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Draft. A draft ecological site description is either incomplete or has not undergone quality control and quality assurance review.
Classification relationships
Riparian vegetation class (CWHR)
Associated sites
R019XD043CA Loamy Hill 16-20" p.z.
Loamy Hill 16-20" p.z.
R019XD046CA Loamy Upland 16-20" p.z.
Loamy Upland 16-20" p.z.
R019XD047CA Coastal Terrace 14-16" p.z.
Coastal Terrace 14-16" p.z.
Table 1. Dominant plant species
Tree (1) Platanus racemosa
(2) Quercus agrifoliaShrub (1) Salix lasiolepis
(2) Baccharis salicifoliaHerbaceous Not specified
Physiographic features
This site occurs on alluvial fans, flood plains and fluvial terraces. Slope range from 0 to 15 percent. Aspects are variable, and elevation ranges from 10 to 1400 feet.
There are three soil components correlated with this site. The wettest is the Fluvaquents, which are frequently flooded for very long durations throughout the year. The Cumulic Haploxerolls are frequently flooded from November to April for brief periods. The driest component is the Elder soil series, which is rarely flooded from November through April for a very brief duration.Table 2. Representative physiographic features
Landforms (1) Alluvial fan
(2) Flood plain
(3) Inset fan
Flooding duration Very brief (4 to 48 hours) to very long (more than 30 days) Flooding frequency Rare to frequent Ponding frequency None Elevation 10 – 1400 ft Slope 0 – 15 % Aspect Aspect is not a significant factor Climatic features
This site receives slightly more annual rainfall than the more coastal sites due to movement of hot and cold air masses and pressure systems influenced by the ocean and surrounding mountains. Roughly 94% of yearly precipitation falls form November through April. The driest months are June, July and August, with those months historically receiving trace amounts of rainfall. The average annual precipitation ranges from 14 to 24 inches. The mean annual air temperature ranges from 60 to 64 degrees F.
There are no reliable climate stations for this specific ecological site. The two stations listed (Oxnard and Los Angeles Civic Center) are on the extreme northwest and southwest of the area.
Table 3 Representative climatic features
Frost-free period (average) 350 days Freeze-free period (average) 0 days Precipitation total (average) 20 in BarLineFigure 1. Monthly precipitation range
BarLineFigure 2. Monthly average minimum and maximum temperature
">Influencing water features
This site is seasonally flooded from November to April, for very long to very brief periods, by small streams and drainages. There are areas within these map units that qualify for jurisdictional wetlands. Site specific field verification would be needed to determine wetland status or extent of riparian vegetation.
Soil features
This ecological site is associated with the Elder soil series which are Coarse-loamy, mixed, superactive, thermic Cumulic Haploxerolls. At a higher level this site is associated with other Cumulic Haploxerolls and Fluvaquents. These soils are all very deep or deep, well drained soils that formed in alluvial material derived from mixed rock sources. The Elder soil has a fine sandy loam surface texture in the upper 8 inches, with sandy loam, and fine sandy loam subsurface textures to greater than 72 inches. The Cumulic Haploxerolls are stratified, with a sandy loam surface texture and a clay loam subsurface texture to 69 inches. Below 69 inches is extremely gravelly coarse sand. The Fluvaquents have a loam surface texture in the upper 5 inches, with a sandy loam texture from 5 to 14 inches, a loamy sand from 14 to 19, extremely gravelly sand from 19 to 48 inches, and gravelly coarse sand below 48 inches. These soils have some calcium carbonates with a CCE of 1 to 5%. The Elder soil can have 1 to 2 percent salinity. Organic matter in the upper layers of these soils ranges from 0 to 4 percent. These soils are often used for farming, and have been or are still being plowed and irrigated.
This site is correlated with the following map units and components within the Santa Monica Mountains Soil Survey Area (CA692):
Map Unit Component Percent
175 Cumulic Haploxerolls 3
176 Cumulic Haploxerolls 1
177 Cumulic Haploxerolls 1
178 Cumulic Haploxerolls 1
190 Cumulic Haploxerolls 1
191 Cumulic Haploxerolls 2
200 Cumulic Haploxerolls, clayey 6
200 Cumulic Haploxerolls 85
201 Cumulic Haploxerolls, clayey 6
201 Cumulic Haploxerolls 85
202 Elder, coastal 5
202 Fluvaquents 70
210 Cumulic Haploxerolls, clayey 6
210 Cumulic Haploxerolls 85
211 Cumulic Haploxerolls, clayey 6
211 Cumulic Haploxerolls 85
220 Elder, coastal 85
240 Cumulic Haploxerolls 1
251 Cumulic Haploxerolls 1
252 Elder, coastal 5
280 Cumulic Haploxerolls 1
310 Elder, coastal 1
311 Elder, coastal 5
330 Elder, coastal 1
340 Elder, coastal 5Table 4. Representative soil features
Surface texture (1) Loam
Family particle size (1) Loamy
Drainage class Poorly drained to well drained Permeability class Moderately rapid Soil depth 60 – 0 in Surface fragment cover <=3" 0 – 15 % Surface fragment cover >3" 0 – 5 % Available water capacity
(0-40in)4.1 – 10.6 in Calcium carbonate equivalent
(0-40in)0 – 5 % Soil reaction (1:1 water)
(0-40in)6.6 – 8.4 Subsurface fragment volume <=3"
(Depth not specified)0 – 15 % Subsurface fragment volume >3"
(Depth not specified)2 – 35 % Ecological dynamics
This is a riparian ecological site with a climax community dominated by California sycamore (Platanus racemosa), Southern California walnut (Juglans californica), and California live oak (Quercus agrifolia). Other plants that are present are arroyo willow (Salix lasiolepis), and mule's fat (Baccharis salicifolia), giant wildrye (Leymus condensatus), laurel sumac (Malosma laurina), and California wildrose (Rosa californica). Cottonwoods (Populus spp.) are also common in this plant community, but they were not noted in NRCS transects.
There is insufficient data for developing a state and transition model for this ecological site. Some of the successional patterns can be described from research done on similar riparian plant communities. More information is needed to distinguish successional stages from hydrological boundaries.
This ecological site is found in confined valley bottoms and broad alluvial flats, adjacent to stream channels. The climax community is a winter deciduous woodland, with canopy heights that reach up to 100’. Canopy cover ranges from 40 to 80 percent, with an open understory. Seasonal flooding can wash out the mature canopy, or create bare areas from fresh sediment deposition. Mule’s fat and willows are generally the primary invaders into the fresh sediment. If cottonwoods are present they will grow quickly, and shade out the willow community in 25 to 30 years. California sycamore and Coast live oak grow slower, but will eventually dominate the canopy. It is important to maintain the natural disturbances in order to have a variety of plant communities present. The willow community is important nesting habitat for the least Bell's vireo (Vireo bellii pusillus) and southwestern willow flycatcher (Empidonax traillii extimus), which are listed Federally endangered and Federally threatened species respectively, by the U.S. Fish and Wildlife Service. There are several other birds that also prefer to build there nest in the lower branches of the willow thickets.
A major threat to the plant communities associated with this ecological site is giant reed (Arundo donax) a non-native perennial rhizomatous grass. This grass tends to invade into recently disturbed areas, and forms monotypic stands. Giant reed grass has the potential to become the climax plant community, in place of native species. Giant reed grass does not provide the habitat required for the endangered or threatened birds mentioned above. Also, it uses up much more water than the native species, which may change the surface and groundwater hydrology. Giant reed has extensive and thickly matted roots that tend to stabilize stream banks, reducing the ability for the stream to meander across the floodplain. Giant reed can alter the fire regime in these riparian communities because it is highly flammable and continuous. Naturally the riparian forest do not burn easily, and they are not well adapted to fire. Fire tends to have a high mortality rate in the riparian forests.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
Riparian terraceCommunity 1.1
Riparian terraceThe dominant species for this site vary depending upon successional status and hydrologic fluctuations. Plants encountered in the NRCS transects are: arroyo willow (Salix lasiolepis), California sagebrush (Artemisia californica), mule's fat (Baccharis salicifolia), Southern California walnut (Juglans californica), giant wildrye (Leymus condensatus), laurel sumac (Malosma laurina), California sycamore (Platanus racemosa), California live oak (Quercus agrifolia), and California wildrose (Rosa californica). There are other annual and perennial forbs, annual grasses, perennial grasses, perennial grasslike plants, and other shrubs that combined compose 46 percent of the annual production or about 1800 Lbs/acre.
Figure 3. Annual production by plant type (representative values) or group (midpoint values)
Additional community tables
Table 5. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Shrub/Vine1 Shrubs 730–3200 arroyo willow SALA6 Salix lasiolepis 440–1340 – coastal sagebrush ARCA11 Artemisia californica 110–335 – mule-fat BASA4 Baccharis salicifolia 110–335 – laurel sumac MALA6 Malosma laurina 110–335 – California wildrose ROCA2 Rosa californica 45–135 – Tree2 Tree 265–905 Southern California walnut JUCA Juglans californica 110–335 – California sycamore PLRA Platanus racemosa 110–335 – California live oak QUAG Quercus agrifolia 45–135 – Forb3 other annual and perennial forbs 400–1200 Grass/Grasslike4 Perennial grasses 245–740 giant wildrye LECO12 Leymus condensatus 110–335 – 5 Annual grasses 220–670 6 Perennial grasslike 45–135 Interpretations
Supporting information
Other references
Bell, G. 1997. Ecology and management of Arundo donax, and approaches to riparian habitat restoration in Southern California. In Brock, J. H., Wade, M., Pysek, P., and Green, D. (Eds.): Plant Invasions: Studies from North America and Europe. Blackhuys Publishers, Leiden, The Netherlands, pp. 103-113.
Steinberg, Peter D.; Howard, Janet L. (2002, December). Quercus agrifolia. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory(Producer). Available: http://www.fs.fed.us/database/feis/[].
Contributors
Curtis Talbot, Marchel Munnecke
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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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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