Natural Resources
Conservation Service
Ecological site R035XD401AZ
Breaks 7-11" p.z.
Accessed: 12/22/2024
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.
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): 035X–Colorado Plateau
AZ CRA 35.4 – Colorado Plateau Cold Sagebrush – Grasslands
Elevations range from 4200 to 5100 feet and precipitation averages 7 to 11 inches. Vegetation includes winterfat, fourwing saltbush, buckwheat species, needlegrass, bottlebrush squirreltail, Indian ricegrass, black grama, blue grama, sideoats grama, gyp dropseed, and galleta. The soil temperature regime is mesic and the soil moisture regime is typic aridic. This unit occurs within the Colorado Plateau Physiographic Province and is characterized by a sequence of flat to gently dipping sedimentary rocks eroded into plateaus, valleys and deep canyons. Sedimentary rock classes dominate the plateau with volcanic fields occurring for the most part near its margin.
Table 1. Dominant plant species
| Tree |
Not specified |
|---|---|
| Shrub |
(1) Eriogonum umbellatum |
| Herbaceous |
(1) Hesperostipa comata ssp. comata |
Physiographic features
This site occurs on steep canyon walls and sides of plateaus and mesas. It typically suffers from excessive runoff from the steep slopes.
Table 2. Representative physiographic features
| Landforms |
(1)
Canyon
(2) Valley side |
|---|---|
| Flooding frequency | None |
| Ponding frequency | None |
| Elevation | 4,800 – 5,300 ft |
| Slope | 30 – 70% |
| Aspect | Aspect is not a significant factor |
Climatic features
Winter-Summer moisture ratios are typically 70:30 on the west side of this LRU and shift to 60:40 on the east side. Late spring is usually the driest period, and early fall moisture can be sporadic. Summer rains fall June-September; moisture originates in the Gulf of Mexico and creates convective, usually brief, intense thunderstorms. Cool season moisture October-May tends to be frontal; it originates in the Pacific and the Gulf of California and falls in widespread storms with longer duration and lower intensity. Precipitation generally comes as snow December-February. Accumulations above 10 inches are not common, but can occur. Snow usually lasts 3-4 days, but can persist much longer. Summer daytime temperatures are commonly 95-100 F and, on occasion, exceed 105F. Winter air temperatures can regularly go below 15 F and have been recorded below -15 F.
Table 3. Representative climatic features
| Frost-free period (average) | 220 days |
|---|---|
| Freeze-free period (average) | 150 days |
| Precipitation total (average) | 11 in |
Figure 2. Monthly precipitation range
Figure 3. Monthly average minimum and maximum temperature
Influencing water features
Soil features
The soils on this site occur as steep canyon walls, the sides of plateaus, mesas, hills and on escarpments. It typically suffers from excessive drainage. Complex geology and topography has created a multitude of soil textures, depths and developments. There are areas of exposed sandstone, shale and mudstone.
Typical taxonomic units in this site include:
SSA 623 Shivwits Area - MU 10 Berzatic family;
SSA 625 Mohave County NE Part - MU 64 a reference pedon for torriorthents.
Table 4. Representative soil features
| Parent material |
(1)
Colluvium
–
sandstone and shale
|
|---|---|
| Surface texture |
(1) Extremely cobbly loam (2) Extremely cobbly sandy loam (3) Very bouldery sandy loam |
| Family particle size |
(1) Loamy |
| Drainage class | Well drained to somewhat excessively drained |
| Permeability class | Very slow to very rapid |
| Soil depth | 5 – 60 in |
| Surface fragment cover <=3" | 15 – 50% |
| Surface fragment cover >3" | 5 – 20% |
| Available water capacity (0-40in) |
7 in |
| Calcium carbonate equivalent (0-40in) |
5 – 20% |
| Electrical conductivity (0-40in) |
2 mmhos/cm |
| Sodium adsorption ratio (0-40in) |
5 |
| Soil reaction (1:1 water) (0-40in) |
7.4 – 9 |
| Subsurface fragment volume <=3" (Depth not specified) |
5 – 40% |
| Subsurface fragment volume >3" (Depth not specified) |
5 – 10% |
Ecological dynamics
The plant communities found on an ecological site are naturally variable. Composition and production will vary with yearly conditions, location, aspect, and the natural variability of the soils. The historical climax plant community represents the natural potential plant communities found on relict or relatively undisturbed sites. Other plant communities described here represent plant communities that are known to occur when the site is disturbed by factors such as grazing, fire, or drought.
Production data provided in this site description is standardized to air-dry weight at the end of the summer growing season. The plant communities described in this site description are based on near normal rainfall years.
NRCS uses a Similarity Index to compare existing plant communities to the plant communities described here. Similarity Index is determined by comparing the production and composition of a plant community to the production and composition of a plant community described in this site description. To determine Similarity Index, compare the production (air-dry weight) of each species to that shown in the plant community description. For each species, count no more than the maximum amount shown for the species, and for each group, count no more than the maximum shown for the group. Divide the resulting total by the total normal year production shown in the plant community description. If rainfall has been significantly above or below normal, use the total production shown for above or below normal years. If field data is not collected at the end of the summer growing season, then the field data must be corrected to the end of the year production before comparing it to the site description. The growth curve can be used as a guide for estimating production at the end of the summer growing season.
State and transition model
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Ecosystem states
State 1 submodel, plant communities
State 1
Historic Climax Plant Community
Community 1.1
Historic Climax Plant Community
The dominant aspect of this site is a cold desert shrub/grassland. The site is on escarpments on the Moenkopi formation below the Shinarump formation. Due to steep slopes access for livestock is severely limited.
Figure 4. 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) |
|---|---|---|---|
| Shrub/Vine | 120 | 140 | 160 |
| Grass/Grasslike | 20 | 50 | 80 |
| Forb | 5 | 25 | 40 |
| Tree | 4 | 7 | 10 |
| Total | 149 | 222 | 290 |
Table 6. Ground cover
| Tree foliar cover | 0-1% |
|---|---|
| Shrub/vine/liana foliar cover | 0-5% |
| Grass/grasslike foliar cover | 0-1% |
| Forb foliar cover | 0% |
| Non-vascular plants | 0% |
| Biological crusts | 0% |
| Litter | 0% |
| Surface fragments >0.25" and <=3" | 0% |
| Surface fragments >3" | 0% |
| Bedrock | 0% |
| Water | 0% |
| Bare ground | 0% |
Table 7. Canopy structure (% cover)
| Height Above Ground (ft) | Tree | Shrub/Vine | Grass/ Grasslike |
Forb |
|---|---|---|---|---|
| <0.5 | – | – | – | – |
| >0.5 <= 1 | – | – | – | 0-1% |
| >1 <= 2 | – | – | 0-1% | – |
| >2 <= 4.5 | – | 0-5% | – | – |
| >4.5 <= 13 | 0-1% | – | – | – |
| >13 <= 40 | – | – | – | – |
| >40 <= 80 | – | – | – | – |
| >80 <= 120 | – | – | – | – |
| >120 | – | – | – | – |
Figure 5. Plant community growth curve (percent production by month). AZ0005, 35.4 7-11" p.z. Indian ricegrass. Most growth occurs in the spring, some growth occurs in the fall..
| 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 | 10 | 40 | 40 | 0 | 0 | 0 | 5 | 5 | 0 | 0 |
Figure 6. Plant community growth curve (percent production by month). AZ3541, 35.4 7-11" p.z. all sites. Most growth occurs in the spring and during the summer rainy season..
| 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 | 1 | 9 | 20 | 15 | 5 | 16 | 25 | 6 | 2 | 1 | 0 |
Figure 7. Plant community growth curve (percent production by month). AZ3542, 35.4 7-11" p.z. Needle and thread. Growth occurs mostly in the spring..
| 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 | 15 | 60 | 20 | 5 | 0 | 0 | 0 | 0 | 0 | 0 |
Figure 8. Plant community growth curve (percent production by month). AZ0001, 35.4 7-11" p.z. galleta. Growth begins in the spring, most growth occurs during the summer rainy season..
| 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 | 3 | 15 | 5 | 25 | 40 | 10 | 2 | 0 | 0 |
Additional community tables
Table 8. Community 1.1 plant community composition
| Group | Common name | Symbol | Scientific name | Annual production (lb/acre) | Foliar cover (%) | |
|---|---|---|---|---|---|---|
|
Tree
|
||||||
| 1 | Trees | 4–10 | ||||
| Utah juniper | JUOS | Juniperus osteosperma | 2–10 | – | ||
| twoneedle pinyon | PIED | Pinus edulis | 2–10 | – | ||
|
Shrub/Vine
|
||||||
| 2 | 120–150 | |||||
| sulphur-flower buckwheat | ERUM | Eriogonum umbellatum | 20–30 | – | ||
| skunkbush sumac | RHTR | Rhus trilobata | 10–30 | – | ||
| Apache plume | FAPA | Fallugia paradoxa | 10–20 | – | ||
| mormon tea | EPVI | Ephedra viridis | 10–20 | – | ||
| rubber rabbitbrush | ERNAG | Ericameria nauseosa ssp. nauseosa var. glabrata | 10–20 | – | ||
| broom snakeweed | GUSA2 | Gutierrezia sarothrae | 10–16 | – | ||
| Bigelow sage | ARBI3 | Artemisia bigelovii | 2–10 | – | ||
| yellow rabbitbrush | CHVI8 | Chrysothamnus viscidiflorus | 4–8 | – | ||
| Mexican cliffrose | PUME | Purshia mexicana | 0–6 | – | ||
| banana yucca | YUBA | Yucca baccata | 0–2 | – | ||
| Utah serviceberry | AMUT | Amelanchier utahensis | 0–2 | – | ||
| Nevada jointfir | EPNE | Ephedra nevadensis | 0–2 | – | ||
| Torrey's jointfir | EPTO | Ephedra torreyana | 0–2 | – | ||
| 4 | Other Shrubs | 0–10 | ||||
| Shrub (>.5m) | 2SHRUB | Shrub (>.5m) | 0–10 | – | ||
| Wyoming big sagebrush | ARTRW8 | Artemisia tridentata ssp. wyomingensis | 0–10 | – | ||
| fourwing saltbush | ATCA2 | Atriplex canescens | 0–10 | – | ||
| Eastern Mojave buckwheat | ERFA2 | Eriogonum fasciculatum | 0–10 | – | ||
| water jacket | LYAN | Lycium andersonii | 0–10 | – | ||
| Sonoran scrub oak | QUTU2 | Quercus turbinella | 0–10 | – | ||
| Mojave sage | SAMO3 | Salvia mohavensis | 0–10 | – | ||
| twistspine pricklypear | OPMA2 | Opuntia macrorhiza | 0–2 | – | ||
|
Grass/Grasslike
|
||||||
| 3 | 20–60 | |||||
| needle and thread | HECOC8 | Hesperostipa comata ssp. comata | 10–30 | – | ||
| James' galleta | PLJA | Pleuraphis jamesii | 10–16 | – | ||
| Indian ricegrass | ACHY | Achnatherum hymenoides | 6–12 | – | ||
| desert needlegrass | ACSP12 | Achnatherum speciosum | 0–2 | – | ||
| squirreltail | ELELE | Elymus elymoides ssp. elymoides | 0–2 | – | ||
| 1 | Other Perennial Grasses | 0–4 | ||||
| Grass, perennial | 2GP | Grass, perennial | 0–4 | – | ||
| threeawn | ARIST | Aristida | 0–4 | – | ||
| sideoats grama | BOCU | Bouteloua curtipendula | 0–4 | – | ||
| black grama | BOER4 | Bouteloua eriopoda | 0–4 | – | ||
| prairie Junegrass | KOMA | Koeleria macrantha | 0–4 | – | ||
|
Forb
|
||||||
| 4 | 8–32 | |||||
| princesplume | STANL | Stanleya | 6–14 | – | ||
| white sagebrush | ARLU | Artemisia ludoviciana | 0–4 | – | ||
| Brenda's yellow cryptantha | CRFL5 | Cryptantha flava | 2–4 | – | ||
| flatcrown buckwheat | ERDE6 | Eriogonum deflexum | 2–4 | – | ||
| desert trumpet | ERIN4 | Eriogonum inflatum | 0–4 | – | ||
| whitestem blazingstar | MEAL6 | Mentzelia albicaulis | 0–4 | – | ||
| 2 | Other Perennial Forbs | 2–4 | ||||
| Forb, perennial | 2FP | Forb, perennial | 2–4 | – | ||
| brownfoot | ACWR5 | Acourtia wrightii | 2–4 | – | ||
| buckwheat | ERIOG | Eriogonum | 2–4 | – | ||
| fineleaf hymenopappus | HYFI | Hymenopappus filifolius | 2–4 | – | ||
| beardtongue | PENST | Penstemon | 2–4 | – | ||
| rock goldenrod | PEPU7 | Petradoria pumila | 2–4 | – | ||
| spiny phlox | PHHO | Phlox hoodii | 2–4 | – | ||
| 3 | Other Annual Forbs | 2–6 | ||||
| Forb, annual | 2FA | Forb, annual | 2–6 | – | ||
| milkvetch | ASTRA | Astragalus | 2–6 | – | ||
| borage | BORAG | Borago | 2–6 | – | ||
| sacred thorn-apple | DAWR2 | Datura wrightii | 2–6 | – | ||
| spurge | EUPHO | Euphorbia | 2–6 | – | ||
| gilia | GILIA | Gilia | 2–6 | – | ||
| desert tobacco | NIOBO | Nicotiana obtusifolia var. obtusifolia | 2–6 | – | ||
| phacelia | PHACE | Phacelia | 2–6 | – | ||
| primrose | PRIMU | Primula | 2–6 | – | ||
Interpretations
Animal community
This site is not suitable for grazing by livestock due to the steep topography and limited forage production. Access is severely limited by slope and a cover of cobbles and boulders. Erosion hazard is high because of sparse vegetation, steep slopes and rapid runoff.
There is relatively poor diversity within the plant community of this site. Because of the grass component, the site is dominated by grassland wildlife species. However, the site is transitory to almost all species due to lack of available water.
Recreational uses
Steepness of slope and ruggedness of the surface terrain limits recreation use to mainly hiking, wildlife viewing, and photography.
Winters are cold, however, relatively mild spring, fall and summer months are attractive to recreationists.
Wildlife most likely to be found on the site are; Black-tailed jackrabbit, cottontail rabbit, antelope squirrel, deer mouse, coyote, western rattlesnake, gopher snake, black-collared lizard, longnose leopard lizard, short-horned lizard, red tailed hawk, and ravens.
Supporting information
Type locality
| Location 1: Mohave County, AZ | |
|---|---|
| Township/Range/Section | T33N R10W S2 |
| General legal description | Two possible locations: Coconino County - about 7 miles east of Colorado City - Section 5, T41N, R5W; Mohave County - Trail Canyon about 1 mile North of Parashant Canyon - Section 2, T33N, R10W. |
Contributors
Larry D. Ellicott
Steve Barker
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) | |
|---|---|
| Contact for lead author | |
| Date | |
| Approved by | |
| Approval date | |
| Composition (Indicators 10 and 12) based on | Annual Production |
Indicators
-
Number and extent of rills:
-
Presence of water flow patterns:
-
Number and height of erosional pedestals or terracettes:
-
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
-
Number of gullies and erosion associated with gullies:
-
Extent of wind scoured, blowouts and/or depositional areas:
-
Amount of litter movement (describe size and distance expected to travel):
-
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
-
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
-
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
-
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction 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:
Sub-dominant:
Other:
Additional:
-
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
-
Average percent litter cover (%) and depth ( in):
-
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
-
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:
-
Perennial plant reproductive capability:
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