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Draft. A draft ecological site description is either incomplete or has not undergone quality control and quality assurance review.
Table 1. Dominant plant species
Tree Not specified
Shrub Not specified
Herbaceous Not specified
Physiographic features
1. Elevation: Low: 5000 ft High: 6500 ft
2. Aspect: all
3. Percent Slope: Low 0% High 6%
The landscape consists primarily of steep canyon terrain with gently sloping valley floors frequently dominated by shrubs. Intermittent and perenial streams frequently are deeply incised in the valley floor.Table 2. Representative physiographic features
Landforms (1) Canyon
(2) Valley floor
Elevation 5000 – 6500 ft Slope 0 – 6 % Aspect Aspect is not a significant factor Climatic features
a. Hard freeze free period: 175 to 205 days (24 degrees F)
b. Freeze-free period: 150-180 days (28 degrees F)
c. Frost-free period: 125 to 155 days (32 degrees F)
d. Mean annual precipitation: 8 to 13 in
e. Mean annual air temperature: 46 to 56 degrees F
f. Mean annual soil temperature: 49 to 58 degrees FTable 3 Representative climatic features
Frost-free period (average) 170 days Freeze-free period (average) 140 days Precipitation total (average) 10 in BarLineFigure 1. Monthly precipitation range
BarLineFigure 2. Monthly average minimum and maximum temperature
Figure 3. Annual precipitation pattern
Figure 4 Annual average temperature pattern
">Influencing water features
None
Soil features
Characteristic soils in this site are very deep and well drained located on terraces, mesa tops, benches and foothill fans. They formed in alluvium materials derived mainly from shale and sandstone or fine textured eolian materials. Soils are moderately alkaline with deeper horizons occasionally alkaline. Surface texture is sandy fine loam, loam, or clay loam. Subsurface texture is silty clay loam to 60 inches. Permeability is slow, erodibility is high.
List of Soil Taxonomic Units or Soil Mapping Units for all soils included in this site:
Mack fine sandy loam 0-6% slope
Mikim clay loam 1-3% slope
Mikim loam 3-6% slope
Recapture fine sandy loam 0-6% slope
Redland fine sandy loam 0-6% slopeEcological dynamics
When this range site is near its potential, alkali sacaton, western wheatgrass, galleta, bottlebrush squirreltail and needleandthread make up over 40% of the plant community. Western wheatgrass is dominant in areas that receive additional moisture such as drainage bottoms. Ohter grasses that occur in the community are Indian ricegrass, sand dropseed, red threeawn, native bluegrasses, blue grama and inland saltgrass.
Forbs such as scarlet globemallow, wooly Indianwheat, mountain pepperweed, lomatium, daisy fleabane and pursh seepweed make up only 10-15% of the potential plant community.
Shrubs and half shrubs such as black greasewood, spiny hopsage, shadscale, greenmolly summercypress, and basin big sagebrush make up 30 to 45 percent of the potential plant community. As the plant community declines in condition, grasses and forbs will decrease while shrubs and half shrubs such as black greasewood will increase to dominate the site. Annual invaders such as Russian thistle and downy brome will also increase as the range condition declines.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 textState 1
HCPCWhen this range site is near its potential, alkali sacaton, western wheatgrass, galleta, bottlebrush squirreltail and needleandthread make up over 40% of the plant community. Western wheatgrass is dominant in areas that receive additional moisture such as drainage bottoms. Ohter grasses that occur in the community are Indian ricegrass, sand dropseed, red threeawn, native bluegrasses, blue grama and inland saltgrass.
Forbs such as scarlet globemallow, wooly Indianwheat, mountain pepperweed, lomatium, daisy fleabane and pursh seepweed make up only 10-15% of the potential plant community.
Shrubs and half shrubs such as black greasewood, spiny hopsage, shadscale, greenmolly summercypress, and basin big sagebrush make up 30 to 45 percent of the potential plant community. As the plant community declines in condition, grasses and forbs will decrease while shrubs and half shrubs such as black greasewood will increase to dominate the site. Annual invaders such as Russian thistle and downy brome will also increase as the range condition declines.Community 1.1
HCPCOvergrazing with cattle will result in alkali sacaton, western wheatgrass, needleandthread, muttongrass, scarlet globemallow, shadscale, greenmolly summercypress, winterfat, bigelow sagebrush, bud sagebrush, and fourwing saltbush disappearing from the plant community. Red threeawn, sand dropseed, bottlebrush squirreltail, black greasewood, broom snakeweed and basin big sagebrush will increase. Russian thistle and downy brome will invade and become part of the vegetation. This will result in decreased forage production with a corresponding increase in runoff causing this site to have severe erosion problems.
Overgrazing with sheep will cause alkali sacaton, western wheatgrass, needleandthread, seepweed, shadscale, scarlet globemallow, greenmolly summercypress, basin big sagebrush, winterfat, bud sagebrush and bigelow sagebrush to decrease. This results in the same problems associated with overgrazing with cattle. Continued severe overgrazing with sheep and or cattle will result in black greasewood, broom snakeweed, Russian thistle, downy borme and red threeawn dominating this site.
Total Annual production:
Annual Production is distributed as follows:
Grasses and Grasslikes 40-60% of the total
Forbs 5-15% of the total
Shrubs and Half Shrubs 30-45% of the total
In excellent condition, the approximate total annual production (air-dry) is as follows:
Favorable: 800-1000 lbs/ac
Average: 650-800 lbs/ac
Unfavorable: 450-550 lbs/ac
Of this production 25 to 30% will likely be unpalatable to grazing animals or out of reach of grazing animals.Figure 5. Annual production by plant type (representative values) or group (midpoint values)
Table 4. Ground cover
Tree foliar cover 0% Shrub/vine/liana foliar cover 30-40% Grass/grasslike foliar cover 50-60% Forb foliar cover 10-20% 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% Additional community tables
Table 5. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Grass/Grasslike1 Grass 250–450 alkali sacaton SPAI Sporobolus airoides 50–113 – squirreltail ELEL5 Elymus elymoides 13–68 – needle and thread HECO26 Hesperostipa comata 13–45 – leafy heliotrope HECO4 Heliotropium confertifolium 13–45 – sand dropseed SPCR Sporobolus cryptandrus 13–45 – western wheatgrass PASM Pascopyrum smithii 0–23 – Indian ricegrass ACHY Achnatherum hymenoides 0–23 – sixweeks fescue VUOC Vulpia octoflora 0–14 – saltgrass DISP Distichlis spicata 0–14 – muttongrass POFE Poa fendleriana 0–9 – purple threeawn ARPU9 Aristida purpurea 0–9 – blue grama BOGR2 Bouteloua gracilis 0–9 – Forb2 Forbs 30–54 scarlet globemallow SPCO Sphaeralcea coccinea 1–3 – prairie fleabane ERST3 Erigeron strigosus 0–1 – rosy gilia GISI Gilia sinuata 0–1 – mountain pepperweed LEMO2 Lepidium montanum 0–1 – nineleaf biscuitroot LOTR2 Lomatium triternatum 0–1 – woolly plantain PLPA2 Plantago patagonica 0–1 – Shrub/Vine3 Shrubs 190–342 greasewood SAVE4 Sarcobatus vermiculatus 19–51 – shadscale saltbush ATCO Atriplex confertifolia 10–34 – spiny hopsage GRSP Grayia spinosa 6–17 – broom snakeweed GUSA2 Gutierrezia sarothrae 6–17 – big sagebrush ARTR2 Artemisia tridentata 0–17 – fourwing saltbush ATCA2 Atriplex canescens 0–17 – Bigelow sage ARBI3 Artemisia bigelovii 0–14 – Interpretations
Animal community
Guide to Initial Stocking Rates:
Stocking rates given below are based on continuous use for the entire growing season and are intended only as an initial guide. Forage needs are calculated on the basis of 900 lbs of air-dry forage per animal unit month (AUM). To maintain proper use and allow for forage that disappears through trampling, small herbivore use, weathering, etc., 35 percent of the palatable forage produced is considered available for grazing by large herbivores.
Condition Class/ Percent Climax Vegetation/ Aum/Ac/ Ac/AUM/ Ac/AU
Excellent/ 76-100/ .25-.33/ 3-4/ 36-48
Good/ 51-75/ .14-.24/ 4-7/ 48-84
Fair/ 26-50/ .07-.13/ 7-14/ 84-168
Poor/ 0-25- .03-.06/ 15-30/ 180-360
Adjustments to the initial stocking rates should be made as needed to obtain proper use. With specialized grazing systems, large livestock breeds, uncontrolled big game, inacessability, dormant season use, presence of introduced forage species, seeded rangeland etc., stocking rate adjustments will be required.
Wildlife species list:
pronghorn, muledeer, coyote, blacktailed jackrabbit, desert cottontail, upland game birds, small mammals, song birds, reptiles
Grazing:
When this site is producing near its potential, it provides good grazing for cattle and sheep as well as providing good habitat for many wildlife species. The animal forage preferences change as the season progresses. Alkali sacaton, western wheatgrass, and Indian ricegrass are very palatable during the spring and summer grazing period. Bud sagebrush, winterfat, shadscale and fourwing saltbush are used primarily during the fall and winter period as the grasses and forbs become dormant and lose their nutritive value. This site responds very well to deferment during the spring and summer seasons. Planned Grazing Systems are an excellent management tool to maintain or improve the vegetation on this site.
Vegetative palatibility will influence proper grazing use considerations. The season of use, weather, kind of grazing animal, past grazing history and the plant compostion will directly influence animal preference and performance.
Major Poisonous Plants to Livestock:
Plant Common Name/ Livestock Affected/ Type of Poisoning/ Season Serious
broom snakeweed/ sheep, cattle/ may cause abortion/ spring and early summer, other forage scarce
black greasewood/ sheep, cattle/ depression, weakness, death/ early spring, diet consists exclusively of greasewood
Wildlife Values:
This site has good potential for wildlife habitat because of the mixture of grasses, forbs and shrubs that it produces. The site provides habitat at least for part of the year for cottontail rabbit, blacktailed jackrabbit, pronghorn, deer, reptiles, raptors and rodents. As this site nears in potential plant community, the diversity of wildlife species will also increase.Hydrological functions
Soils in this site are grouped into the "B" hydrologic groups, as outlined in the Soils of Colorado Loss Factors and Erodibility Hydrologic Groupings 1979 Handbook. Field investigations are needed to determine hydrologic cover conditions and hydrologic curve numbers. Refer to SCS National Engineering Handbook, Section 4, and Peak Flows in Colorado Handbook for more information.
Recreational uses
This site has good aesthetic appeal and natural beauty because of its setting. This site is found primarily in valleys with steep mountainous canyon terrain adjacent to the site.
Wood products
No known potential production
Other information
Typical Locations:
Bridge Canyon, Montezuma County, Colorado
Endangered Plants and Animals:
Currently no known endangered plants or animals are dependent on this site.
Counties in which this Range Site is Located:
La Plata
MontezumaSupporting information
Contributors
CS/TO
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
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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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