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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): 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.Classification relationships
Aspect Differences Near CRA Boundaries:
Hot south and West slopes at lower elevations may more closely resemble the thermic site D30-2 Breaks 9-12" p.z., and production will be segnificantly lower at all elevations. Cooler north and east slopes are more productive, and at higher elevations will more closely resemble D35-3 Breaks 10-14" p.z.Associated sites
R035XD404AZ Gypsum Hills 7-11" p.z.
Gypsum Hills (035XD404AZ)
R035XD405AZ Gypsum Upland 7-11" p.z.
Gypsum Upland (035XD405AZ)
R035XD414AZ Sandy Loam Upland 7-11" p.z.
Shallow Loamy (035XD414AZ)
Table 1. Dominant plant species
Tree Not specified
Shrub (1) Ephedra viridis
(2) Fallugia paradoxaHerbaceous (1) Achnatherum speciosum
(2) Achnatherum aridumPhysiographic features
This desert shrub-grassland site occurs in an upland position. Drainages between the hills derive some benefit from run-on moisture, but most of the site has excessive run-off because of rock outcrop and steep colluvial slopes.
Table 2. Representative physiographic features
Landforms (1) Escarpment
Flooding frequency None Ponding frequency None Elevation 4100 – 5300 ft Slope 35 – 100 % Aspect N, NE 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) 10 in BarLineFigure 2. Monthly precipitation range
BarLineFigure 3. Monthly average minimum and maximum temperature
">Influencing water features
Soil features
Soil moisture regime is typic aridic. Temperature regime is mesic. Soils are well-drained with sandy loam and fine sandy loam textures that are occasionally gravelly. Subsurface textures are sandy loam and fine sandy loam. Water erosion hazard is very severe due to slopes. Wind erosion is slight to high. Plant-soil moisture relationship is poor due to shallow and very shallow soils combined with gypsum content.
Typical taxonomic unit is:
SSA623 Shivwits Area - MU 10 Goblin.Table 4. Representative soil features
Parent material (1) Alluvium – sandstone and shale
Surface texture (1) Gravelly sandy loam
(2) Fine sandy loam
(3) Loam
Family particle size (1) Loamy
Drainage class Well drained Permeability class Moderately rapid Soil depth 6 – 12 in Surface fragment cover <=3" 0 – 15 % Surface fragment cover >3" 0 – 1 % Available water capacity
(0-40in)0.3 – 0.6 in Calcium carbonate equivalent
(0-40in)5 – 10 % Electrical conductivity
(0-40in)2 – 4 mmhos/cm Sodium adsorption ratio
(0-40in)0 – 5 Soil reaction (1:1 water)
(0-40in)7.4 – 7.8 Subsurface fragment volume <=3"
(Depth not specified)0 – 5 % Subsurface fragment volume >3"
(Depth not specified)0 – 1 % 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 fire, grazing, 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 amount shown for each group. Divide the resulting total by the total normal year production shown in the plant community description. If the rainfall has ben 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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Click on state and transition labels to scroll to the respective textEcosystem states
State 1 submodel, plant communities
State 1
Historic Climax Plant CommunityCommunity 1.1
Historic Climax Plant CommunityThe aspect of this site can be quite variable, driven by the influence on the soil of remnants of various geologic formations. A thin soil layer of colluvium from limestone and sandstone can result in patches (usually small) of a significant amount of perennial grasses and forbs, chiefly needlegrasses, black grama and Louisiana sagewort. On most of this site, the colluvial deposits have eroded away and the upper layers of the Moenkopi formation are exposed. Widely scattered desert shrubs, ephedra, Apache plume and rabbitbrush, are common, but small amounts of many different shrubs can be found. Perennial plant spacing varies from 0.75-4.0 feet.
Extreme slopes, generally wide plant spacing, rock outcrop, undeveloped soil and very limited livestock access indicate this sit is quite stable. Fire and grazing influences are not significant. Invading species are limited to small amounts of annuals such as cheatgrass brome. Geologic erosion can be quite high. Rock and talus slides are common.
Hot south and west slopes at lower elevations may more closely resemble the thermic site D30-2 Breaks 9-12" pz, and production will be significantly lower at all elevations. Cooler north and east slopes are more productive and at higher elevations will more closely resemble D35-3 Breaks 10-14" pz.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 90 150 210 Grass/Grasslike 75 113 150 Forb 6 14 21 Tree 0 2 3 Total 171 279 384 Table 6. Ground cover
Tree foliar cover 0-0% Shrub/vine/liana foliar cover 0-10% Grass/grasslike foliar cover 0-0% Forb foliar cover 0-0% Non-vascular plants 0% Biological crusts 0% Litter 10-20% Surface fragments >0.25" and <=3" 0-20% Surface fragments >3" 0% Bedrock 0% Water 0% Bare ground 70-80% Table 7. Canopy structure (% cover)
Height Above Ground (ft) Tree Shrub/Vine Grass/
GrasslikeForb <0.5 – – – 0-1% >0.5 <= 1 – – 0-1% – >1 <= 2 – – 0-1% – >2 <= 4.5 – 2-8% – – >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). AZ3570 , 35.4 7-11" p.z. Nevada Mormon tea. Growth occurs mostly in spring and early summer using stored winter moisture..
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec J F M A M J J A S O N D 0 0 5 25 25 20 15 10 0 0 0 0 Figure 9. Plant community growth curve (percent production by month). AZ5215 , 35.4 7-11" p.z. black grama. Growth occurs mostly 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 0 5 5 30 50 10 0 0 0 Additional community tables
Table 8. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Grass/Grasslike0 50–150 Mormon needlegrass ACAR14 Achnatherum aridum 15–45 – desert needlegrass ACSP12 Achnatherum speciosum 15–45 – Indian ricegrass ACHY Achnatherum hymenoides 9–18 – needle and thread HECOC8 Hesperostipa comata ssp. comata 9–18 – spike dropseed SPCO4 Sporobolus contractus 6–15 – sand dropseed SPCR Sporobolus cryptandrus 6–15 – bush muhly MUPO2 Muhlenbergia porteri 0–9 – squirreltail ELELE Elymus elymoides ssp. elymoides 3–9 – prairie Junegrass KOMA Koeleria macrantha 0–6 – 1 25–75 black grama BOER4 Bouteloua eriopoda 6–18 – hairy woollygrass ERPI5 Erioneuron pilosum 6–15 – James' galleta PLJA Pleuraphis jamesii 3–15 – gyp dropseed SPNE Sporobolus nealleyi 6–15 – slim tridens TRMU Tridens muticus 6–15 – sideoats grama BOCU Bouteloua curtipendula 0–9 – 2 0–9 Grass, perennial 2GP Grass, perennial 0–9 – threeawn ARIST Aristida 0–9 – blue grama BOGR2 Bouteloua gracilis 0–9 – low woollygrass DAPU7 Dasyochloa pulchella 0–9 – wildrye ELYMU Elymus 0–9 – New Mexico muhly MUPA2 Muhlenbergia pauciflora 0–9 – burrograss SCBR2 Scleropogon brevifolius 0–9 – 3 0–6 hairy woollygrass ERPI5 Erioneuron pilosum 6–15 – spike dropseed SPCO4 Sporobolus contractus 6–15 – sand dropseed SPCR Sporobolus cryptandrus 6–15 – gyp dropseed SPNE Sporobolus nealleyi 6–15 – slim tridens TRMU Tridens muticus 6–15 – Grass, annual 2GA Grass, annual 0–6 – sixweeks grama BOBA2 Bouteloua barbata 0–6 – lovegrass ERAGR Eragrostis 0–6 – sixweeks fescue VUOC Vulpia octoflora 0–6 – Forb0 6–21 white sagebrush ARLU Artemisia ludoviciana 15–30 – fanleaf hawthorn CRFL Crataegus flabellata 3–9 – Colorado four o'clock MIMU Mirabilis multiflora 3–9 – little combseed PEPU Pectocarya pusilla 3–9 – Wright's cliffbrake PEWR Pellaea wrightiana 3–9 – phlox PHLOX Phlox 3–9 – globemallow SPHAE Sphaeralcea 3–9 – Forb, perennial 2FP Forb, perennial 3–9 – desert princesplume STPI Stanleya pinnata 0–6 – 4 0–6 James' galleta PLJA Pleuraphis jamesii 3–15 – Forb, annual 2FA Forb, annual 0–6 – aster ASTER Aster 0–6 – buckwheat ERIOG Eriogonum 0–6 – spurge EUPHO Euphorbia 0–6 – blazingstar MENTZ Mentzelia 0–6 – desert tobacco NIOBO Nicotiana obtusifolia var. obtusifolia 0–6 – primrose PRIMU Primula 0–6 – Shrub/Vine13 6–24 Apache plume FAPA Fallugia paradoxa 6–24 – squirreltail ELELE Elymus elymoides ssp. elymoides 3–9 – 14 6–15 fourwing saltbush ATCA2 Atriplex canescens 6–15 – yellow rabbitbrush CHVI8 Chrysothamnus viscidiflorus 6–15 – rockjasmine buckwheat ERAN5 Eriogonum androsaceum 6–15 – 15 6–12 broom snakeweed GUSA2 Gutierrezia sarothrae 6–12 – 16 30–60 Torrey's jointfir EPTO Ephedra torreyana 30–60 – mormon tea EPVI Ephedra viridis 30–60 – globemallow SPHAE Sphaeralcea 3–9 – 17 0–9 white sagebrush ARLU Artemisia ludoviciana 15–30 – banana yucca YUBA Yucca baccata 0–9 – 18 3–9 purple coneflower ECHIN Echinacea 3–9 – plains pricklypear OPPO Opuntia polyacantha 3–9 – 19 9–21 Fremont's mahonia MAFR3 Mahonia fremontii 9–21 – skunkbush sumac RHTR Rhus trilobata 9–21 – 20 0–15 Bigelow sage ARBI3 Artemisia bigelovii 0–15 – black sagebrush ARNO4 Artemisia nova 0–15 – 21 6–18 buckwheat ERIOG Eriogonum 6–18 – 22 6–21 Indian mallow ABUTI Abutilon 6–21 – Wright's beebrush ALWR Aloysia wrightii 6–21 – Utah serviceberry AMUT Amelanchier utahensis 6–21 – Wyoming big sagebrush ARTRW8 Artemisia tridentata ssp. wyomingensis 6–21 – brickellbush BRICK Brickellia 6–21 – desert sweet CHMI2 Chamaebatiaria millefolium 6–21 – button brittlebush ENFR Encelia frutescens 6–21 – spiny hopsage GRSP Grayia spinosa 6–21 – false broomweed HAPLO Haploesthes 6–21 – winterfat KRLA2 Krascheninnikovia lanata 6–21 – water jacket LYAN Lycium andersonii 6–21 – pricklypear OPUNT Opuntia 6–21 – mariola PAIN2 Parthenium incanum 6–21 – Fremont's dalea PSFRF Psorothamnus fremontii var. fremontii 6–21 – Mexican cliffrose PUME Purshia mexicana 6–21 – snowberry SYMPH Symphoricarpos 6–21 – threefold TRIXI Trixis 6–21 – Tree23 0–3 singleleaf ash FRAN2 Fraxinus anomala 0–3 – Utah juniper JUOS Juniperus osteosperma 0–3 – Interpretations
Animal community
Very steep slopes and rock outcrops are very limiting to livestock use.
This site is typically a travel corridor for game animals such as deer, and is also used to some extent by jackrabbits. This site rarely receives significant negative impact from other uses and management potential for wildlife is minimal.
Potential species present include the great horned owl, golden eagle, rock wren, collared lizard, Mexican free-tailed bat, coyote, white-throated antelope squirrel, red-tailed hawk, common raven, gopher snake, leopard lizard, deer mouse, black-tailed jackrabbit,, peregrine falcon, horned lark, Western rattlesnake, Western pipistrelle, canyon mouse, rock squirrel migratory birds.Recreational uses
Hiking, hunting, wildlife observation and photography are the main recreational activities.
Other information
T&E Species: peregrine falcon (potential habitat)
Supporting information
Type locality
Location 1: Mohave County, AZ Township/Range/Section T38N R9W S4 General legal description Grandstand 7.5 minute Quad; along the Hurricane Cliffs about 1/2 mile south of the Navajo Trail; Section 4, T38N, R9W, Mohave County, AZ. Contributors
Larry D. Ellicott
S. Barker
Steve BarkerRangeland 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
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Number and extent of rills:
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Presence of water flow patterns:
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Number and height of erosional pedestals or terracettes:
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Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
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Number of gullies and erosion associated with gullies:
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Extent of wind scoured, blowouts and/or depositional areas:
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Amount of litter movement (describe size and distance expected to travel):
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Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
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Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
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Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
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Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
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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:
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Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
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Average percent litter cover (%) and depth ( in):
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Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
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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:
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Perennial plant reproductive capability:
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