC	Senecio	0–11	–
	scarlet globemallow	SPCO	Sphaeralcea coccinea	0–11	–
	greenthread	THELE	Thelesperma	0–11	–
15	15			90–120
	Forb, perennial	2FP	Forb, perennial	0–30	–
	Cuman ragweed	AMPS	Ambrosia psilostachya	0–30	–
	pussytoes	ANTEN	Antennaria	0–30	–
	sandwort	ARENA	Arenaria	0–30	–
	prairie sagewort	ARFR4	Artemisia frigida	0–30	–
	prairie clover	DALEA	Dalea	0–30	–
	buckwheat	ERIOG	Eriogonum	0–30	–
	scarlet beeblossom	GACO5	Gaura coccinea	0–30	–
	hairy false goldenaster	HEVI4	Heterotheca villosa	0–30	–
	dotted blazing star	LIPU	Liatris punctata	0–30	–
	evening primrose	OENOT	Oenothera	0–30	–
	nailwort	PARON	Paronychia	0–30	–
	beardtongue	PENST	Penstemon	0–30	–
	phlox	PHLOX	Phlox	0–30	–
	lemon scurfpea	PSLA3	Psoralidium lanceolatum	0–30	–
	ragwort	SENEC	Senecio	0–30	–
	scarlet globemallow	SPCO	Sphaeralcea coccinea	0–30	–
	greenthread	THELE	Thelesperma	0–30	–
Shrub/Vine
8				3–28
	Shrub (>.5m)	2SHRUB	Shrub (>.5m)	0–28	–
	soapweed yucca	YUGL	Yucca glauca	0–28	–
	broom snakeweed	GUSA2	Gutierrezia sarothrae	0–11	–
	brittle pricklypear	OPFR	Opuntia fragilis	0–11	–
	plains pricklypear	OPPO	Opuntia polyacantha	0–11	–
16				3–30
	Shrub (>.5m)	2SHRUB	Shrub (>.5m)	0–30	–
	broom snakeweed	GUSA2	Gutierrezia sarothrae	0–30	–
	brittle pricklypear	OPFR	Opuntia fragilis	0–30	–
	plains pricklypear	OPPO	Opuntia polyacantha	0–30	–
	soapweed yucca	YUGL	Yucca glauca	0–30	–

Interpretations

Animal community

Animal Community – Wildlife Interpretations

Reference Plant Community—Little Bluestem, Needle and Thread, Blue Grama:

The predominance of grasses plus high forb diversity in this community favors large grazers such as pronghorn and elk. Suitable thermal and escape cover for mule deer is limited due to low shrub cover. White and black-tailed jackrabbit, badger, and coyote commonly use this community. This community also provides habitat for a wide array of smaller mammals, so diverse prey populations are available for raptors such as ferruginous and Swainson’s hawks. Birds such as nighthawks utilize this community for nesting.

1.2 Community—Blue Grama, Needle and Thread, Decreased Little Bluestem:

The reduction in taller grasses in this community results in decreased use by lark buntings and western meadowlarks. Use by long-billed curlew increases, provided there is standing water within one-quarter mile. Killdeer, horned larks, and McCown’s longspurs also make significant use of this community. Pronghorn may forage in this community.

2.1 Community—Blue Grama, Threadleaf Sedge:

This community provides limited foraging for antelope and other grazers. Ground-nesting birds favoring sparse vegetation may use this community. Long-billed curlews use this community if standing water is present within one-quarter mile. Generally, this is not a target vegetative community for wildlife habitat management.

3.1 Community—Cushion Plants, Threeawn, Cheatgrass, and Annuals:

This community has low habitat value for most wildlife species.

Animal Community – Grazing Interpretations

The following table is a guide to stocking rates for the plant communities described in the Gravelly site. These are conservative estimates for initial planning. On-site conditions vary, and stocking rates should be adjusted based on range inventories, animal kind and class, forage availability (adjusted for slope and distance to water), and the type of grazing system (number of pastures, planned moves, etc.), all of which is determined in the conservation planning process.

The following stocking rates are based on the total annual forage production in a normal year multiplied by 25 percent harvest efficiency of preferred and desirable forage species, divided by 912 pounds of ingested air-dry vegetation for an animal unit per month (Natl. Range and Pasture Handbook, 1997). An animal unit month (AUM) is defined as the amount of forage required by one mature cow for one month.
Plant Community (PC) Production (total lbs. /acre in a normal year) and Stocking Rate (AUMs/acre) are listed below:

Example: Reference PC – (800) (.22)
800 lbs. per acre X 25% Harvest Efficiency = 200 lbs. forage demand for one month. Then, 200 lbs. per acre/912 demand per AUM =.22
Plant Community (PC) Production (lbs.ac) and Stocking Rate (AUM/Acre)
Reference PC - (800) (0.22)
1.2 PC - (600) (0.16)
2.1 PC - (400) (0.11)

An on-site visit is required prior to developing a range plan.

Grazing by domestic livestock is one of the major income-producing industries in the area. Rangelands in this area provide year-long forage under prescribed grazing for cattle, sheep, horses, and other herbivores. During the dormant period, livestock may need supplementation based on reliable forage analysis.

Hydrological functions

Water is the principal factor limiting forage production on this site. This site is dominated by soils in hydrologic groups B and C. Infiltration ranges from moderate to rapid. Runoff potential for this site varies from moderate to high, depending upon soil hydrologic group and ground cover. In many cases, areas with greater than 75 percent ground cover have the greatest potential for high infiltration and lower runoff. An example of an exception would be where shortgrasses form a strong sod. Areas where ground cover is less than 50 percent have the greatest potential for 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 recreational 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 complete to Provisional level.

Annual Production Table is from the “Previously Approved” ESD (2008).

Growth Curves are from the “Previously Approved” ESD (2008).

The Annual Production Table, Species Composition List, and Growth Curves will be reviewed for future updates at Approved level.

Each Alternative State/Community:

Complete to Provisional level.

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

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

Wildlife Interpretations: Plant community names updated. Narrative is from “Previously Approved” ESD (2008). Wildlife species will need to be updated at the next Approved level.

Livestock Interpretations: Plant community names and stocking rates updated.

Hydrology, Recreational Uses, Wood Products, and Other Products carried over from previously “Approved” ESD (2008).

Plant Preferences table removed. Will be released as a technical guide notice by NRCS NE and WY state offices in the future.

Existing NRI or 417 Inventory Data References updated. More field data collection is needed to support this site concept.

Reference Sheet
Rangeland Health Reference Sheet carried over from previously “Approved” ESD (2008).
It will be updated at the next “Approved” level.

“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)

Supporting information

Inventory data references

Data Source: NRI
Number of Records: 5
(3 Gravelly and 2 Gravelly Loamy)
Sample Period: 2006-2013
States: NE, WY
Counties: Garden, Morrill (NE); Platte (WY)

Data Source: 417s
Number of Records: 6 (4 Gravelly and 2 Gravelly Loamy)
Sample Period: 1968-1980
States: NE, WY
Counties: Garden, Morrill (NE); Laramie, Platte (WY)
Data Source: Tier 1 Reconnaissance
Number of Records 3
States: NE
Counties Banner, Kimball, Sioux

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.
Stewart, O.C., H.T. Lewis, and M.K. Anderson. 2002. Forgotten Fires: Native Americans and the Transient Wilderness. University of Oklahoma Press, Norman, OK. 351p.

Other references

Anderson, R.C. 2006. Evolution and origin of the central grassland of North America: Climate, fire, and mammalian grazers. Journal of the Torrey Botanical Society 133:626–647.

Bragg, T.B. 1995. The physical environment of the Great Plains grasslands. In: A. Joern and K.H. Keeler (eds.) The changing prairie, Oxford University Press, Oxford, UK. pp. 49–81.

Branson, D.H. and G.A. Sword. 2010. An experimental analysis of grasshopper community responses to fire and livestock grazing in a northern mixed-grass prairie. Environmental Entomology 39:1441–1446.

Brinson, M.M. 1993. A hydrogeomorphic classification for wetlands. Technical Report WRP–DE–4. U.S. Army Corps of Engineers Waterways Experiment Station, Vicksburg, MS.

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

Coupland, R.T. 1958. The effects of fluctuations in weather upon the grasslands of the Great Plains. Botanical Review 24:273–317.

Davis, S.K., R.J. Fisher, S.L. Skinner, T.L. Shaffer, and R.M. Brigham. 2013. Songbird abundance in native and planted grassland varies with type and amount of grassland in the surrounding landscape. Journal of Wildlife Management 77:908–919.

DeLuca, T.H. and P. Lesica. 1996. Long-term harmful effects of crested wheatgrass on Great Plains grassland ecosystems. Journal of Soil and Water Conservation 51:408–409.

Derner, J.D. and R.H. Hart. 2007. Grazing-induced modifications to peak standing crop in northern mixed-grass prairie. Rangeland Ecology and Management 60:270–276.

Derner, J.D., and A.J. Whitman. 2009. Plant interspaces resulting from contrasting grazing management in northern mixed-grass prairie: Implications for ecosystem function. Rangeland Ecology and Management 62:83–88.

Derner, J.D., W.K. Lauenroth, P. Stapp, and D.J. Augustine. 2009. Livestock as ecosystem engineers for grassland bird habitat in the western Great Plains of North America. Rangeland Ecology and Management 62:111–118.

Dillehay, T.D. 1974. Late Quaternary bison population changes on the southern Plains. Plains Anthropologist 19:180–196.

Dormaar, J.F. and S. Smoliak. 1985. Recovery of vegetative cover and soil organic matter during revegetation of abandoned farmland in a semiarid climate. Journal of Range Management 38:487–491.

Fenneman, N.M., and D.W. Johnson. 1946. Physical divisions of the United States. U.S. Geological Survey, Physiographic Committee. Scale 1:700,000.
Harmoney, K.R. 2007. Grazing and burning Japanese brome (Bromus japonicus) on mixed grass rangelands. Rangeland Ecology and Management 60:479–486.

Heitschmidt, R.K. and L.T. Vermeire. 2005. An ecological and economic risk avoidance drought management decision support system. In: J.A. Milne (ed.) Pastoral systems in marginal environments, 20th International Grasslands Congress, July 2005. p. 178.

Knopf, F.L. 1996. Prairie legacies—Birds. In: F.B. Samson and F.L. Knopf (eds.) Prairie conservation: Preserving North America’s most endangered ecosystem, Island Press, Washington, DC. pp. 135–148.

Knopf, F.L., and F.B. Samson. 1997. Conservation of grassland vertebrates. In: F.B. Samson and F.L. Knopf (eds.) Ecology and conservation of Great Plains vertebrates: Ecological Studies 125, Springer-Verlag, New York, NY. pp. 273–289.

Lauenroth, W.K., O.E. Sala, D.P. Coffin, and T.B. Kirchner. 1994. The importance of soil water in recruitment of Bouteloua gracilis in the shortgrass steppe. Ecological Applications 4:741–749.

Laycock, W.A. 1988. History of grassland plowing and grass planting on the Great Plains. In: J.E. Mitchell (ed.) Impacts of the Conservation Reserve Program in the Great Plains—symposium proceedings, September 16–18, 1987. USDA Forest Service, Rocky Mountain Forest and Range Experiment Station, General Technical Report RM-158.

Malloch, D.W., K.A. Pirozynski, and P.H. Raven. 1980. Ecological and evolutionary significance of mycorrhizal symbioses in vascular plants (a review). Proceedings of the National Academy of Sciences 77:2113–2118.

Ogle, S.M., W.A. Reiners, and K.G. Gerow. 2003. Impacts of exotic annual brome grasses (Bromus spp.) on ecosystem properties of the northern mixed grass prairie. American Midland Naturalist 149:46–58.

Roath, L.R. 1988. Implications of land conversions and management for the future. In: J.E. Mitchell (ed.) Impacts of the Conservation Reserve Program in the Great Plains—symposium proceedings, September 16–18, 1987. USDA Forest Service, Rocky Mountain Forest and Range Experiment Station, General Technical Report RM-158.

Smoliak, S. and J.F. Dormaar. 1985. Productivity of Russian wildrye and crested wheatgrass and their effect on prairie soils. Journal of Range Management 38:403–405.

Smoliak, S., J.F. Dormaar, and A. Johnston. 1972. Long-term grazing effects on Stipa-Bouteloua prairie soils. Journal of Range Management 25:246–250.

Soil Science Division Staff. 2017. Soil survey manual. C. Ditzler, K. Scheffe, and H.C. Monger (eds.) USDA Handbook 18. Government Printing Office, Washington, DC.

Soil Survey Staff. Official Soil Series Descriptions. USDA Natural Resources Conservation Service. Available online. https://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/home/?cid=nrcs142p2_053587. Accessed 15 November, 2017.

Soil Survey Staff. Soil Survey Geographic (SSURGO) database. USDA Natural Resources Conservation Service.

Soil Survey Staff. 2014. Keys to Soil Taxonomy, 12th edition. USDA Natural Resources Conservation Service, Washington, DC.

Soil Survey Staff. 2018. Web Soil Survey. USDA Natural Resources Conservation Service. Available online. https://websoilsurvey.nrcs.usda.gov/app/. Accessed 15 February, 2018.

Soller, D.R. 2001. Map showing the thickness and character of Quaternary sediments in the glaciated United States east of the Rocky Mountains. U.S. Geological Survey Miscellaneous Investigations Series I-1970-E, scale 1:3,500,000.

U.S. Army Corps of Engineers. 1987. Corps of Engineers wetlands delineation manual. Wetlands Research Program Technical Report Y-87-1 Available online. (http://www.lrh.usace.army.mil/Portals/38/docs/USACE%2087%20Wetland%20Delineation%20Manual.pdf). Waterways Experiment Station, Vicksburg, MS.

U.S. Department of Agriculture, Natural Resources Conservation Service. Glossary of landform and geologic terms. National Soil Survey Handbook, Title 430-VI, Part 629.02c. Available online. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/ref/?cid=nrcs142p2_054242. Accessed 16 January, 2018.

U.S. Department of Agriculture, Natural Resources Conservation Service. 2010a. Field indicators of hydric soils in the United States, version 7.0. L.M. Vasilas, G.W. Hurt, and C.V. Noble (eds.) USDA-NRCS, in cooperation with the National Technical Committee for Hydric Soils.

U.S. Department of Agriculture, Natural Resources Conservation Service. 2013a. Climate data. National Water and Climate Center. Available online. http://www.wcc.nrcs.usda.gov/climate. Accessed 13 October, 2017.

U.S. Department of Agriculture, Natural Resources Conservation Service. 2013b. National Soil Information System. Available online. https://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/survey/geo/?cid=nrcs142p2_053552. Accessed 30 October, 2017.

U.S. Department of the Interior, Geological Survey. 2008. LANDFIRE 1.1.0 Vegetation Dynamics Models. Available online. http://landfire.cr.usgs.gov/viewer/.

U.S. Department of the Interior, Geological Survey. 2011. LANDFIRE 1.1.0 Existing Vegetation Types. Available online. http://landfire.cr.usgs.gov/viewer/.

Willeke, G.E. 1994. The national drought atlas [CD ROM]. U.S. Army Corps of Engineers, Water Resources Support Center, Institute for Water Resources Report 94-NDS-4.

Wilson, S.D., and J.M. Shay. 1990. Competition, fire, and nutrients in a mixed-grass prairie. Ecology 71:1959–1967.

With, K.A. 2010. McCown’s longspur (Rhynchophanes mccownii). In: A. Poole (ed.) The birds of North America [online], Cornell Lab of Ornithology, Ithaca, NY. https://birdsna.org/Species-Account/bna/home.

Additional References

Augustine, D.J., J. Derner, D. Milchunas, D. Blumenthal, and L. Porensky. 2017. Grazing moderates increases in C3 grass abundance over seven decades across a soil texture gradient in shortgrass steppe. Journal of Vegetation Science, Doi:10.1111/jvs.12508, International Association of Vegetative Science

Augustine, D.J., J. Derner, J.K. Detling. 2014. Testing for thresholds in a semiarid grassland: The influence of prairie dogs and plague. Rangeland Ecology & Management 67(6)

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.

Collins, S. and S. Barber. (1985). Effects of disturbance on diversity in mixed-grass prairie. Vegetatio, 64, 87-94.

Cooperative climatological data summaries. NOAA. Western Regional Climate Center: Reno, NV. Web. Available online. http://www.wrcc.dri.edu/climatedata/climsum. Accessed 16 November, 2017.

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

Guyette, Richard P., M.C. Stambaugh, D.C. Dey, RM Muzika. (2012). Predicting fire frequency with chemistry and climate. Ecosystems, 15: 322-335.

Hart, R. and J. Hart. 1997. Rangelands of the Great Plains before European Settlement. Rangelands, 19(1), 4-11.

Hart, R. 2001. Plant biodiversity on shortgrass steppe after 55 years of zero, light, moderate, or heavy cattle grazing. Plant Ecology, 155, 111-118.

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.

Mack, Richard N., and J.N. Thompson. 1982. Evolution in Steppe with Few Large, Hooved Mammals. The American Naturalist. 119, No. 6, 757-773

Reyes-Fox, M., Stelzer H., Trlica M.J., McMaster, G.S., Andales, A.A., LeCain, D.R., and Morgan J.A. 2014. Elevated CO2 further lengthens growing season under warming conditions. Nature, April 23, 2014 issue. Available online. http://www.nature.com/nature/journal/v510/n7504/full/nature13207.html. Accessed 1 March, 2017.

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.

Stahl, David W., E.R. Cook, M.K. Cleaveland, M.D. Therrell, D.M. Meko, H.D. Grissino-Mayer, E. Watson, and B.H. Luckman. Tree-ring data document 16th century megadrought over North America. 2000. Eos, 81(12), 121-125.

Stewart, Omer C., 2002. Forgotten Fires. Univ. of Oklahoma Press, Publishing Division: Norman, OK.

Zelikova, Tamara Jane, D.M. Blumenthal, D.G. Williams, L. Souza, D.R. LeCain, J.Morgan. 2014. Long-term exposure to elevated CO2 enhances plant community stability by suppressing dominant plant species in a mixed-grass prairie. Ecology, 2014 issue at Available online. www.pnas.org/cgi/doi/10.1073/pnas.1414659111.

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. Available online. 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 1997, revised 2003. National Range and Pasture Handbook. Available online.
http://www.glti.nrcs.usda.gov/technical/publications/nrph.html. Accessed 26 February, 2018.

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

U.S. Dept. of Agriculture, Natural Resources Conservation Service. Web Soil Survey. Available online. http://websoilsurvey.sc.egov.usda.gov/App/WebSoilSurvey.aspx. Accessed 15 November, 2017.

Data collection for this ecological site was done in conjunction with the progressive soil surveys within the 67A Central High Plains (Northern Part) of Nebraska, Wyoming, and Colorado. It has been mapped and correlated with soils in the following soil surveys:

U.S. Dept. of Agriculture.1994. Soil Survey of Banner County, Nebraska.

U.S. Dept. of Agriculture. 1997. Soil Survey of Cheyenne County, Nebraska.

U.S. Dept. of Agriculture. 1999. Soil Survey of Garden County, Nebraska.

U.S. Dept. of Agriculture. 2005. Soil Survey of Kimball County, Nebraska.

U.S. Dept. of Agriculture. 1985. Soil Survey of Morrill County, Nebraska.

U.S. Dept. of Agriculture. 1968 Soil Survey of Scotts Bluff County, Nebraska.

U.S. Dept. of Agriculture.2013. Soil Survey of Scotts Bluff National Monument, Nebraska.

U.S. Dept. of Agriculture. 1998. Soil Survey of Sioux County, Nebraska.

U.S. Dept. of Agriculture. 1981. Soil Survey of Goshen County, Northern Part, Wyoming.

U.S. Dept. of Agriculture. 1971. Soil Survey of Goshen County, Southern Part, Wyoming.

U.S. Dept. of Agriculture. 1983. Soil Survey of Laramie County, Eastern Part, Wyoming.

U.S. Dept. of Agriculture. 2001. Soil Survey of Laramie County, Western Part, Wyoming.

U.S. Dept. of Agriculture. 2003. Soil Survey of Platte County, Wyoming.

U.S. Dept. of Agriculture. 1982. Soil Survey of Weld County, Northern Part, Colorado.
For manuscripts of archived soil surveys, see: https://websoilsurvey.nrcs.usda.gov/app/WebSoilSurvey.aspx.

Contributors

Kimberly Diller, Ecological Site Specialist, NRCS MLRA SSO, Pueblo CO
Andy Steinert, MLRA 67B Soil Survey Leader, NRCS MLRA SSO, Fort Morgan, CO
Doug Whisenhunt, Ecological Site Specialist, NRCS MLRA SSO, Pueblo CO

Approval

Kirt Walstad, 9/07/2023

Acknowledgments

Partners/Contributors:
David Cook, Rangeland Management Specialist, NRCS, Oshkosh, NE
George Gamblin, Rangeland Management Specialist, NRCS, Wheatland, WY
Cameron Clark, Resource Soil Scientist, NRCS, Douglas, WY
Angie Elg, Resource Soil Scientist, NRCS, Scottsbluff, NE
Tim Becket, Area Resource Conservationist, Douglas, WY
Mitchell Stephenson, Ph.D. Rangeland Management Specialist, UNL-Panhandle Research Station, Scottsbluff, NE
Kristin Dickinson, District Conservationist, NRCS, Sidney, NE
Rick Peterson, Ecological Site Inventory Specialist, SD-NRCS-MLRA SSO, Rapid City, SD

Program Support:
Nadine Bishop, NE State Rangeland Management Specialist/ QC, NRCS, Imperial, NE
John Hartung WY State Rangeland Management Specialist/ QC, NRCS, Casper, WY
David Kraft, NRCS MLRA Ecological Site Specialist-QA, Emporia, KS
James Bauchert, WY State Soil Scientist, WY-NRCS, Casper, WY
Neil Dominy, NE State Soil Scientist, NRCS, Lincoln, NE
Britt Weiser, NE State Resource Conservationist, NRCS, Lincoln, NE
Clayton Schmitz, WY State Resource Conservationist, NRCS, Casper, WY
Carla Green Adams, Editor, NRCS-SSR5, Denver, CO
Chad Remley, Regional Director, Northern Great Plains Soil Survey, Salina, KS
Those involved in developing the 2008 version: Chuck Ring, Rangeland Management Specialist, WY-NRCS, and Everett Bainter, WY State Rangeland Management Specialist, WY-NRCS

Non-discrimination statement
In accordance with Federal civil rights law and U.S. Department of Agriculture (USDA) civil rights regulations and policies, the USDA, its Agencies, offices, and employees, and institutions participating in or administering USDA programs are prohibited from discriminating based on race, color, national origin, religion, sex, gender identity (including gender expression), sexual orientation, disability, age, marital status, family/parental status, income derived from a public assistance program, political beliefs, or reprisal or retaliation for prior civil rights activity, in any program or activity conducted or funded by USDA (not all bases apply to all programs). Remedies and complaint filing deadlines vary by program or incident.

Persons with disabilities who require alternative means of communication for program information (e.g., Braille, large print, audiotape, American Sign Language, etc.) should contact the responsible Agency or USDA's TARGET Center at (202) 720-2600 (voice and TTY) or contact USDA through the Federal Relay Service at (800) 877-8339. Additionally, program information may be made available in languages other than English.

To file a program discrimination complaint, complete the USDA Program Discrimination Complaint Form, AD-3027, found online at How to File a Program Discrimination Complaint and at any USDA office or write a letter addressed to USDA and provide in the letter all of the information requested in the form. To request a copy of the complaint form, call (866) 632-9992. Submit your completed form or letter to USDA by: (1) mail: U.S. Department of Agriculture, Office of the Assistant Secretary for Civil Rights, 1400 Independence Avenue, SW, Washington, D.C. 20250-9410; (2) fax: (202) 690-7442; or (3) email:
program.intake@usda.gov.

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)	Dave Cook, Kristin Dickinson, George Gamblin, John Hartung, Andy Steinert, Nadine Bishop
Contact for lead author
Date	11/23/2020
Approved by	Kirt Walstad
Approval date
Composition (Indicators 10 and 12) based on	Annual Production

Indicators

Number and extent of rills:
None. Rills are not expected on this site.
Presence of water flow patterns:
Water flow patterns are not expected on more level terrain. Water flow patterns are present on steeper slopes ( greater than 30 percent) increasing with steeper slopes. Debris dams will be present in association with the waterflow patterns.
Number and height of erosional pedestals or terracettes:
Pedestalled plants and terracettes are not expected until slopes exceed 30 percent, becoming more evident as slopes increase.
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
Bare ground is typically 5 percent or less. This site can include a large amount of cobbles and gravel which are not considered to be bare ground.
Number of gullies and erosion associated with gullies:
None. Gullies should not be present on this site.
Extent of wind scoured, blowouts and/or depositional areas:
None. Wind-scoured and depositional areas are not present on the site.
Amount of litter movement (describe size and distance expected to travel):
On gentle slopes litter movement is not expected. As slopes increase fine litter may move short distances. When slopes exceed 30 percent, litter movement is expected and increases as slopes increase.
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
Soil stability ratings are typically 3 to 4.
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Soil surface layer ranges from 2 to 7 inches (5-17.75 cm) thick. Exposed areas of gravel are inherent to the site.

Soil colors vary from gray, brown, grayish brown, to light brown (values of 5 to 6) when dry and very dark grayish brown, dark grayish brown, or dark brown (values of 3 to 4) when moist.

Soil surface structure is typically granular, and below the surface is typically single grain.
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
The functional/structural groups provide a combination of rooting depths and structure which positively influences infiltration. Combination of shallow and deep rooted species (mid & tall rhizomatous and tufted perennial cool season grasses) with fine and coarse roots positively influences infiltration.

The expected composition of the plant community is 75 to 85 percent perennial grasses and grass-likes, 15 to 20 percent forbs, and 0 to 5 percent shrubs. The grass and grass-like component is made up of warm-season tall and mid-grasses (20 to 40 percent); cool-season, bunch grasses (10 to 30 percent); cool-season, rhizomatous grasses (2 to 10 percent), warm-season short grasses (10 to 15 percent); and grass-likes (3 to 5 percent).
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
None. A compaction layer is not expected on this site.
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:
1. Native, C4, tall and mid-grasses – 160-320 #/ac (20-40%), 2 species minimum

Sub-dominant:
2. Native, C3, bunch grasses – 80-240 #/ac (10-30%), 2 species minimum
3. Native, Perennial and Annual Forbs – 80-160 #/ac (10-15%), 5 species minimum
4. Native, C4 short grasses - 80-120 #/ac (10-15%), 1 species minimum

Other:
5. MInor: Native, C3, rhizomatous grasses - 28-80 (2-10%)
6. Minor: Grass-likes – 24-40 #/ac (3-5%)
7. Minor: Shrubs, Vines, Cacti – 8-24 #/ac: (1-3%)

Additional:
12a. Relative Dominance:
Community 1.1: Native, C4, tall and mid-grasses > Native, C3 bunch grasses > Native, C4, short grasses = Native, Perennial and Annual Forbs > Native, C3, rhizomatous grasses > Grass-likes > Shrubs, vines, cacti.

12b. F/S Groups not expected for the site: Introduced annual grasses, perennial introduced and naturalized grasses, trees.

12c. Number of F/S Groups: 7

12d. Species number in Dominant and Sub-dominant F/S Groups: 10
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
Some plant mortality and decadence is expected
Average percent litter cover (%) and depth ( in):
Plant litter cover is evenly distributed throughout the site and is expected to be 30 to 50 percent. Litter depth is approximately 0.25 inches (0.65 cm).
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
Annual production ranges from 550 to 1,100 pounds per acres (air dry basis). Average annual production is 800 pounds per acre under normal precipitation and weather conditions.
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:
Annual bromes, common mullein, broom snakeweed, fringed sagewort, pricklypear, burningbush, and Russian thistle, and others as they become known.

See:
Colorado Department of Agriculture Invasive Species Website:
https://www.colorado.gov/pacific/agconservation/noxious-weed-species
Wyoming Weed and Pest Council Website: https://wyoweed.org/
Nebraska Invasive Species website: https://neinvasives.com/plants.
Perennial plant reproductive capability:
All perennial species exhibit high vigor relative to recent weather conditions. Perennial grasses should have vigorous rhizomes or tillers; vegetative and reproductive structures are not stunted. All perennial species should be capable of reproducing annually.