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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.
Table 1. Dominant plant species
Tree Not specified
Shrub Not specified
Herbaceous Not specified
Physiographic features
This site occurs on gently sloping to moderately steep low hills and mesa side slopes. Oftentimes it is associated with shale badlands and sandstone rock outcrops. Exposures are variable. Slopes range from 15 to 45 percent. Elevations range from 5,600 to 6,800 feet above sea level.
Table 2. Representative physiographic features
Landforms (1) Hill
Flooding duration Brief (2 to 7 days) Flooding frequency Occasional Elevation 5600 – 6800 ft Slope 15 – 45 % Water table depth 42 – 72 in Aspect Aspect is not a significant factor Climatic features
This site has an arid, mild, dry climate with distinct seasonal temperature variations and large annual and diurnal temperature changes.
Mean annual precipitation varies from about 7 to 10 inches. Deviations of 4 inches or more are quite common. Distribution is 65% during the native-plant growth period, which is from April through September. May and June are the dry months. During July, August, and September, 3.5 inches of precipitation influences the presence and production of warm-season plants. Late-fall and winter moisture is conducive to the production of cool-season plants, which usually begin growth in March and end with plant maturity and seed dissemination. This usually takes place in the early part of June when the moisture deficiency and warmer temperatures occur. The Gulf of Mexico is the principal source of moisture for summer precipitation, which is characterized by brief afternoon thunderstorms. Winter moisture occurs as light rain or snow.
Temperatures vary from a monthly mean of 75 degrees F in July to 27 degrees F in January, and from an annual maximum of 106 degrees F to an annual minimum of -35 degrees F. The average last killing frost in the spring is May 8, and the average first killing frost in the fall is October 10. The frost-free season is approximately 160 days. Temperatures are conducive to native grass and forb growth from April through September. Maximum shrub growth occurs in the spring months.
The wind blows most frequently from an easterly direction; however, a majority of the stronger winds (10 to 25 miles per hour) are from a westerly quadrant. Spring is the windiest season. Average hourly wind velocities are near 6 miles per hour. Spring and summer winds increase transpiration rates of native plants and rapidly dry the surface soil. Small soil particles are often displaced by the wind near the soil surface and often results in structural damage to native plants, especially young seedlings.
Climate data were obtained from http://www.wrcc.sage.dri.edu/summary/climsmnm.html web site using 50% probability for freeze-free and frost-free seasons using 28.5 degrees F and 32.5 degrees F, respectively.Table 3 Representative climatic features
Frost-free period (average) 150 days Freeze-free period (average) 180 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 not influenced by water from a wetland or stream.<br />
Soil features
The soils are moderately deep to deep and moderately well drained. Surface textures range from very fine sandy loams, loams, and clay loams. Subsoils are generally fine-textured.
The soils on this site are delicate and very susceptible to erosion by wind and water. Dissection of the site by gullies is common.
Water intake is slow, permeability is slow, but water-holding capacity is moderate to high.
Table 4. Representative soil features
Surface texture (1) Very fine sandy loam
(2) Loam
(3) Clay loam
Family particle size (1) Clayey
Drainage class Somewhat poorly drained to moderately well drained Permeability class Slow to moderately slow Soil depth 60 – 72 in Available water capacity
(0-40in)3 – 6 in Electrical conductivity
(0-40in)0 – 8 mmhos/cm Soil reaction (1:1 water)
(0-40in)7.9 – 9 Subsurface fragment volume <=3"
(Depth not specified)15 – 35 % Subsurface fragment volume >3"
(Depth not specified)15 – 35 % Ecological dynamics
The vegetation on this site presents a scrub juniper/pinyon savannah aspect understoried by a variety of shrubs, half-shrubs, grasses, and forbs. North slopes support more trees than south slopes, which are fairly open.
Other species include: sandhill muhly, sixweeks fescue, mat muhly, brome grasses, Russian thistle, kochia, fleabane, cholla cactus, yucca spp., and black greasewood.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 textEcosystem states
State 1 submodel, plant communities
State 1
Historic Climax Plant CommunityCommunity 1.1
Historic Climax Plant CommunityThe vegetation on this site presents a scrub juniper/pinyon savannah aspect understoried by a variety of shrubs, half-shrubs, grasses, and forbs. North slopes support more trees than south slopes, which are fairly open.
Other species include: sandhill muhly, sixweeks fescue, mat muhly, brome grasses, Russian thistle, kochia, fleabane, cholla cactus, yucca spp., and black greasewood.
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 210 345 480 Forb 21 35 48 Total 231 380 528 Table 6. Ground cover
Tree foliar cover 0% Shrub/vine/liana foliar cover 0% Grass/grasslike foliar cover 0% Forb foliar cover 0% Non-vascular plants 0% Biological crusts 0% Litter 10% Surface fragments >0.25" and <=3" 0% Surface fragments >3" 0% Bedrock 0% Water 0% Bare ground 60% Figure 5. Plant community growth curve (percent production by month). NM0909 , R035XB009NM-Shale Hills-HCPC. Juniper/pinyon savannah with an understory of shrubs, grasses and forbs. .
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 7 10 10 25 30 10 3 0 0 Additional community tables
Table 7. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Grass/Grasslike1 86–115 Indian ricegrass ACHY Achnatherum hymenoides 86–115 – needle and thread HECO26 Hesperostipa comata 86–115 – New Mexico feathergrass HENE5 Hesperostipa neomexicana 86–115 – 2 86–115 blue grama BOGR2 Bouteloua gracilis 86–115 – James' galleta PLJA Pleuraphis jamesii 86–115 – 3 58–86 alkali sacaton SPAI Sporobolus airoides 58–86 – 4 17–46 prairie Junegrass KOMA Koeleria macrantha 17–46 – muttongrass POFE Poa fendleriana 17–46 – 5 17–40 squirreltail ELEL5 Elymus elymoides 17–40 – western wheatgrass PASM Pascopyrum smithii 17–40 – 6 17–40 Graminoid (grass or grass-like) 2GRAM Graminoid (grass or grass-like) 17–40 – wheatgrass PASCO Pascopyrum 17–40 – dropseed SPORO Sporobolus 17–40 – Forb7 6–17 buckwheat ERIOG Eriogonum 6–17 – 8 6–17 Forb (herbaceous, not grass nor grass-like) 2FORB Forb (herbaceous, not grass nor grass-like) 6–17 – scarlet Indian paintbrush CACO17 Castilleja coccinea 6–17 – locoweed OXYTR Oxytropis 6–17 – Tree9 29–86 juniper JUNIP Juniperus 29–86 – twoneedle pinyon PIED Pinus edulis 29–86 – Shrub/Vine10 29–58 hairy mountain mahogany CEMOP Cercocarpus montanus var. paucidentatus 29–58 – Mexican cliffrose PUME Purshia mexicana 29–58 – antelope bitterbrush PUTR2 Purshia tridentata 29–58 – 11 17–40 big sagebrush ARTR2 Artemisia tridentata 17–40 – rabbitbrush CHRYS9 Chrysothamnus 17–40 – 12 17–40 fourwing saltbush ATCA2 Atriplex canescens 17–40 – winterfat KRLA2 Krascheninnikovia lanata 17–40 – 13 0–17 Shrub, deciduous 2SD Shrub, deciduous 0–17 – Interpretations
Animal community
Habitat for Wildlife: No Data
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
Green River-------------------B
Walrees-----------------------C
Recreational uses
This site is suited to hunting, hiking, horseback riding, photography, and nature observation. It is stark but scenic due to its association with colorful soils and rock outcrops.
Wood products
Wood products include fuelwood and fence posts. Care in harvesting these products should be taken due to the delicacy of the soils.
Other products
Grazing:
Approximately 70 percent of the vegetative production on this site is suitable for grazing or browsing by domestic livestock and wildlife. Grazing distribution can be a problem if adequate watering, salt locations, and fencing is not provided.
A decrease in cool-season grasses (Indian ricegrass, needle-and-thread and muttongrass) and fourwing saltbush, and an increase in blue grama, galleta, big sagebrush, rabbitbrush, and juniper indicate deterioration of the potential plant community. Severe deterioration is indicated by a large void of herbaceous species.
Due to the delicacy of the site, a planned grazing system, which would provide periodic grazings and rests, should be implemented. This would provide more cover for the soil as well as more nutritious and higher-producing forage for the grazing animals.
Other information
Guide to Suggested Initial Stocking Rate Acres per Animal Unit Month
Similarity Index--------Ac/AUM
100 - 76---------------4.5 – 6.1
75 – 51----------------6.0 – 9.1
50 – 26----------------9.0 – 18.2
25 – 0-----------------18.2+Supporting information
Type locality
Location 1: San Juan County, NM Other references
Data collection for this site was done in conjunction with the progressive soil surveys within the San Juan River Valley, Mesas and Plateaus, Major Land Resource Area 35 of New Mexico. This site has been mapped and correlated with soils in the following soil surveys: San Juan, McKinley.
Characteristic soils are:
Green RiverContributors
Don Sylvester
Elizabeth Wright
John Tunberg
Michael CarpinelliRangeland 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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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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