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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 Not specified
Shrub (1) Adenostoma fasciculatum
Herbaceous (1) Selaginella bigelovii
Physiographic features
This site is located on steep, exposed slopes between 20 to 70% at elevations ranging from 984 to 2493. It is most commonly found on south-facing slopes, but can also be found on west-facing slopes.
Table 2. Representative physiographic features
Landforms (1) Hill
Elevation 984 – 2493 ft Slope 20 – 70 % Aspect SE, S, SW Climatic features
The average annual precipitation in MLRA 15 is from 6 to 20 inches (150 to 510 millimeters) in the area south of San Francisco, and snowfall is rare. The north half of this area can be divided into two rainfall and snowfall zones. The southern half north of San Francisco has an average annual precipitation from 18 to 40 inches (460 to 1,015 millimeters) and snowfall is rare. In the north half, average annual precipitation is from 40 to 79 inches per year (1,015 to 2,010 millimeters) and snowfall is common. Precipitation is evenly distributed throughout fall, winter, and spring but is very low in summer. Coastal areas receive some moisture from fog in summer. Most of the rainfall occurs as low to moderate intensity, Pacific frontal storms during the winter from October to May. The average annual temperature is from 51 to 66 degrees F (10 to 19 degrees C), decreasing from south to north. The average frost-free period is 275 days (180 to 365 days), decreasing with elevation and from south to north.
At Pinnacles National Monument, the average annual precipitation is 17 inches with a range between 17 and 19 inches, mostly from rain in the winter months from November through April. The average annual air temperature is between 59 and 63 degrees Fahrenheit, and the frost-free period (>32F) is 190 to 210 days.
NOTE: Data collected for monthly precipitation and temperatures is only from one climate station.Table 3 Representative climatic features
Frost-free period (average) 210 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
Soil features
The soil for this ecological site is young, and very shallow and is classified as a loamy-skeletal Lithic Xerorthent. It is residuum derived from rhyolite, primarily formed from the mineral debris that washes down the face of the rhyolite bedrock outcroppings.
The soil for this site is unique, because the bushy spikemoss (Selaginella bigelovii) plays a key role in its development. The tiny plant and it's shallow roots, capture the mineral debris that's being washed over the rocks and stabilize them by enriching them with organic matter and binding the sediments. The result is a very shallow soil (4-10 inches), with extremely gravelly sandy loam over hard bedrock. They have high runoff potential, with moderate to moderately rapid permeability, and they're well-drained with very low available water capacity (avg. 0.4 inches).
This ecological site occurs on the following soil components in the Pinnacles National Monument soil survey.
SSA MU Symbol Component
CA069 104 Burgundy
CA069 109 Burgundy
CA069 110 Burgundy
CA069 110 KnuckleTable 4. Representative soil features
Surface texture (1) Extremely gravelly sandy loam
(2) Gravelly sandy loam
Family particle size (1) Sandy
Drainage class Well drained to somewhat excessively drained Permeability class Moderate to moderately rapid Soil depth 4 – 12 in Surface fragment cover <=3" 25 – 65 % Surface fragment cover >3" 5 – 20 % Available water capacity
(0-40in)0.3 – 0.5 in Electrical conductivity
(0-40in)0 – 1 mmhos/cm Sodium adsorption ratio
(0-40in)Not specified Soil reaction (1:1 water)
(0-40in)5 – 7.3 Subsurface fragment volume <=3"
(Depth not specified)30 – 65 % Ecological dynamics
This ecological site is characterized by a heavy dominance of bushy spikemoss (Selaginella bigelovii). Besides the heavy dominance of bushy spikemoss (Selaginella bigelovii), there are scattered patches of chamise (Adenostoma fasciculatum), California buckwheat (Eriogonum fasciculatum), foothill pine (Pinus sabiniana), and needlegrasses (Nassella spp.). Bushy spikemoss has played a major role in the formation of this site by capturing sediment as its being washed off the rock ledges and outcroppings. The result is a very shallow soil, with extremely gravelly sandy loam over hard bedrock.
State and transition model
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Click on state and transition labels to scroll to the respective textEcosystem states
State 1 submodel, plant communities
State 1
Bushy spikemossCommunity 1.1
Bushy spikemossThis ecological site is characterized by a heavy dominance of bushy spikemoss (Selaginella bigelovii). It is found on exposed positions, dominated by rock outcroppings and shallow soils. It’s found generally on south aspects, with slopes ranging from 20 to 70% and elevations ranging from 984 to 2493 feet. Besides the heavy dominance of bushy spikemoss (Selaginella bigelovii), there are scattered patches of chamise (Adenostoma fasciculatum), California buckwheat (Eriogonum fasciculatum), foothill pine (Pinus sabiniana), and needlegrasses (Nassella spp.). Bushy spikemoss has played a major role in the formation of this site by capturing sediment as its being washed off the rock ledges and outcroppings. The result is a very shallow soil, with extremely gravelly sandy loam over hard bedrock.
Additional community tables
Table 5. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Interpretations
Supporting information
Contributors
K. Moseley
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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