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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.
MLRA notes
Major Land Resource Area (MLRA): 025X–Owyhee High Plateau
The Owyhee High Plateau, MLRA 25, lies within the Intermontane Plateaus physiographic province. The southern half is found in the Great Basin while the northern half is located in the Columbia Plateaus. The southern section of the Owyhee High Plateau is characterized by isolated, uplifted fault-block mountain ranges separated by narrow, aggraded desert plains. This geologically older terrain has been dissected by numerous streams draining to the Humboldt River. The northern section forms the southern boundary of the extensive Columbia Plateau basalt flows. Deep, narrow canyons drain to the Snake River across the broad volcanic plain.
This MLRA is characteristically cooler and wetter than the neighboring MLRAs of the Great Basin. Elevation ranges from 3,000 to 7,550 feet on rolling plateaus and in gently sloping basins. It is more than 9,840 feet on some steep mountains. The average annual precipitation in most of this area is typically 11 to 22 inches. It increases to as much as 49 inches at the higher elevations. Precipitation occurs mainly as snow in winter. The supply of water from precipitation and streamflow is small and unreliable, except along major rivers. Streamflow depends largely on accumulated snow in the mountains.
The dominant soil orders in this MLRA are Aridisols and Mollisols. The soils in the area dominantly have a mesic or frigid temperature regime and an aridic, arid bordering on xeric, or xeric moisture regime. Most of the soils formed in mixed parent material. Volcanic ash and loess mantle the landscape. Surface soil textures are loam and silt loam, and have ashy texture modifiers in some cases. Argillic horizons occur on the more stable landforms.Ecological site concept
This site is on alluvial terraces and flood plains of ephemeral streams in high elevation plateaus and mountain valleys. Soils associated with this site formed in alluvium from volcanic rock. These soils are deep and very deep and somewhat poorly to poorly drained. Slopes are less than 5 percent and elevations range from 5,000-6,500 feet (1524-1981 meters). Important abiotic factors contributing to the presence of this ecological site include a seasonal water table within 9.8 inches (25 cm) of the soil surface and frequent flooding in spring and early summer. The reference plant community is dominated by a dense stand of Nevada bluegrass, sedges, and rushes.
Associated sites
R025XY003NV LOAMY BOTTOM 8-14 P.Z.
R025XY005NV WET MEADOW
R025XY046ID MEADOW
R025XY014OR LOAMY 13-16 PZ
Similar sites
R025XY039ID DRY MEADOW
R025XY006NV DRY MEADOW
Table 1. Dominant plant species
Tree Not specified
Shrub Not specified
Herbaceous (1) Poa nevadensis
(2) CarexPhysiographic features
This site is on alluvial terraces and flood plains of ephemeral streams in high elevation plateaus and mountain valleys. It is at the upper end of drainages occupying broad to narrow swale areas. Slopes range from 1 to 5 percent. Elevation varies from 5,000 to 7,000 feet (1,524 to 2,133 meters).
Table 2. Representative physiographic features
Landforms (1) Flood plain
Runoff class High to very high Flooding duration Brief (2 to 7 days) to long (7 to 30 days) Flooding frequency None to frequent Ponding frequency None Elevation 5000 – 7000 ft Slope 1 – 5 % Water table depth 6 – 12 in Aspect W, NW, N, NE, E, SE, S, SW Climatic features
The annual precipitation ranges from 13 to 16 inches (33 to 41cm), most of which occurs in the form of snow during the months of November through March. Ephemeral subsurface moisture flow augments the precipitation. Localized convection storms occasionally occur during the summer. The soil temperature regime is frigid with a mean annual air temperature of 44 degrees F. Temperature extremes range from 90 to -30 degrees F. The frost free period ranges from 30 to 90 days. The optimum growth period for native plants is from April through July.
Table 3 Representative climatic features
Frost-free period (characteristic range) 30-90 days Freeze-free period (characteristic range) 40-120 days Precipitation total (characteristic range) 10-20 in Frost-free period (average) 30 days Freeze-free period (average) 80 days Precipitation total (average) 20 in Characteristic rangeActual rangeBarLineFigure 1. Monthly precipitation range
Characteristic rangeActual rangeBarLineFigure 2. Monthly minimum temperature range
Characteristic rangeActual rangeBarLineFigure 3. Monthly maximum temperature range
BarLineFigure 4. Monthly average minimum and maximum temperature
Figure 5. Annual precipitation pattern
Figure 6 Annual average temperature pattern
Climate stations used
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(1) MCDERMITT [USC00264935], Jordan Valley, NV
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(2) MC DERMITT 26 N [USC00355335], Jordan Valley, OR
">Influencing water features
Dry Meadow is influenced by adjacent streams and frequent flooding in the spring and early summer. The soil profile is characterized by a seasonal water table within 9.8 inches (25 cm) of the soil surface resulting from endo-saturation.
Soil features
The soils of this site are recent, deep to very deep and poorly drained. Typically the surface layer is a silt loam to silty clay loam. The subsoil is a silty clay loam to clay. The substratum varies from alluvium to bedrock. Permeability is slow to moderately slow. The available water holding capacity is about 4 to 7 inches (10 to 18cm) for the profile. Seasonal subsurface flows from adjacent slopes augment the available water.
Soil series correlated to this site include: WelchTable 4. Representative soil features
Parent material (1) Alluvium
Surface texture (1) Silt loam
(2) Silty clay loam
Family particle size (1) Fine-loamy
Drainage class Poorly drained Permeability class Slow to moderately slow Soil depth 40 – 60 in Surface fragment cover <=3" 2 – 6 % Surface fragment cover >3" 0 – 2 % Available water capacity
(0-40in)4 – 7 in Soil reaction (1:1 water)
(0-40in)6 – 8 Subsurface fragment volume <=3"
(0-40in)0 – 10 % Subsurface fragment volume >3"
(0-40in)0 – 2 % Ecological dynamics
This ecological site occurs on the floodplain of a low gradient stream. Riparian areas differ from adjacent uplands in vegetative composition and structure, geomorphology, hydrology, microclimate, and fuel characteristics. Composition is complex and is tied closely to hydrologic processes, geomorphology, and use history. This site is highly productive and the vegetation is tolerant of saturation in the soil profile. Vegetation serves as an indicator of soil moisture gradient. Species classified as obligate or facultative wet occur closest to the stream channel. Moving perpendicular to the stream channel vegetation become more tolerant of dry soil conditions.
This site is characterized by a dominance of perennial bunchgrasses or grasslikes. Nevada bluegrass (Poa secunda) is dominant. Sedges and rushes are common. The amount of Nevada bluegrass in relation to sedge depends on the extent and duration of lateral subsurface water flows. Sedges increase on areas of meadows receiving subsurface flows late into the growing season. Conversely, Nevada bluegrass increases on areas of meadows with limited drainage areas.
This ecological site occupies a small percentage of the landscape, but provides critical habitat for a variety of wildlife. Ecological diversity of this system is maintained by natural disturbance regimes, including flooding and drought periods. Fire regimes in riparian areas are related to the fire regime of the adjacent upland community, although its suggested that fire frequency and severity was generally lower and than adjacent communities (Dwire and Kauffman 2003).
The presence of invasive species has the ability to significantly alter disturbance regimes from their natural range of variation. Precipitation patterns are highly variable and unpredictable throughout this area. Dryland riparian areas are tolerant of prolonged drought conditions, however decline in overall vegetative cover and production is expected during drought periods. Inappropriate management and upstream disturbance can lead to bank destabilization (Fleischner 1994) and soil erosion. Where stream channels become deeper and wider, causing water to flow faster (DJ Krueper, 1996), the water table is lowered, flooding is reduced, and a more drought tolerant plant community can invade. With time, the site can transition to sod forming bluegrasses such as Kentucky bluegrass.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 submodel, plant communities
State 1
Reference StateThis represents the historical reference state in pristine conditions with no exotic species present. Variability in depth to water table and seasonal fluctuations support native facultative wetland vegetation and vegetated communities include all historical functional and structural groups. The historical disturbance regime is intact and driven primarily by climate which influences drought and flood cycles. The resilience and resistance of the site is bolstered by negative feedbacks between vegetation establishment and hydrologic processes that maintains a dynamic equilibrium with geomorphological processes.
Characteristics and indicators. Depth to water table and species composition with any complex of meadow sites can be highly variable. Conditions may vary within the site at a given location due to a minor changes in soils, flooding frequency and duration, seasonal water table fluctuations, and competition between plants that are mostly rhizomatous.
Community 1.1
Reference Plant CommunityThe reference plant community is dominated by Nevada bluegrass. Sedges, rushes, and a variety of other grasses are common. Proportion of the individual species shifts with drought and flooding cycles and proximity to a stream channel. An assortment of perennial forbs are present but do not account for a large part of the plant community by weight. Silver sagebrush and rose are present but are typically less than 5 percent by weight.
Figure 7. 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 1675 1860 2045 Forb 75 85 90 Shrub/Vine 50 55 65 Total 1800 2000 2200 State 2
Current Potential StateThis state is similar to the reference state yet includes a component of non-native species such as Kentucky bluegrass (Poa pratensis), common timothy (Phleum pretense), and meadow foxtail (Alopecurus pratensis). Ecological process and function have not been altered fundamentally by this low level of invasion, yet resistance and resilience are decreased. Erosion processes are still within a historical range of variation, yet with continued vegetation loss the site risks a transition to an alternative state. Variability in depth to water table and seasonal fluctuations support native vegetation. Vegetated communities include all historical functional and structural groups, yet composition and richness may be reduced. This state is common due to widespread invasion of non-native meadow grasses in the Western US. Prolonged improperly managed grazing will promote the spread of Kentucky bluegrass and increase cover of shrubs (State 3). Further improperly managed grazing will increase bareground, increase erosion and risk a transition to a drained state (State 4).
State 3
Invaded StateSoil compaction, trampling and sustained overutilization has altered vegetated composition and increased bare ground. Relative to the current potential state, composition of wetland facultative species has been reduced and silver sage has increased. Much of the Nevada bluegrass, sedge, and rush cover has been replaced by Kentucky bluegrass. The state may also be invaded by exotic annual grasses and forbs and exotic tap rooted perennials. Soil erosion and vegetation pedestalling is often present. Banks are moderately stable, hydrology may be altered with somewhat lowered water tables.
State 4
Incised StateSustained disturbance may lead to unstable stream banks, entrenched channels and headcuts. Active floodplains and primary terraces will become disconnected from the channel and evolve into high terraces with significantly lowered water tables. This will often lead to the replacement of facultative wetland communities with mountain big sagebrush communities. Plant community composition within this state will vary and may depend on adjacent vegetation types, water table levels, past disturbance history, drought and current management.
Transition T1.1
State 1 to 2Invasion of non-native meadow grasses
Transition T2.1
State 2 to 3Sustained improperly managed grazing during times of year when soils are most susceptible to compaction, and when graminoids are most prone to damage by trampling and over utilization.
Transition T2.2
State 2 to 4This transition may be the result of several disturbances that lower water tables beyond depths that support facultative wetland vegetation, alter sediment supply and transport leading to scouring and channel incision, or directly increase flow velocities or flashiness.
Transition T3.1
State 3 to 4This transition may be the result of several disturbances that lower water tables beyond depths that support facultative wetland vegetation, alter sediment supply and transport leading to scouring and channel incision, or directly increase flow velocities or flashiness.
Additional community tables
Table 6. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Grass/Grasslike1 Dominant, perennial, deep rooted 1000–1400 bluegrass POA Poa 1000–1400 – 2 Sub-dominant, perennial 460–960 sedge CAREX Carex 300–500 – rush JUNCU Juncus 100–300 – bluegrass POA Poa 60–160 – 3 All other perennial grasses 80–260 bluegrass POA Poa 60–160 – squirreltail ELEL5 Elymus elymoides 10–40 – Idaho fescue FEID Festuca idahoensis 10–40 – prairie Junegrass KOMA Koeleria macrantha 10–40 – bluebunch wheatgrass PSSPS Pseudoroegneria spicata ssp. spicata 10–40 – Forb4 Dominant perennial forbs 40–80 common yarrow ACMI2 Achillea millefolium 20–40 – cinquefoil POTEN Potentilla 20–40 – 5 All other perennial forbs 0–60 sticky purple geranium GEVI2 Geranium viscosissimum 0–20 – lupine LUPIN Lupinus 0–20 – buttercup RANUN Ranunculus 0–20 – Shrub/Vine6 Dominant shrubs 40–80 silver sagebrush ARCA13 Artemisia cana 20–40 – rose ROSA5 Rosa 20–40 – 7 Dominant, perennial, deciduous shrubs 20–40 Interpretations
Animal community
This site offers food and cover for mule deer, antelope, rodents and a variety of birds. It is an important summer and fall use area for mule deer and antelope.
This dry meadow ecological site provides diverse habitat for wetland and upland wildlife species. The characteristic seasonal hydrology results in abundant forage attracting invertebrate and vertebrate animals to this site. Habitat is provided for resident and migratory animals including western toad, western rattlesnake, shrews, bats, jackrabbits, ground squirrels, mice, coyote, red fox, badger, sage-grouse, Ferruginous hawk, prairie falcon, grasshopper sparrow, horned lark, and western meadowlark. Large herbivore use of the ecological site is dominated by mule deer, pronghorn antelope, and elk. Native reptiles and amphibians are reliant on these dry meadow sites during the year. Loss of site hydrology significantly reduces the habitat value of this site and also adjacent ecological sites. Open water is seasonal, only being provided by seasonal runoff, ponding, flooding, seasonal high water table, and natural springs.
Grazing Interpretations.
This site is suitable for livestock grazing in late spring after soils have dried sufficiently to prevent trampling and in the summer and fall.Other information
The soils in this site have excellent water holding capacities providing late season water for plant growth and slow water release to streams. When incised channels are present, rehabilitation will markedly improve production and restore good hydrologic characteristics. On altered sites, the reintroduction of desirable plants may be needed to fully restore the site potential.
Supporting information
Inventory data references
Vale District BLM Ecological Site Inventory NASIS component and pedon data Range Site Descriptions Field knowledge of range-trained personnel
Type locality
Location 1: Malheur County, OR Township/Range/Section TT27S RR45E S12 General legal description Located in SW 1/4 of Sec 12 on upper South Fork of Carter Creek, north side of Spring Mountain (SI 40 with small areas of SI 70) References
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Dwire, K. and J. Kauffman. 2003. Fire and riparian ecosystems in landscapes in the western United States. Forest Ecology and Management. 178:61–74.
Other references
Fleischner, T.L., 1994. Ecological Costs of Livestock Grazing in Western North America. Conservation Biology Vol 8 No. 3 pp 629-644.
Krueper, D.J. 1996. Effects of livestock management on Southwestern riparian ecosystems. In: Shaw, Douglas W.; Finch, Deborah M., tech coords. Desired future conditions for Southwestern riparian ecosystems: Bringing interests and concerns together. 1995 Sept. 18-22, 1995; Albuquerque, NM. General Technical Report RM-GTR-272. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station. p. 281-301.Contributors
Bahn, A. And R.H. Barrett
Bob Gillaspy
E. Ersch
Jennifer MoffittApproval
Kendra Moseley, 4/24/2024
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 08/06/2026 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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