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Ecological site R009XY003OR

Fan 10-15 PZ

Last updated: 9/05/2019
Accessed: 11/21/2024

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General information

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.

Associated sites

R009XY050OR	Loamy Bench 10-15 PZ Loamy bench 10-15 PZ
R009XY051OR	Loamy South 10-15 PZ Loamy South 10-15 PZ
R009XY052OR	Loamy Shallow South 10-15 PZ Loamy Shallow South 10-15 PZ
R009XY053OR	Very Shallow South 10-15 PZ Very Shallow South 10-15 PZ
R009XY054OR	Loamy North 10-15 PZ Loamy North 10-15 PZ

Similar sites

R009XY050OR	Loamy Bench 10-15 PZ Loamy Bench 10-15 PZ

R009XY050OR

Loamy Bench 10-15 PZ

Loamy Bench 10-15 PZ

Table 1. Dominant plant species

Tree	Not specified
Shrub	Not specified
Herbaceous	Not specified

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Physiographic features

This site occurs in canyons along lower slopes and on fans a the outlet of perennial and ephemeral streams. Braiding at stream otulets and fan coalescence is often common. Slopes range from 2 to 30% with slopes of 2 to 15% being most typical. Elevation varies from 800 to 2400 feet.

Table 2. Representative physiographic features

Landforms	(1) Fan
Elevation	800 – 2,400 ft
Slope	2 – 30%
Water table depth	60 in
Aspect	Aspect is not a significant factor

Climatic features

The annual precipitation ranges from 10 to 15 inches. Limited deep seasonal subsurface flows augment the precipition. The precipitation occurs as rain and snow during the months of November through March. Localized, occasionally severe, convection storms occur during the summer. The mean annual air temperature is approximately 50 degrees F. Extreme temperatures range from 100 degrees F. to -20 degrees F. Soil temperature regimes are mesic. The frost free period ranges from 90 to 140 days. The period of optimum plant growth is from April through mid July.

Table 3. Representative climatic features

Frost-free period (average)	140 days
Freeze-free period (average)	0 days
Precipitation total (average)	15 in

Soil features

The soils of this site are formed in deep aluvium, colluvium and loess. They are deep to very deep. Typically the surface layer is a silt loam or gravelly silt loam over a loamy to cobbly clay loam subsoil. Stoniness is variable. Soil permeabilty is moderate. Teh available water holding capacity (AWC) is 6 to 10 inches. Localized, deep, seasonal subsurface flows augment the available water. The erosion potential is moderate.

Table 4. Representative soil features

Surface texture	(1) Silt loam (2) Very gravelly silt loam
Family particle size	(1) Loamy
Drainage class	Well drained
Permeability class	Moderate

Ecological dynamics

Range in Characteristics:
Variability in plant compostion and yeild is dependent on soil depth and the extent of lateral subsurface water flow. Netleaf Hackberry increases with availability of localized subsurface flows. Bluebunch wheatgrass increases in drier areas. As a site susceptable to fire, the amount of netleaf hackberry is influenced by fire frequency. It typically resprouts and persists under light fuel burns. Higher mortality occurs in dense stands with heavy fuel loads. Hackberry is a slow-growing species averaging 13 feet in 50 years. Recruitment rates are typically low.

Response to Disturbance:
If the condition of the site deteriorates as a result of over grazign, bluebunch wheatgrass decreases along with other palatable understory grasses and forbs. Sand dropseed increases along with lesser amounts of red threeawn. Cheatgrass, Japanese brome and annual annual fescues invade along with marestail and a variety of other unpalatable forbs. Hackberry reproduction becomes limited. Minor amounts of rhizomatous shrubs, sumac and poison ivy, continue to increase slowly. With further deterioration areas of bare ground increses, forage production decreases and soil erosion accelerates.

State and transition model

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Standard diagram

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Click on state and transition labels to scroll to the respective text

Ecosystem states

1. Historic Climax Plant Community

State 1 submodel, plant communities

1.1. Historic Climax Plant Community

State 1
Historic Climax Plant Community

Community 1.1
Historic Climax Plant Community

The potential nativ plant community is dominated by a complex of shrubs and bluebunch wheatgrass in a pattern arrangement. The dominant shrub is netleaf hackberry. Serviceberry is present along with minor amounts of smooth sumac and poison ivy. Bluebunch wheatgrass is the dominant grass along with lesser amounts of sand dropseed and a variety of forbs. the potential vegetative composistion is approximately 75 percent grass, 20 percent shrubs and 5 percent forbs.

Figure 2. 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	884	1060	1235
Shrub/Vine	195	312	429
Forb	65	137	208
Total	1144	1509	1872

Additional community tables

Table 6. Community 1.1 plant community composition

Group	Common name	Symbol	Scientific name	Annual production (lb/acre)	Foliar cover (%)
Grass/Grasslike
1	Perennial Deep-rooted Dominant			780–910
	bluebunch wheatgrass	PSSP6	Pseudoroegneria spicata	780–910	–
2	Perennial Deep-rooted Subdominant			65–130
	sand dropseed	SPCR	Sporobolus cryptandrus	65–130	–
5	Perrennial Others (PPGG) All			39–195
	purple threeawn	ARPU9	Aristida purpurea	8–39	–
	needle and thread	HECO26	Hesperostipa comata	8–39	–
	prairie Junegrass	KOMA	Koeleria macrantha	8–39	–
	basin wildrye	LECI4	Leymus cinereus	8–39	–
	Sandberg bluegrass	POSE	Poa secunda	0	–
Forb
7	Perennial all Dominant			26–65
	desertparsley	LOMAT	Lomatium	26–65	–
8	Perennial all Subdominant			26–78
	lupine	LUPIN	Lupinus	13–39	–
	plains pricklypear	OPPO	Opuntia polyacantha	13–39	–
9	PPFF			1–7
	common yarrow	ACMI2	Achillea millefolium	1–7	–
	agoseris	AGOSE	Agoseris	1–7	–
	shaggy fleabane	ERPU2	Erigeron pumilus	1–7	–
	aster	EUCEP2	Eucephalus	1–7	–
	hairy false goldenaster	HEVI4	Heterotheca villosa	1–7	–
	hawkweed	HIERA	Hieracium	1–7	–
	beardtongue	PENST	Penstemon	1–7	–
	phacelia	PHACE	Phacelia	1–7	–
	phlox	PHLOX	Phlox	1–7	–
	narrowleaf skullcap	SCAN3	Scutellaria angustifolia	1–7	–
Shrub/Vine
11	Perennial Evergreen Dominant			130–260
	curl-leaf mountain mahogany	CELE3	Cercocarpus ledifolius	130–260	–
12	Perennial Evergreen Subdominant			26–65
	Saskatoon serviceberry	AMAL2	Amelanchier alnifolia	26–65	–
15	SSSS			39–104
	leather flower	CLEMA	Clematis	10–26	–
	buckthorn	RHAMN	Rhamnus	10–26	–
	smooth sumac	RHGL	Rhus glabra	10–26	–
	western poison ivy	TORY	Toxicodendron rydbergii	10–26	–

Interpretations

Animal community

Livestock Grazing:
This site is siuted to spring, fall and winter use by cattle, sheep and horses under a planned grazing system. The key species is bluebunch wheatgrass. Bluebunch wheatgrass can be damaged if heavily grazed during periods of flowring and seed formation when root reserves and soil moisture is low. Use in the spring should be postponed until the soils are firm enough to prevent trampling damage, soil compaction and streambank sloughing. As a sediment deposition area, adequate plant cover shold be left in the fall to catch sediment and protect streambanks and secondary overflow channels during spring runoff events.
Wildlife:
When the ecological condition is high this site provides food and cover for deer, elk, other mammals and upland birds. IT is an importatn wintering area for deer and elk.

Hydrological functions

The soils of this site have excellent water holding capacities providing late season water for plant growth. As a site which often occurs at stream outlets in depostion areas the site is inherently unstable. In natural undisturbed conditions it supports a braided stream pattern, one with numerous secondary overflow channels. This pattern functions in reducing stream energy and allowing sediment depostion. The depostion potential of the site should be considered in hydrology analysis and developing plannning alternatives. The hydrologic cover condition is excellent when the ecological condition is high.

Other information

When in poor condition the site has potential for mechanical range seeding. When incised channels are present, rehabilitation will markedly improve production, redcue downstream sedimentation and improve hydrologic characteristics.

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)	Jeff Repp
Contact for lead author	Oregon NRCS State Rangeland Management Specialist
Date	07/27/2012
Approved by	Bob Gillaspy
Approval date
Composition (Indicators 10 and 12) based on	Annual Production

Indicators

Number and extent of rills:
None to some, moderate sheet & rill erosion hazard
Presence of water flow patterns:
Occasional to rare flooding with seasonal high water table
Number and height of erosional pedestals or terracettes:
None
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
5-10%
Number of gullies and erosion associated with gullies:
Poor resistance to erosion when cover is lacking - subject to incision and downcutting
Extent of wind scoured, blowouts and/or depositional areas:
None, slight wind erosion hazard
Amount of litter movement (describe size and distance expected to travel):
Fine - limited movement
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
Moderately resistant to erosion with adequate cover: aggregate stability = 3-4
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Deep silt loam or gravelly silt loam with variable stoniness: Low OM (1-3%)
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Significant ground cover (90-100%) and moderate slopes (3-30%) effectively limit rainfall impact and overland flow
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
None
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:
Bluebunch wheatgrass > Hackberry > Sand dropseed > other perennial grasses > other shrubs > Saskatoon serviceberry = Lomatium > other forbs > lupine = Plains pricklypear

Sub-dominant:

Other:

Additional:
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
Normal decadence and mortality expected
Average percent litter cover (%) and depth ( in):
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
Favorable: 1600, Normal: 1300, Unfavorable: 1000 lbs/acre/year at high RSI (HCPC)
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:
Perennial brush species will increase with deterioration of plant community. Cheatgrass and Medusahead invade sites that have lost deep rooted perennial grass functional groups
Perennial plant reproductive capability:
All soecies should be capable of reproducing annually

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