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Draft. A draft ecological site description is either incomplete or has not undergone quality control and quality assurance review.
Associated sites
R019XD075CA Coastal Strand 14-18" P.Z.
The Coastal Strand 13-17" p.z. site usually separates the Salt Marsh 13-17" p.z. site from the ocean.
Similar sites
R019XD075CA Coastal Strand 14-18" P.Z.
Coastal Strand 13-17" p.z. is drier and located on beaches and dunes.
Table 1. Dominant plant species
Tree Not specified
Shrub Not specified
Herbaceous (1) Distichlis spicata
(2) SalicorniaPhysiographic features
This site occurs on tidal flats, floodplains, and fan skirts. This site is frequently flooded for long durations. The depth to the water table is about three feet. Slopes range from 0 to 2%. Elevations are from 0 to 10 feet.
Table 2. Representative physiographic features
Landforms (1) Tidal flat
(2) Flood plain
(3) Fan skirt
Flooding duration Very brief (4 to 48 hours) to brief (2 to 7 days) Flooding frequency Rare to frequent Ponding frequency None Elevation 0 – 10 ft Slope 0 – 2 % Water table depth 0 – 36 in Aspect Aspect is not a significant factor Climatic features
This site receives slightly less annual rainfall than the more inland 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 18 inches. The mean annual air temperature ranges from 60 to 64 degrees F.
Table 3 Representative climatic features
Frost-free period (average) 370 days Freeze-free period (average) 370 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 frequently flooded for brief durations, with depth to water table about 3 feet.
Soil features
This ecological site is associated with Camarillo and Pacheco soil series. These soils are both very deep, somewhat poorly drained soils that formed in alluvium derived from sedimentary rocks. They both have gleyed soil colors and other redoximorphic features due to prolonged periods of saturation. Gleyed features begin at 32 inches in the Pacheco Soils, and at 17 inches in the Camarillo soils. These soils strongly effervesce with dilute hydrochloric acid, indicating high levels of calcium carbonates. The surface PH for these soils is around 7.8, which becomes more alkaline with depth, up to a PH of 9. The sodium absorption ratio (SAR) ranges from 0 to 6 percent. The Pacheco soils are more affected by calcium carbonates and salinity than the Camarillo soils. Percent calcium carbonate ranges from 0 to 10 percent, and Salinity ranges from 2 to 8 percent for the Pacheco soils, while Percent calcium carbonate is 0 to 5, and Salinity is 0 to 8 for the Camarillo soils. The Camarillo soils have a sandy loam surface texture which extends to 24 inches. From 24 to 36 inches is a heavy loam; 36 to 44 inches is a fine sandy clay loam; 44 to 50 inches is a sandy loam; and fine sand continues from 50 to 80 inches. The Pacheco soils have a silt loam surface texture that extends down 20 inches. Below 20 inches is a clay loam subsurface texture.
The Camarillo soils are classified as fine-loamy, mixed, superactive, calcareous, thermic Aquic Xerofluvents, and the Pacheco soils are fine-loamy, mixed, superactive, thermic Fluvaquentic Haploxerolls.
This ecological site has been correlated with the following map units and soil components within the Santa Monica Mountains Soil Survey Area (CA692):
Map unit Component Percent
130 Camarillo 85
130 Pacheco 10
270 Pacheco 90
270 Camarillo 10
Table 4. Representative soil features
Surface texture (1) Silty clay
(2) Sandy loam
Family particle size (1) Loamy
Drainage class Poorly drained to somewhat poorly drained Permeability class Moderately slow to rapid Soil depth 59 – 80 in Available water capacity
(0-40in)7 – 11.3 in Calcium carbonate equivalent
(0-40in)0 – 10 % Electrical conductivity
(0-40in)4 – 11 mmhos/cm Sodium adsorption ratio
(0-40in)0 – 6 Soil reaction (1:1 water)
(0-40in)7.9 – 9 Ecological dynamics
This ecological site is associated with a coastal lagoon/ estuary system. The plant community is often called a tidal marsh or salt marsh. Mugu lagoon is the largest salt marsh in this survey area. These systems generally receive fresh water from small streams and groundwater. They also get inundated by high tides that come though the sand dune barrier. The opening to the ocean often migrates, causing shifts to the plant communities. The primary plant community is dominated by saltgrass (Distichlis spicata), pickleweed (Salicornia spp.), woodsorrel (Oxalis spp.), and big saltbush (Atriplex lentiformis). Several other species are also present. The plants present are physically adapted for this high salt zone. This site encompasses several zones of plant communities within the salt marsh. These zones are on a gradient from frequent to infrequent saltwater inundation.
Fire is not frequent in the salt marsh community. However, if the drier areas should burn, the rhizomes of saltgrass are far enough below the soil surface to protect them from fire.
The salt marshes have been disturbed in many areas by agricultural practices, such as creating ditches or beams to divert water from the fields, and draining pesticide rich run off to the marsh. Some areas have been filled for building structures.
Salt Marshes provide critical habitat for a diversity of terrestrial and aquatic animals, including birds, invertebrates, fish and seals. Many rare and endangered species are found only in coastal salt marshes.
Access to Mugu lagoon is limited because it is owned by the U.S. Naval Air Weapons Station. NRCS data is insufficient to determine a state and transition model for the salt marsh communities. It may be better to describe the community dynamics in relation to salt water inundation and hydrology, rather than by a disturbance regime.
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
Salt MarshCommunity 1.1
Salt MarshThe salt marsh plant community is dominated by saltgrass (Distichlis spicata), Pickleweed (Salicornia spp.), woodsorrel (Oxalis spp.), and quailbrush (Atriplex lentiformis spp. breweri). The Flora of the Santa Monica Mountains (Raven et al., 1986), lists the following species within the coastal salt marsh: Parish's glasswort (Arthrocnemum subterminale), alkali seaheath (Frankenia salina), shoregrass (Monanthochloe littoralis), marsh jaumea (Jaumea carnosa), turtleweed (Batis maritima), California sealavender (Limonium californicum), California seablite (Suaeda californica), and in the lower areas California cordgrass (Spartina foliosa). Saltmarsh birds-beak (Cordylanthus maritimus) is found in Mugu Lagoon, and is restricted to 4 populations in Southern California. It grows around the periphery of the salt marsh (Ball and Keeney).
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 (%) Grass/Grasslike1 Grasses 200–400 saltgrass DISP Distichlis spicata 200–400 – Forb2 Native Forbs 150–400 pickleweed SALIC Salicornia 150–350 – woodsorrel OXALI Oxalis 0–50 – 3 Non-native Forb 50–200 sweetclover MEOF Melilotus officinalis 50–150 – spiny sowthistle SOAS Sonchus asper 0–50 – Shrub/Vine4 Shrubs 0–200 quailbush ATLEB Atriplex lentiformis ssp. breweri 0–200 – Interpretations
Animal community
The salt marsh and estuary provide critical habitat for and abundance of waterfowl, waders, and shorebirds, including many rare, endangered or threatened species. Some of the rare birds that utilize Mugu Lagoon are mentioned below. The light-footed clapper rail (Rallus longirostris levipesis) is a rare non-migratory bird, associated with with California cordgrass (Spartina foliosa) plant communities. Snowy plovers (Charadrius alexandrinus nivosus) are year round residents at Mugu Lagoon, which nest on the nearby dunes. Least Tern (Sterna antillarum browni) is a migratory bird associated with coastal lagoons, bays and dunes. Belding’s Savannah Sparrow (Passerculus sandwichensis beldingi) is also a year round resident of coastal marshes. Brown pelican (Pelecanus occidentalis californicus) has nesting colonies in Mugu Lagoon (Ball and Keeney).
The Mugu Lagoon at NASPM is the third largest spring migration stopover habitat for shorebirds. The density of shorebirds during this migration ranges from 60,000 to 75,000 individuals (Ball and Keeney).
Mugu Lagoon is important haul out site for harbor seals.
The seeds of saltgrass are eaten by numerous species of waterfowl and small mammals. Saltgrass provides cover for small wildlife species (Houser, 2006).
Hydrological functions
Depth to water table is approximately three feet.
Supporting information
Other references
Ball, Barbara J.; and Keeney, Thomas W. Creation of Coverage Representing Ecological Sensitivity Categories on NAS Point Mugu, California. Online at: http://gis.esri.com/library/userconf/proc00/professional/papers/PAP862/p862.htm
Hauser, A. Scott. 2006. Distichlis spicata. 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/ [2008, January 17].
Raven, Peter H., Henry J. Thompson, and Barry A. Prigge. 1986. Flora of the Santa Monica Mountains, California. Second Edition. Southern California Botanists, Special Publication No. 2. University of California, Los Angeles.
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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