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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.
Ecological site concept
This site occurs on soils that are moderately deep to very deep, are at least slightly effervescent at the surface (dilute HCl reaction), and contain carbonate-rich layers within 20 inches of the surface. Slopes range from 5 to 15 percent.
Table 1. Dominant plant species
Tree (1) Juniperus
(2) Pinus edulisShrub (1) Krascheninnikovia lanata
(2) Atriplex canescensHerbaceous (1) Pascopyrum smithii
(2) Bouteloua gracilisLegacy ID
R035XG129NM
Physiographic features
This site occurs on moderately sloping valley side slopes. It can also occur as sloping benches or rolling hills above valley bottoms and floodplain positions. Slopes range from 5 to 15 percent. Elevations range from 6,000 to 7,300 feet.
Table 2. Representative physiographic features
Landforms (1) Fan piedmont
(2) Plain
Flooding frequency None to rare Ponding frequency None Elevation 5500 – 7300 ft Slope 0 – 10 % Aspect Aspect is not a significant factor Climatic features
Average annual precipitation varies from about 10 inches to just over 16 inches. Fluctuations ranging from about 5 inches to 25 inches are not uncommon. The overall climate is characterized by cold dry winters in which winter moisture is less than summer. As much as half or more of the annual precipitation can be expected to come during the period of July through September. Thus, fall conditions are often more favorable for good growth of cool-season perennial grasses, shrubs, and forbs than are those of spring.
The average frost-free season is about 120 days and extends from approximately mid-May to early or mid-September. Average annual air temperatures are 50 degrees F or lower and summer maximums rarely exceed 100 degree F. Winter minimums typically approach or go below zero. Monthly mean temperatures exceed 70 degrees F for the period of July and August.
Rainfall patterns generally favor warm-season perennial vegetation, while the temperature regime tends to favor cool-season vegetation. This creates a somewhat complex community of plants on a given range site which is quite susceptible to disturbance and is at or near its productive potential only when both the natural warm- and cool- season dominants are present.
Table 3 Representative climatic features
Frost-free period (average) 170 days Freeze-free period (average) 250 days Precipitation total (average) 20 in BarLineFigure 2. Monthly precipitation range
BarLineFigure 3. Monthly average minimum and maximum temperature
">Influencing water features
This is an upland site, and is not associated with water features or wetlands. During heavy rain events, this site may receive run-on moisture from landforms above and contribute runoff to landforms below.
Soil features
The soils of this site are well drained and moderately deep to deep. The surface textures range from loams to clay loams. Water-holding capacity is moderate to high and permeability is moderate. These soils are typically slightly effervescent on the surface with effervescence increasing with depth. There is a calcareous horizon within 20 inches of the surface that may be weakly cemented. This may affect the rooting depth of the vegetation. These soils are highly susceptible to wind and water erosion.
Characteristic taxonomic units are:
Harvey loam, Flaco cobbly loam, loamTable 4. Representative soil features
Surface texture (1) Clay loam
(2) Sandy clay loam
(3) Very fine sandy loam
Family particle size (1) Clayey
Drainage class Well drained Permeability class Slow to moderately rapid Soil depth 20 – 72 in Surface fragment cover <=3" 5 – 15 % Surface fragment cover >3" 0 – 3 % Available water capacity
(0-40in)2 – 5 in Calcium carbonate equivalent
(0-40in)15 – 30 % Electrical conductivity
(0-40in)0 – 4 mmhos/cm Sodium adsorption ratio
(0-40in)0 – 5 Soil reaction (1:1 water)
(0-40in)7.4 – 8.4 Subsurface fragment volume <=3"
(Depth not specified)5 – 20 % Subsurface fragment volume >3"
(Depth not specified)1 – 3 % Ecological dynamics
Overview:
This site occurs on piedmont slopes, plains, and mesa tops. The soils are moderately deep to deep with a horizon high in calcium carbonate within twenty inches of the surface. This site is often associated with Loamy and Malpais sites. Loamy sites often occur adjacent to, or as inclusions interspersed within Limy sites. On basalt- capped mesas, Malpais sites are occasionally associated with Limy sites. The historic plant community of the Limy site is a grassland characterized by a mixture of cool- and warm-season grasses with occasional shrubs and forbs. Western wheatgrass is the dominant grass, and winterfat is the key shrub species. Overgrazing can reduce grass cover and effect a change in grass species dominance. The loss of grass cover can reduce the competitive influence of grasses and may facilitate the transition to the Woody-Encroached state.
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 2 submodel, plant communities
State 1
Reference StateThis state represents the most ecologically stable conditions in terms of resistance to erosion. Moreover, this state has the highest potential for productivity and plant diversity.
Community 1.1
Reference Plant CommunityState Containing Historic Plant Community
Grassland: Western wheatgrass is the dominant grass of the historic plant community. Other important grasses that occur in significant amounts include sideoats grama, New Mexico feathergrass, needle and thread, blue grama, galleta, and black grama. At higher elevations (usually greater than 6,800 feet), black grama is typically only a minor component while western wheatgrass and blue grama may increase in percent composition. Winterfat is the key woody species for this site. Other species include fourwing saltbush, Bigelow sagebrush, rabbitbrush, spineless horsebrush, cholla and yucca. Piñon and juniper are typically minor components on this site, but may be found at greater densities at higher elevation within the Land Resource Unit. Overgrazing can cause a decrease in western wheatgrass and other cool-season grasses, sideoats grama, winterfat, and fourwing saltbush. Communities dominated by blue grama with western wheatgrass or galleta as the sub-dominant may result.
Diagnosis: Grass and litter cover are uniform with few large bare areas present. Evidence of erosion such as pedestalling of plants, rills, and gullies are infrequent.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)Grass/Grasslike 300 530 760 Shrub/Vine 40 75 100 Forb 30 50 70 Tree 0 10 20 Total 370 665 950 Table 6. Ground cover
Tree foliar cover 0% Shrub/vine/liana foliar cover 0% Grass/grasslike foliar cover 10-20% Forb foliar cover 0-10% Non-vascular plants 0% Biological crusts 0% Litter 10-20% Surface fragments >0.25" and <=3" 10-20% Surface fragments >3" 0-0% Bedrock 0% Water 0% Bare ground 50-60% Figure 5. Plant community growth curve (percent production by month). NM0319 , R035XG129NM-Limy-HCPC. WP-2 Limy HCPC.
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 10 10 10 20 25 15 5 0 0 State 2
Woody-EncroachedThis state is characterized by an abundance of woody plants.
Community 2.1
Woody-EncroachedAdditional States:
Woody-Encroached: This state is characterized by an increase in woody species, typically spineless horsebrush and or rabbitbrush, and in some instances at higher elevations, piñon and juniper. Blue grama is the dominant grass and galleta and threeawns are sub-dominants. Grass cover decreases as shrub/tree canopy increases.
Diagnosis: Grass production and species composition have decreased relative to the Grassland State. Grass and litter cover range from fairly uniform, to patchy with large bare areas present. Evidence of erosion including pedestalling of grasses, elongated water flow patterns, and rills may be common.
Transition to Woody-Encroached (1a) Loss of grass cover due to overgrazing and the associated reduced competition by grasses may facilitate woody encroachment.3
Key indicators of approach to transition:
* Decrease or change in composition or distribution of grass cover, such as dominance by blue grama.
* Increase in size and frequency of bare patches.
* Increase in amount of rabbitbrush, horsebrush, or juniper/piñon seedlings.
Transition back to Grassland (2b) Brush control is necessary to reduce the competitive influence of shrubs. Some positive results have been reported in controlling rabbitbrush with herbicides.2, 4 Root plowing and other mechanical control methods that sever the plant below the sprouting zone may reduce horsebrush and rabbitbrush densities. Horsebrush and rabbitbrush are fire-adapted species and can quickly increase or occupy a site following fire. Mechanical1, chemical, or a combination can be effective in reducing piñon/juniper densities. Prescribed grazing will help ensure adequate rest following brush control and will assist in the establishment and maintenance of grass cover.
Transition T1A
State 1 to 2Loss of grass cover due to overgrazing and the associated reduced competition by grasses may facilitate woody encroachment.3 Key indicators of approach to transition: * Decrease or change in composition or distribution of grass cover, such as dominance by blue grama. * Increase in size and frequency of bare patches. * Increase in amount of rabbitbrush, horsebrush, or juniper/piñon seedlings.
Restoration pathway R2A
State 2 to 1Brush control is necessary to reduce the competitive influence of shrubs. Some positive results have been reported in controlling rabbitbrush with herbicides. Root plowing and other mechanical control methods that sever the plant below the sprouting zone may reduce horsebrush and rabbitbrush densities. Horsebrush and rabbitbrush are fire-adapted species and can quickly increase or occupy a site following fire. Mechanical, chemical, or a combination can be effective in reducing piñon/juniper densities. Prescribed grazing will help ensure adequate rest following brush control and will assist in the establishment and maintenance of grass cover.
Additional community tables
Table 7. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Grass/Grasslike1 70–130 thickspike wheatgrass ELLAL Elymus lanceolatus ssp. lanceolatus 66–133 – western wheatgrass PASM Pascopyrum smithii 66–133 – 2 70–100 blue grama BOGR2 Bouteloua gracilis 66–99 – hairy grama BOHI2 Bouteloua hirsuta 66–99 – 3 70–130 needle and thread HECO26 Hesperostipa comata 66–133 – New Mexico feathergrass HENE5 Hesperostipa neomexicana 66–133 – 4 30–70 James' galleta PLJA Pleuraphis jamesii 33–66 – 5 20–30 alkali sacaton SPAI Sporobolus airoides 20–33 – 6 20–30 Indian ricegrass ACHY Achnatherum hymenoides 20–33 – 7 20–30 squirreltail ELEL5 Elymus elymoides 20–33 – 8 20–30 common wolfstail LYPH Lycurus phleoides 20–33 – spike dropseed SPCO4 Sporobolus contractus 20–33 – sand dropseed SPCR Sporobolus cryptandrus 20–33 – 9 70–99 sideoats grama BOCU Bouteloua curtipendula 66–99 – 10 30–70 black grama BOER4 Bouteloua eriopoda 33–66 – Shrub/Vine11 30–70 winterfat KRLA2 Krascheninnikovia lanata 33–66 – 12 10–30 fourwing saltbush ATCA2 Atriplex canescens 7–33 – 13 10–20 jointfir EPHED Ephedra 7–20 – 14 10–30 Bigelow sage ARBI3 Artemisia bigelovii 7–33 – 15 10–20 rubber rabbitbrush ERNAN5 Ericameria nauseosa ssp. nauseosa var. nauseosa 7–20 – broom snakeweed GUSA2 Gutierrezia sarothrae 7–20 – spineless horsebrush TECA2 Tetradymia canescens 7–20 – Tree16 10–20 juniper JUNIP Juniperus 7–20 – twoneedle pinyon PIED Pinus edulis 7–20 – Forb18 10–50 Forb, perennial 2FP Forb, perennial 7–53 – 19 10–30 Forb, annual 2FA Forb, annual 7–33 – Table 8. Community 2.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Interpretations
Animal community
This range site provides a habitat, which supports a resident animal community characterized by pronghorn antelope, blacktailed jackrabbit, badger, Gunnison's prairie dog, mourning dove, prairie rattlesnake, and American bison. The common raven, prairie falcon, and Mexican eagle hunt over this site. Mule deer feed on the site.
Hydrological functions
The runoff curve numbers are determined by field investigations using hydrologic cover conditions and hydrologic soil groups.
Hydrologic Interpretations
Soil Series--------------Hydrologic Group
Ildefonso-----------------------B
Falco---------------------------C
Recreational uses
This site offers fair to good potential for hiking, horseback riding, nature observation, and photography. Camping is limited due to the lack of water and shade. Hunting for antelope and small game is good. During years of abundant rainfall, the natural beauty is enhanced by an array of colorful wildflowers.
Wood products
Under the potential vegetative community, this site has little potential for wood products. However, in areas where pinyon and juniper have increased there is a limited potential for fencing material and fuelwood.
Other products
This site is suitable for grazing by all kinds and classes of livestock during all seasons of the year but is poorly suited to continuous year-long use. Species such as western wheatgrass, New Mexico feathergrass, sideoats grama, winterfat, and fourwing saltbush will decrease. They will be replaced by blue grama, broom snakeweed, yucca, and cholla. Continued deterioration of the site can cause severe erosion. This site responds best to a system of grazing that rotates the season of use. In some areas, pinyon and juniper have increased on this site and may appear as even-aged, long-lived stands.
Other information
Guide to Suggested Initial Stocking Rate Acres per Animal Unit Month
Similarity--------------------Index Ac/AUM
100 - 76-------------------------3.3-4.6
75 – 51-------------------------4.4-6.8
50 – 26-------------------------6.5-11.0
25 – 0---------------------------11.0+Supporting information
Other references
1. Brockway, D.G., R.G. Gatewood, and R.B. Paris. 2002. Restoring grassland savannas from degraded pinyon-juniper woodlands: effects of mechanical overstory reduction and slash treatment alternatives. Journal of Environmental Management. 64: 179-197.
2. Cluff, G.J., B.A. Roundy, R.A. Evans, and J.A. Young. 1983. Herbicidal control of greasewood (Sarcobatus vermiculatus) and salt rabbitbrush (Chrysothamnus nauseosus ssp. consimilis). Weed Science. 31: 275-279.
3. Johnsen, T.N., Jr. 1962. One-seeded juniper invasion of northern Arizona grasslands. Ecological Monographs. 32:187-207.
4. Whisenant, S.G. 1988. Control of threadleaf rubber rabbitbrush with herbicides. Journal of Range Management. 41: 470-472
Data collection for this site was done in conjunction with the progressive soil surveys within the New Mexico and Arizona Plateaus & Mesas Major Land Resource Area of New Mexico. This site has been mapped and correlated with soils in the following soil surveys: McKinley, Catron, Cibola, Socorro and Sandoval.
Contributors
Brenda Simpson
Christine Bishop
David Trujillo
Don Sylvester
John TunbergApproval
Kendra Moseley, 5/29/2025
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 04/16/2026 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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