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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
This ecological site occurs in Common Resource Area 35.2 - the Colorado Plateau Shrub – Grasslands
Elevations range from 3800-5800 feet and precipitation averages 6 to 10 inches per year. Vegetation includes shadscale, fourwing saltbush, Mormon tea, blackbrush, Indian ricegrass, galleta, blue grama, and black grama. 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.
Associated sites
R035XB206AZ Sandy Upland 6-10" p.z. Warm
Deep sandy sites that are calcareous and occur on uplands
R035XB230AZ Sandstone Upland 6-10" p.z. Very Shallow, Warm
Similar site that is predominantly soil covered, instead of predominantly bedrock outcrop. Very shallow soils formed in residuum and eolian deposits
Table 1. Dominant plant species
Tree Not specified
Shrub (1) Coleogyne ramosissima
(2) Purshia stansburianaHerbaceous (1) Achnatherum hymenoides
(2) Bouteloua eriopodaPhysiographic features
This site occurs on extensive relatively flat sandstone bedrock areas with widely scattered vegetation in shallow depressions and fractures in the bedrock. Slopes are generally less than 15 percent, but there can be steeper spots within the site.
This site occurs on summits and ledges of mesas, structural benches, dipslopes, cuestas and plateaus. It does not benefit from run-in moisture from adjacent areas and occurs on all exposures.Table 2. Representative physiographic features
Landforms (1) Structural bench
(2) Mesa
(3) Cuesta
Flooding frequency None Ponding frequency None Elevation 3800 – 5800 ft Slope 0 – 15 % Aspect Aspect is not a significant factor Climatic features
The 35.2 Colorado Plateau Cold Desert Shrub - Grassland common resource area has a very dry and windy climate that is hot in the summer and cold in the winter. The annual precipitation averages between 6 and 10 inches. The soil moisture regime is typic aridic and the soil temperature regime is mesic. A slight majority of the precipitation arrives during the late fall, winter, and early spring. This winter season moisture originates in the Pacific Ocean and arrives as rain, or sometimes snow, during widespread frontal storms of generally low intensity. The majority of the snow (average range of 1 to 17 inches) falls from December through February, but rarely lasts more than a few days. A seasonal drought occurs from late May through early July. Summer rains occur from July through September during brief intense local thunderstorms. The rain is sporadic in intensity and location. The moisture originates from the Gulf of Mexico in the early summer and the Gulf of California in the late summer/early fall. Windy conditions are common year round, but the winds are strongest and most frequent during the spring.
Table 3 Representative climatic features
Frost-free period (average) 180 days Freeze-free period (average) 210 days Precipitation total (average) 10 in BarLineFigure 2. Monthly precipitation range
BarLineFigure 3. Monthly average minimum and maximum temperature
">Influencing water features
This site is mostly bedrock. Most of the preciptiation falling on this site runs off the site and contributes moisture to other ecological sites. Some of the moisture is captured in depressions and cracks in the bedrocks where there is sufficient soil to support vegetation.
Soil features
Soils on this site are very shallow with little or no distinguishing soil development characteristics. Surface textures are sands to loamy sands with sandy subsurface textures. The soils are deposited and stabilized in shallow depression and/or in fractures of undulating exposed bedrock on sandstone.
Soil survey map unit components that have been correlated with this ecological site include:
SSA-711 Navajo Mountain Area 44, 45, 52-Rock outcrop
SSA-UT689 Glen Canyon Area 17-Needle;
Table 4. Representative soil features
Parent material (1) Eolian sands – calcareous sandstone
(2) Alluvium – sandstone
Surface texture (1) Sand
(2) Fine sand
(3) Loamy sand
Family particle size (1) Sandy
Drainage class Well drained to excessively drained Permeability class Moderate to rapid Soil depth 0 – 10 in Surface fragment cover <=3" 0 – 15 % Surface fragment cover >3" 0 – 60 % Available water capacity
(0-40in)0 – 0.9 in Calcium carbonate equivalent
(0-40in)Not specified Electrical conductivity
(0-40in)0 – 8 mmhos/cm Sodium adsorption ratio
(0-40in)Not specified Soil reaction (1:1 water)
(0-40in)7.4 – 8.4 Ecological dynamics
An ecological site is not a precise assemblage of species for which the proportions are the same from place to place or from year to year. In all plant communities, variability is apparent in productivity and occurrence of individual species. Spatial boundaries of the communities; however, can be recognized by characteristic patterns of species composition, association, and community structure. The historic climax plant community for this ecological site has been described by sampling relict or relatively undisturbed sites and/or reviewing historic records. The historic climax plant community is the plant community that evolved over time with the soil forming process and long term changes in climatic conditions of the area. It is the plant community that was best adapted to the unique combination of environmental factors associated with the site.
Natural disturbances, such as drought, fire, grazing of native fauna, and insects, are inherent in the development and maintenance of these plant communities. The effects of these disturbances are part of the range of characteristics of the ecological site. Fluctuations in plant community structure and function caused by the effects of natural disturbances help establish the boundaries and characteristics of an ecological site. They are accounted for as part of the range of characteristics of the ecological site. Recognizable plant community phases are identified in the reference state of the ecological site. Some sites may have a small range of variation, while others have a large range. Some plant community phases may exist for long periods of time, while others may only occur for a couple of years after a disturbance.
Deterioration of the plant community, hydrology, or soil site stability on an ecological site can result in crossing a threshold or potentially irreversible boundary to another state, or equilibrium. This can occur as a result of the loss of soil surface through erosion, the loss of the stability of the site due to disturbances that cause active erosion on the site, increases in the amounts and/or patterns or runoff from rainstorms, changes in availability of surface and subsurface water, significant changes in plant structural and functional types, or the introduction of non-native species. When these thresholds are crossed, the potential of the ecological site to return to the historic climax plant community can be lost, or restoration will require significant inputs . There may be multiple states possible for an ecological site, determined by the type and or severity of disturbance.
The known states and transition pathways for this ecological site are described in the state and transition model. Within each state, there may be one or more known plant community phases. These community phases describe the different plant community that can be recognized and mapped across this ecological site. The state and transition model is intended to help land users recognize the current plant community on the ecological site, and the management options for improving the plant community to the desired plant community.
Plant production information in this site description is standardized to the annual production on an air-dry weight basis in near normal rainfall years.
State and transition model
Custom diagramStandard diagram
Figure 4. State and Transition Model - R035XB255AZ
More interactive model formats are also available. View Interactive Models
More interactive model formats are also available. View Interactive Models
Click on state and transition labels to scroll to the respective textEcosystem states
State 1 submodel, plant communities
State 2 submodel, plant communities
State 1
Reference StateThis state has a variety of vegetation due to extra run-on moisture from adjacent rock outcrops, differences in aspect, temperature, and availability of seed sources. This site receives extra moisture in the form of runoff from the surrounding rock outcrop. This extra moisture results in variety of shrub and herbaceous species, and in some locations an occasional small tree. Plants commonly found on this site are blackbrush, Stanbury cliffrose, Bigelow sagebrush, Utah serviceberry, Indian ricegrass, black grama and galleta.
Sites with very shallow soils and depressions of deeper soils will be dominate by grasses, forbs and low growing shrubs with widely scattered large shrubs. On sites where deep fractures in the sandstone rock outcrop occur along with shallow soil depositions will have a mix of shrubs, grasses and forbs. These sites will also have scattered large shrubs and small trees where available moisture and deep fractures exist. These sites are relatively stable due to lack of fire and low potential from invasion of non-native species.Community 1.1
Low Shrub-Cliffrose and Perennial Grasses (HCPC)
Figure 5. Sandstone Rockland 6-10" p.z.
Figure 6. 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 45 70 85 Grass/Grasslike 20 35 55 Forb 2 5 12 Tree 0 5 10 Total 67 115 162 Table 6. Soil surface cover
Tree basal cover 0-0% Shrub/vine/liana basal cover 0-0% Grass/grasslike basal cover 0-0% Forb basal cover 0-0% Non-vascular plants 0-10% Biological crusts 0-10% Litter 0-10% Surface fragments >0.25" and <=3" 0% Surface fragments >3" 0% Bedrock 50-90% Water 0% Bare ground 10-30% Table 7. Canopy structure (% cover)
Height Above Ground (ft) Tree Shrub/Vine Grass/
GrasslikeForb <0.5 – 0-3% 0-3% 0-3% >0.5 <= 1 – 0-3% 0-3% 0-1% >1 <= 2 – 0-3% 0-2% 0-1% >2 <= 4.5 – 0-2% – – >4.5 <= 13 0-1% 0-1% – – >13 <= 40 – – – – >40 <= 80 – – – – >80 <= 120 – – – – >120 – – – – State 2
Introduction of Non-Native StateThis state has a variety of vegetation due to extra run-on moisture from adjacent rock outcrops, differences in aspect, temperature, and availability of seed sources. This site receives extra moisture in the form of runoff from the surrounding rock outcrop. This extra moisture results in variety of shrub and herbaceous species, and in some locations an occasional small tree. Plants commonly found on this site are blackbrush, Stanbury cliffrose, Bigelow sagebrush, Utah serviceberry, Indian ricegrass, black grama and galleta.
Sites with very shallow soils and depressions of deeper soils will be dominate by grasses, forbs and low growing shrubs with widely scattered large shrubs. On sites where deep fractures in the sandstone rock outcrop occur along with shallow soil depositions will have a mix of shrubs, grasses and forbs. These sites will also have scattered large shrubs and small trees where available moisture and deep fractures exist. These sites are relatively stable due to lack of fire. The plant communities in this state will have introduced annuals including cheatgrass, red brome and Russian thistle.Community 2.1
Low shrubs - Cliffrose/Perennial Grasses with Non-NativesThis community phase is similar to the historic climax plant community, but introduced annual grasses and forbs are present in the plant community and compete with native species.
Transition T1A
State 1 to 2Introduction of non-native species creates a irreversible change to the plant community.
Additional community tables
Table 8. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Grass/Grasslike1 Dominant Grasses 20–40 black grama BOER4 Bouteloua eriopoda 0–25 – Indian ricegrass ACHY Achnatherum hymenoides 0–20 – blue grama BOGR2 Bouteloua gracilis 0–15 – James' galleta PLJA Pleuraphis jamesii 0–15 – 2 Miscellaneous Grasses 0–15 Fendler's threeawn ARPUF Aristida purpurea var. fendleriana 0–10 – needle and thread HECOC8 Hesperostipa comata ssp. comata 0–10 – New Mexico feathergrass HENE5 Hesperostipa neomexicana 0–10 – sideoats grama BOCU Bouteloua curtipendula 0–5 – spike dropseed SPCO4 Sporobolus contractus 0–5 – sand dropseed SPCR Sporobolus cryptandrus 0–5 – saline wildrye LESAS Leymus salinus ssp. salinus 0–2 – muttongrass POFE Poa fendleriana 0–2 – Grass, annual 2GA Grass, annual 0–2 – Grass, perennial 2GP Grass, perennial 0–2 – Forb3 Forbs 1–10 globemallow SPHAE Sphaeralcea 0–5 – Wright's bird's beak COWR2 Cordylanthus wrightii 0–5 – gilia GILIA Gilia 0–3 – winged buckwheat ERAL4 Eriogonum alatum 0–2 – desert trumpet ERIN4 Eriogonum inflatum 0–2 – flatspine stickseed LAOC3 Lappula occidentalis 0–2 – Jones' pepperweed LEMOJ Lepidium montanum var. jonesii 0–2 – cryptantha CRYPT Cryptantha 0–2 – tansymustard DESCU Descurainia 0–2 – mustard BRASS2 Brassica 0–2 – Indian paintbrush CASTI2 Castilleja 0–2 – thrift mock goldenweed STARA Stenotus armerioides var. armerioides 0–2 – longbeak streptanthella STLO4 Streptanthella longirostris 0–2 – Townsend daisy TOWNS Townsendia 0–2 – rock goldenrod PEPUP Petradoria pumila ssp. pumila 0–2 – cleftleaf wildheliotrope PHCRC Phacelia crenulata var. corrugata 0–2 – phlox PHLOX Phlox 0–2 – fineleaf hymenopappus HYFI Hymenopappus filifolius 0–2 – dock RUMEX Rumex 0–2 – ragwort SENEC Senecio 0–2 – ipomopsis IPOMO2 Ipomopsis 0–1 – Newberry's twinpod PHNE5 Physaria newberryi 0–1 – woolly plantain PLPA2 Plantago patagonica 0–1 – whitemargin sandmat CHAL11 Chamaesyce albomarginata 0–1 – Fendler's sandmat CHFE3 Chamaesyce fendleri 0–1 – Parry's sandmat CHPA28 Chamaesyce parryi 0–1 – wedgeleaf draba DRCU Draba cuneifolia 0–1 – larkspur DELPH Delphinium 0–1 – bristle flax LIAR3 Linum aristatum 0–1 – hoary tansyaster MACA2 Machaeranthera canescens 0–1 – Colorado four o'clock MIMU Mirabilis multiflora 0–1 – beardtongue PENST Penstemon 0–1 – Wetherill's buckwheat ERWE Eriogonum wetherillii 0–1 – hairy false goldenaster HEVI4 Heterotheca villosa 0–1 – prickly sandwort ARAC2 Arenaria aculeata 0–1 – Shrub/Vine4 Dominant Shrubs 40–60 blackbrush CORA Coleogyne ramosissima 0–50 – Stansbury cliffrose PUST Purshia stansburiana 0–30 – Bigelow sage ARBI3 Artemisia bigelovii 0–20 – 5 Miscellaneous Shrubs 0–20 broom snakeweed GUSA2 Gutierrezia sarothrae 0–10 – Greene's rabbitbrush CHGR6 Chrysothamnus greenei 0–10 – Utah serviceberry AMUT Amelanchier utahensis 0–10 – shadscale saltbush ATCO Atriplex confertifolia 0–10 – skunkbush sumac RHTR Rhus trilobata 0–10 – roundleaf buffaloberry SHRO Shepherdia rotundifolia 0–5 – narrowleaf yucca YUAN2 Yucca angustissima 0–5 – Navajo yucca YUBA2 Yucca baileyi 0–5 – Sonoran scrub oak QUTU2 Quercus turbinella 0–5 – sand sagebrush ARFI2 Artemisia filifolia 0–5 – fourwing saltbush ATCA2 Atriplex canescens 0–5 – Cutler's jointfir EPCU Ephedra cutleri 0–5 – Torrey's jointfir EPTO Ephedra torreyana 0–5 – crispleaf buckwheat ERCO14 Eriogonum corymbosum 0–5 – rubber rabbitbrush ERNA10 Ericameria nauseosa 0–5 – singleleaf ash FRAN2 Fraxinus anomala 0–5 – plains pricklypear OPPO Opuntia polyacantha 0–2 – brickellbush BRICK Brickellia 0–2 – littleleaf mountain mahogany CEIN7 Cercocarpus intricatus 0–2 – alderleaf mountain mahogany CEMO2 Cercocarpus montanus 0–2 – Tree6 Trees 0–10 Utah juniper JUOS Juniperus osteosperma 0–6 – twoneedle pinyon PIED Pinus edulis 0–4 – Table 9. Community 2.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Interpretations
Animal community
This site is suitable for grazing during any period of the year by cows and calves, stocker cattle, sheep and horses. Prescribed grazing systems can benefit this site by allowing rest periods for the cool season species.
The potential plant community provides a variety of food and cover plants for wildlife. When the vegetation complex retrogresses then unpalatable shrub species increase and the site becomes less uasble as a foraging area for some species. Grazing practices that encourage cool season grass species are beneficial to antelope, cottontails, and rodents. Shrubs that provide both food and cover should be maintained.Recreational uses
Site is located on gently rolling benches and plateaus which lend themselves to activities such as horseback riding, wildlife observation, photography, and hunting.
This site has a variety of spring and summer flowers which are particularly noticeable after good moisture periods. It has good aethetic appeal when not severely disturbed.
Winters are cold, however, relatively mild spring, fall and summer months are attractive to recreationists.Supporting information
Other references
Updates and revisions for this ESD were conducted as part of a 2007-2012 Interagency Technical Assistance Agreement between the Bureau of Indian Affairs–Navajo Region and the NRCS-Arizona.
Contributors
Karlynn Huling
Ken Gishi
Kenneth Gishi
Larry D. EllicottRangeland 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) Kenneth Gishi Contact for lead author State Rangeland Management Specialist, NRCS-Arizona State Office Date 07/30/2012 Approved by Approval date Composition (Indicators 10 and 12) based on Annual Production Indicators
-
Number and extent of rills:
None expected, a few, short (less than 3 feet) can form on steeper slopes. There may a slight increase of rills following intense storm events. -
Presence of water flow patterns:
Very rare due to high amount of rock and bare ground cover. -
Number and height of erosional pedestals or terracettes:
Rare. However, in areas of sufficient plant cover small pedastals of 1 inch are expected around long-lived shrubs. -
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
Bare ground can range from 5 – 25 percent. Do not count intact biological crust as bare ground. -
Number of gullies and erosion associated with gullies:
None expected. -
Extent of wind scoured, blowouts and/or depositional areas:
Uncommon, but some active deposition around long-lived shrubs is normal. -
Amount of litter movement (describe size and distance expected to travel):
Litter movement is fairly common, especially fines litter (<1/8” in diameter). Fine litter can move up to 3 feet across the site. Litter will accumulate around plant bases, soil depressions or rock obstructions. -
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
The site is expected to have an average stability rating of 2-3. -
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Surface horizon depth will range from 2-4 inches with a single grain; loose structure. Surface textures will range from sand to loamy sand with color depending on parent material. Use specific soil survey information for supplemental information to this indicator. -
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Site is dominated by a shrub canopy with a lower canopy of perennial grasses and forbs, followed by annuals. Shrubs and perennial grasses provide site protection by capturing and slowing runoff to promote infiltration. -
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
None, soils are normally very shallow to bedrock. -
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:
Low Shrubs > Perennial Grasses > Large ShrubsSub-dominant:
Perennial Forbs > Annuals > Biological Soil CrustOther:
Small TreesAdditional:
-
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
All plant functional groups are adapted to survival in all but the most severe droughts. Severe winter droughts affect the shrubs the most. Severe summer droughts affect grasses the most. -
Average percent litter cover (%) and depth ( in):
-
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
75 – 125 lbs/ac expected in a normal year. -
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:
Plants native to site, but that can and do increase on the site include broom snakeweed, Fendler’s threeawn and Greene rabbitbrush. Non-natives that can invade the site with or without disturbance include cheatgrass, red brome and prickly Russian thistle. -
Perennial plant reproductive capability:
All plants native to the site are adapted to the climate and are capable of producing seeds, stolons, and/or rhizomes except during the most severe droughts.
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PrintThe Ecosystem Dynamics Interpretive Tool is an information system framework developed by the USDA-ARS Jornada Experimental Range, USDA Natural Resources Conservation Service, and New Mexico State University.
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