Natural Resources
Conservation Service
Ecological site R035XB030NM
Sandy Loam Upland
6-10"
Last updated: 5/20/2025
Accessed: 05/02/2026
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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 very deep, well-drained soils. Surface textures include loamy fine sand and fine sandy loam. Landforms include elevated stream terraces, fan remnants, and cuestas. Slopes range from 1 to 8 percent.
Table 1. Dominant plant species
Tree Not specified
Shrub (1) Atriplex canescens
(2) Krascheninnikovia lanataHerbaceous (1) Achnatherum hymenoides
Physiographic features
This site occurs on treads of high stream terraces, fan remnants of undulating plateaus, and cuestas. It does not benefit from run-in moisture from adjacent areas, nor does it suffer from excessive loss from runoff. It occurs on all exposures. Slopes range from 1 to 8 percent. Elevations range from 4,700 to 6,100 feet.
Table 2. Representative physiographic features
Landforms (1) Fan remnant
(2) Cuesta
(3) Dip slope
Flooding frequency None Ponding frequency None Elevation 4700 – 6100 ft Slope 1 – 8 % Water table depth 60 in Aspect Aspect is not a significant factor Climatic features
Mean annual precipitation varies from 7 to 10 inches. About 60% of this moisture comes as rain from April through October. May and June are the driest months. Most of the moisture from November through March comes as snow. Winds of high velocity during late winter and early spring are common.
Mean temperature for the hottest month, July, is about 83 degrees F. Mean temperature for the coldest month, January, is about 27 degrees F. Extreme temperatures of 104 degrees F and –17 degrees F have been recorded. The frost-free period ranges from 140 to 160 days.
The cool-season plants start growth in March and end with plant maturity and seed dissemination about mid-June. During June, July, August, and September, the warm-season plants make optimum growth taking advantage of the warm temperature and moisture from tropical air out of the Gulf of Mexico. About 40% of the total precipitation is received during these summer months. The other 60% received during the fall-winter-spring months influences cool-season plants.Table 3 Representative climatic features
Frost-free period (average) 160 days Freeze-free period (average) 170 days Precipitation total (average) 10 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 are very deep and well drained. They are formed in alluvium and eolium derived from sandstone. Surface textures include loamy fine sand and fine sandy loam. The subsoil has textures of very fine sandy loam, fine sandy loam, loamy coarse sand, and loamy sand. Permeability is moderately rapid. Available water holding capacity is low to moderate. Runoff is very low to low, and the hazard of water erosion is very slight to slight. The hazard of soil blowing is severe. The soils are slightly to strongly alkaline (pH 7.4-9.0), nonsaline to slightly saline below 24 inches (EC 0-8), and nonsodic to slightly sodic (SAR 0-13).
Characteristic taxonomic units are:
Shiprock SSA:
120-Nageezi-Denazar (Nageezi part)
173-Shiprock fine sandy loam
205-Shiprock-Farb Complex (Shiprock part)
240-Nageezi loamy fine sand
Other soils included are:Table 4. Representative soil features
Surface texture (1) Loamy fine sand
(2) Fine sandy loam
Family particle size (1) Loamy
Drainage class Well drained Permeability class Moderately rapid Soil depth 60 – 67 in Surface fragment cover <=3" 0 – 8 % Surface fragment cover >3" Not specified Available water capacity
(0-40in)4 – 6 in Calcium carbonate equivalent
(0-40in)1 – 30 % Electrical conductivity
(0-40in)0 – 8 mmhos/cm Sodium adsorption ratio
(0-40in)0 – 13 Soil reaction (1:1 water)
(0-40in)7.4 – 9 Subsurface fragment volume <=3"
(Depth not specified)0 – 5 % Subsurface fragment volume >3"
(Depth not specified)Not specified Ecological dynamics
This site has a plant community made up primarily of short- and mid-grasses, some shrubs, and a small percentage of forbs. In the original plant community there is a mixture of both cool- and warm-season grasses. Plant species most likely to invade or increase on this site when it deteriorates are cheatgrass and other annual weeds, sixweeks fescue, galleta, and broom snakeweed. Continuous livestock grazing during winter and spring will decrease the cool-season grasses, which are replaced by lower forage value grasses and shrubs
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 2 submodel, plant communities
State 1
Reference StateCommunity 1.1
Reference Plant CommunityThis site has a plant community made up primarily of short- and mid-grasses, some shrubs, and a small percentage of forbs. In the original plant community there is a mixture of both cool- and warm-season grasses. Plant species most likely to invade or increase on this site when it deteriorates are cheatgrass and other annual weeds, sixweeks fescue, galleta, and broom snakeweed. Continuous livestock grazing during winter and spring will decrease the cool-season grasses, which are replaced by lower forage value grasses and shrubs.
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 240 320 440 Shrub/Vine 45 60 82 Forb 10 20 30 Total 295 400 552 Figure 5. Plant community growth curve (percent production by month). NM0380 , R035XB030NM-Sandy Loam Upland 6 to 10 inch-Reference State. R035XB030NM-Sandy Loam Upland 6 to 10 inch-Reference State.
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec J F M A M J J A S O N D 6 6 7 6 6 5 11 14 12 12 8 7 Community 1.2
Shrubland/GrasslandThis phase is a relatively balanced mix of shrubs and native grasses.
Pathway P1.1a
Community 1.1 to 1.2Season-long grazing providing little rest and recovery for preferred grazed plants during critical growing periods, coupled with high utilization.
Key drivers
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Wildlife grazing or browsing
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Livestock grazing or browsing
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Climate
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Fire frequency
Key ecosystem services affected
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Nutrient cycling
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Food and fiber: livestock forage
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Climate regulation: carbon cycling and storage
Pathway P1.2a
Community 1.2 to 1.1Prescribed grazing.
Conservation practices
Prescribed Grazing Key drivers
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Wildlife grazing or browsing
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Livestock grazing or browsing
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Climate
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Fire frequency
Key ecosystem services affected
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Nutrient cycling
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Food and fiber: livestock forage
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Climate regulation: carbon cycling and storage
State 2
Current Potential - Introduction of Non-Native AnnualsThis phase is characterized by an established community of invasive annuals.
Community 2.1
Mixed Native GrasslandThis phase contains a mix of native grasses.
Community 2.2
Shrubland/GrasslandThis phase is a relatively balanced mix of shrubs and grasses.
Community 2.3
Warm Season GrassesThis phase is dominated by warm season grasses.
Pathway P2.1b
Community 2.1 to 2.2Season-long grazing providing little rest and recovery for preferred grazed plants during critical growing periods, coupled with high utilization.
Key drivers
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Wildlife grazing or browsing
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Livestock grazing or browsing
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Climate
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Fire frequency
Key ecosystem services affected
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Nutrient cycling
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Food and fiber: livestock forage
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Climate regulation: carbon cycling and storage
Pathway P2.1a
Community 2.1 to 2.3Continuous cool-season grazing providing little rest and recovery for preferred grazed plants during critical growing periods, coupled with high utilization.
Key drivers
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Wildlife grazing or browsing
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Livestock grazing or browsing
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Climate
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Fire frequency
Key ecosystem services affected
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Nutrient cycling
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Food and fiber: livestock forage
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Climate regulation: carbon cycling and storage
Pathway P2.2a
Community 2.2 to 2.1Prescribed grazing
Conservation practices
Prescribed Grazing Key drivers
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Wildlife grazing or browsing
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Livestock grazing or browsing
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Climate
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Fire frequency
Key ecosystem services affected
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Nutrient cycling
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Food and fiber: livestock forage
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Climate regulation: carbon cycling and storage
Pathway P2.3a
Community 2.3 to 2.1Prescribed grazing
Conservation practices
Prescribed Grazing Key drivers
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Wildlife grazing or browsing
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Livestock grazing or browsing
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Climate
Key ecosystem services affected
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Nutrient cycling
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Food and fiber: livestock forage
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Climate regulation: carbon cycling and storage
Pathway P2.3b
Community 2.3 to 2.2Shrub encroachment
Conservation practices
Prescribed Grazing Key drivers
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Wildlife grazing or browsing
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Livestock grazing or browsing
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Climate
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Fire frequency
Key ecosystem services affected
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Nutrient cycling
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Food and fiber: livestock forage
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Climate regulation: carbon cycling and storage
State 3
Degraded StateThis state exhibits evidence of degradation such as excessive bare ground.
State 4
Annuals StateThis state is dominated by invasive annuals.
Transition T1A
State 1 to 2Season-long grazing providing little rest and recovery for preferred grazed plants during critical growing periods, coupled with high utilization.
Key drivers
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Seed dispersal by livestock
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Climate
Key ecosystem services affected
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Erosion control
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Nutrient cycling
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Climate regulation: carbon cycling and storage
Transition T2A
State 2 to 3Season-long grazing providing little rest and recovery for preferred grazed plants during critical growing periods, coupled with high utilization.
Key drivers
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Livestock grazing or browsing
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Mechanical soil disturbance
Key ecosystem services affected
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Nutrient cycling
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Food and fiber: livestock forage
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Climate regulation: carbon cycling and storage
Transition T2B
State 2 to 4Season-long grazing providing little rest and recovery for preferred grazed plants during critical growing periods, coupled with high utilization. Establishment of invasive annuals.
Key drivers
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Fire
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Livestock grazing or browsing
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Climate
Key ecosystem services affected
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Nutrient cycling
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Food and fiber: livestock forage
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Climate regulation: carbon cycling and storage
Restoration pathway R3A
State 3 to 2Prescribed grazing, seeding
Conservation practices
Range Planting Prescribed Grazing Transition T3A
State 3 to 4Establishment of invasive annuals.
Key drivers
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Fire
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Livestock grazing or browsing
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Climate
Key ecosystem services affected
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Nutrient cycling
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Food and fiber: livestock forage
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Climate regulation: carbon cycling and storage
Restoration pathway R4A
State 4 to 3Prescribed grazing, seeding
Conservation practices
Range Planting Prescribed Grazing Herbicide resistant weed management Additional community tables
Table 6. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Grass/Grasslike1 Indian ricegrass 100–140 Indian ricegrass ACHY Achnatherum hymenoides 100–140 – 2 galleta 40–60 James' galleta PLJA Pleuraphis jamesii 40–60 – 3 blue grama 20–40 blue grama BOGR2 Bouteloua gracilis 20–40 – 4 sand dropseed 0–10 sand dropseed SPCR Sporobolus cryptandrus 0–8 – 5 Fendler's threeawn 0–10 Fendler's threeawn ARPUF Aristida purpurea var. fendleriana 0–8 – 6 Fendler (red) threeawn 0–5 Fendler threeawn ARPUL Aristida purpurea var. longiseta 0–4 – 7 squirreltail 10–20 squirreltail ELEL5 Elymus elymoides 8–20 – 8 mesa dropseed 0–10 mesa dropseed SPFL2 Sporobolus flexuosus 0–12 – 9 sandhill muhly 0–5 sandhill muhly MUPU2 Muhlenbergia pungens 0–4 – 10 other perennial grasses 0–10 Grass, perennial 2GP Grass, perennial 0–12 – Forb11 rose heath (smallflower aster) 0–10 rose heath CHER2 Chaetopappa ericoides 0–8 – 12 globemallow 0–5 globemallow SPHAE Sphaeralcea 0–4 – 13 other perennial forbs 0–10 Forb, perennial 2FP Forb, perennial 0–12 – 14 annual forbs 0–10 Shrub/Vine15 fourwing saltbush 5–20 fourwing saltbush ATCA2 Atriplex canescens 4–20 – 16 winterfat 0–20 17 plains pricklypear 0–5 plains pricklypear OPPO Opuntia polyacantha 0–4 – 18 Greene's rabbitbrush 0–5 Greene's rabbitbrush CHGR6 Chrysothamnus greenei 0–4 – 19 broom snakeweed 5–20 broom snakeweed GUSA2 Gutierrezia sarothrae 4–20 – 20 other shrubs 0–10 Shrub (>.5m) 2SHRUB Shrub (>.5m) 0–8 – Table 7. Community 1.2 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 8. Community 2.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 9. Community 2.2 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 10. Community 2.3 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Interpretations
Animal community
This site is well used by wildlife that dig or burrow and those which require open grassland.
Hydrological functions
This site normally receives about 7-10 inches of annual precipitation. Most summer rainfall occurs as brief, sometimes heavy, thunderstorms. Slopes range from 1-8 percent. Permeability is moderately rapid. Runoff is very low to low, and the hazard of water erosion is very slight to slight.
Recreational uses
Open grasslands of the undulating plateaus and cuestas of this site are aesthetically appealing and provide recreational activities such as hunting, horseback riding, and wildlife observation.
Wood products
This site has no significant value for wood products.
Other products
Grazing: This site is suitable for yearlong grazing by all classes of livestock. Grazing systems adapt well to this site and should be used. This site is susceptible to erosion, particularly overgrazed areas, old roads, cattle trails, and high-use areas.
Supporting information
Inventory data references
The potential historic climax plant community has been determined by study of range relict areas or areas protected from excessive grazing. Trends in plant communities going from heavily grazed areas to lightly grazed areas, seasonal use pastures, and historical accounts have also been used.
Type locality
Location 1: San Juan County, NM Township/Range/Section T25N R17W S15 General legal description Little Water Topographic Quadrangle – 5 miles ESE of Little Water, NM Section 15, Township 25N, Range 17W – Navajo Reservation, NM. Contributors
David Trujillo
John Tunberg
Michael Carpinelli
UnknownApproval
Kendra Moseley, 5/20/2025
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 05/02/2026 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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