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Conservation Service

Ecological site R014XC008CA

LOAMY BOTTOMLAND

Accessed: 08/17/2026

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General information

Draft. A draft ecological site description is either incomplete or has not undergone quality control and quality assurance review.

Table 1. Dominant plant species

Tree	(1) Quercus douglasii (2) Quercus agrifolia
Shrub	(1) Quercus berberidifolia
Herbaceous	(1) Bromus hordeaceus (2) Erodium

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Physiographic features

This site occurs inland on gently sloping alluvial fans and terraces. Slopes range from 2 to 9%, with elevations ranging from 10 to 300 feet.

Table 2. Representative physiographic features

Landforms	(1) Alluvial fan (2) Terrace
Elevation	10 – 300 ft
Slope	2 – 9 %
Aspect	Aspect is not a significant factor

Climatic features

Average rainfall is 25 to 35 inches. Climatic pattern is typically Mediterranean with most rain falling in the winter and spring.

Frost-free season is 250 to 280 days. The growing season depends upon the rainfall but generally is from December to April. The growing season may start as early as November. Average annual air temperature ranges from 60 to 65 degrees F.

Table 3 Representative climatic features

Frost-free period (average)	280 days
Freeze-free period (average)	0 days
Precipitation total (average)	40 in

Bar

Line

Figure 1. Monthly precipitation range

Bar

Line

Figure 2. Monthly average minimum and maximum temperature

Soil features

The soils that characterize this site are very deep, well drained gravelly loams to loams stratified or with gravelly clay loam and sandy clay loam subsoils. They are underlain by mixed alluvium from sedimentary rock. Available water capacity ranges from moderate to high.

This ecological site is associated with the map units and soil components in the following soil surveys. Future updates to the soil survey(s) may affect these associations.

PEC - Ballard gravelly loam, 2-9% slopes

Table 4. Representative soil features

Surface texture	(1) Gravelly loam (2) Gravelly clay loam
Family particle size	(1) Loamy
Drainage class	Well drained
Permeability class	Moderate
Soil depth	80 – 0 in
Available water capacity (0-40in)	5.5 in
Soil reaction (1:1 water) (0-40in)	5.6 – 6.5
Subsurface fragment volume <=3" (Depth not specified)	24 – 28 %
Subsurface fragment volume >3" (Depth not specified)	2 %

Ecological dynamics

State and transition model

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

Ecosystem states

1. Plant Community 1.1

State 1 submodel, plant communities

1.1. Plant Community 1.1

State 1
Plant Community 1.1

Community 1.1
Plant Community 1.1

This plant community consists of annual grasses, forbs and scattered oaks. Dominant species are soft chess (Bromus hordeaceous), Italian ryegrass (Lolium perenne var. multiflorum), filaree (Erodium spp.), and blue oak (Quercus douglassi) and California/coast live oak (Quercus agrifolia).

Regression due to mismanaged use by livestock and wildlife results in a decrease in preferred perennial and annual grasses and forbs and an increase in cheeseweed, yellow starthistle, and mustard. Overuse by livestock and wildlife will also result in the loss of seedling scrub oaks.

Annual production lbs./acre:

Favorable - 2900
Normal - 2100
Unfavorable - 1100

Figure 3. 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	715	1365	1885
Forb	385	735	1015
Total	1100	2100	2900

Additional community tables

Table 6. Community 1.1 plant community composition

Group	Common name	Symbol	Scientific name	Annual production ()	Foliar cover (%)
Grass/Grasslike
1				40–70
Forb
2				30–65
Tree
3				0–5

Interpretations

Animal community

There is good potential for improving the plant community on this site through reseeding and proper management. The plants selected for seeding should meet the seasonal requirements of livestock and wildlife. In unfavorable years, forage production will be very low due to low AWC.

Deer utilize forbs and grass on this site during early spring. Deer also lay down in tall grass during the day. Quail, dove, rodents and other small mammals, raptors, and songbirds utilize this site. Form ponds provide limited summer drinking water for wildlife.

Hydrological functions

Soils in this site are in hydrologic group B. The runoff curve for range in good condition is 61.

Recreational uses

This site provides opportunity for picnics, horseback riding, hikin, bird watching and general open space aesthetics.

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

Number and extent of rills:
Presence of water flow patterns:
Number and height of erosional pedestals or terracettes:
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
Number of gullies and erosion associated with gullies:
Extent of wind scoured, blowouts and/or depositional areas:
Amount of litter movement (describe size and distance expected to travel):
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
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:
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
Average percent litter cover (%) and depth ( in):
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
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 plant reproductive capability:

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