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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 (1) Populus fremontii
(2) Platanus racemosaShrub (1) Salix laevigata
(2) Salix exiguaHerbaceous (1) Carex
(2) JuncusPhysiographic features
This site is found on flat to gradually sloping surfaces along waterways. Slopes range from 0 to 50% on elevations from 656 to 1968, and can be found on all aspects.
Table 2. Representative physiographic features
Landforms (1) Stream terrace
(2) Flood plain
(3) Hill
Flooding duration Long (7 to 30 days) Flooding frequency None to frequent Ponding duration Long (7 to 30 days) Ponding frequency None to frequent Elevation 656 – 1968 ft Slope 0 – 50 % Ponding depth 0 – 12 in Water table depth 30 – 59 in Aspect Aspect is not a significant factor 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 61 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
Hydrologic groups B and C.
Soil features
The primary soils for this site are found on nearly level to gently sloping narrow floodplains and stream terraces along Chalone Creek and in Bear Valley. There are three phases to these soils, one phase is found on floodplains and frequently flooded, one phase that rarely floods but has a seasonally high water table, and one phase that is found on stream terraces at the base of hills where seeps emerge. They are all Oxyaquic Haploxerolls with gravelly and sandy alluvium parent materials from rhyolite and granite. They are coarse textured soils with low water storage capacity and low fertility. The frequently flooded phase is classified as a hydric soil due to its seasonal flooding, causing the soil to be deficient in oxygen at the surface. The rarely flooded phase is found on the lowest stream terrace, several feet higher than the bottom floodplain and usually holds water within 4 feet of the soil surface, making the upper part of the soil well-aerated most of the year. A typical soil profile consists of pale, stratified sandy loam to very gravelly loamy coarse sand. The third phase of Oxyaquic Haploxerolls are saturated and anaerobic for most of the year, due to their location at the base of hills where water is continually collecting as it runs off the hillslopes. They are hydric soils with drab colors or mottles. This type of soil typically supports vegetation that can adapt to seasonal to year-round anaerobic conditions, yearly disturbances, and sediment deposition.
Another soil series that is associated with this site is the Still series. These soils are found several feet above the stream on nearly level to moderately sloping stream terraces that are no longer affected by flooding or seasonally high water tables. They are well drained, alluvium soils and are derived from volcanic and sedimentary rock. Due to alterations to the stream channels in this area, the channel has become deeply incised, lowering the water table far below the root zones and removing annual sediment additions to the soil creating a profile with buried, stratified horizons, dark from organic matter. The Still soils are found some distance from the stream channel where flood waters likely pooled allowing for finer textures, primarily clays, to settle out. This has created a soil that is a dark, sandy loam over stratified silty clay loam to gravelly clay loam to a depth over 60 inches. This type of soil typically supports herbaceous species, but can support shrubs and trees that are able to utilize water deep into the soil profile, such as oaks and sycamores.
The upper canyon reaches of the riparian areas are a mixture of Oxyaquic Haploxerolls, Still, and also in mapunit 131, a significant amount of Firstsister soils. Firstsister soils are found in the shaded canyons where they conserve soil moisture and are mostly composed of topsoil additions from the soils found above on the hillslopes. They are very deep soils, dark and enriched with organic matter throughout the depth of the soil, resulting in a profile that is uniform, with loose extremely channery loam or extremely channery sandy loam textures to more than 60 inches deep. This type of soil typically supports trees and shade-tolerant shrubs.
This ecological site occurs on the following soil components in the Pinnacles National Monument soil survey.
SSA MU Symbol Component name
CA069 113 Oxyaquic Haploxerolls
CA069 117 Still
CA069 119 Oxyaquic Haploxerolls
CA069 128 Still
CA069 128 Oxyaquic Haploxerolls
CA069 131 Firstsister
CA069 131 Oxyaquic Haploxerolls
CA069 132 Oxyaquic Haploxerolls
CA069 134 Oxyaquic Haploxerolls
CA069 135 Oxyaquic Haploxerolls
CA069 136 Oxyaquic HaploxerollsTable 4. Representative soil features
Surface texture (1) Fine sandy loam
(2) Gravelly loamy coarse sand
(3) Sandy loam
Drainage class Somewhat poorly drained to well drained Permeability class Slow to moderately rapid Soil depth 80 – 0 in Surface fragment cover <=3" 0 – 15 % Surface fragment cover >3" 25 – 45 % Available water capacity
(0-40in)2.4 – 6.1 in Electrical conductivity
(0-40in)0 – 2 mmhos/cm Sodium adsorption ratio
(0-40in)0 – 5 Soil reaction (1:1 water)
(0-40in)4.5 – 8.4 Subsurface fragment volume <=3"
(Depth not specified)0 – 80 % Subsurface fragment volume >3"
(Depth not specified)0 – 40 % Ecological dynamics
The reference plant community for this site varies depending on its location throughout Pinnacles National Monument. The alluvial portions of the riparian zone are dominated by Fremont’s Cottonwood (Populus fremontii), California sycamore (Platanus racemosa), and several willows (Salix laevigata, Salix laseolepis, and Salix exigua). The understory species varies considerably and is driven by annual flood events, sediment deposition and removal, and the overall hydrology of the site. The upper, canyon stretches of the riparian areas are dominated by primarily by California or coast live oak (Quercus agrifolia) and California sycamore, with an understory dominated by California buckeye (Aesculus californica), poison oak (Toxicodendron diversilobum), California ash (Fraxinus dipleta), hollyleaf cherry (Prunus ilicifolia), hollyleaf redberry (Rhamnus ilicifolia), currents (Ribes spp.), California blackberry (Rubus ursinus), ferns (Pteridinium spp.), sedges (Carex spp.), and rushes (Juncus spp.).
Rivers and streams are characterized by a one-way flow of water, which tends to transport nutrients, sediments, pollutants, and organisms downstream. They are dynamic systems with highly variable flows during the course of a year, which dictates the shape of the stream and patch dynamics of the vegetation that establish during the year. This dynamic system of constantly flowing water also allows materials to be constantly added to the system, which includes organic matter and sediments, woody debris accumulations and nutrients and organisms that cycle through the entire system helping to improve the overall function of the stream and productivity of the vegetation it supports (NRC 1992).
Annual disturbance is crucial to the plant communities that are found in riparian areas, affecting the overall structure and function of the system. It maintains each portion of a stream, flushing the gravel beds of the fine sediment build-up, while creating new open sandbars and fine sediment pockets for other species to establish and colonize. This system functions best in dynamic equilibrium at a landscape-scale, meaning that the local features that are created will undergo changes through time and eventually disappear, while the overall pattern remains constant. Oxbows are created and offer habitat and structure in the community for certain periods of time, however a major flood event can come through one year and cut off the oxbow, creating a patchy pocket that will begin to dry up over time, shifting the vegetation to species that function under more stable, less anaerobic conditions. Somewhere else a new oxbow is created, opening up that habitat to new, pioneering species that are adapted to the anaerobic conditions and new disturbances (NRC 1992).
This patchy nature is illustrated as lateral structure and vertical dimensions within the main channel, as well as the unvegetated and vegetated channel borders and floodplain habitats. Within each of the border and floodplain areas, the lateral structure is seen in distinct patches, usually determined by small differences in land elevation that determine the period of inundation and soil saturation. The vertical structure is seen in the canopy layers as they go from sedges, rushes, and grasses at the lowest level, to low-growing shrubs and vines, to taller shrubs like willows, and finally to trees. This type of structure offers habitat to a significant array of wildlife species.
These stream communities, when functioning naturally, have the ability to be more resistant to certain types of disturbances and may recover more quickly than most other types of systems. They are adapted to the dynamic equilibrium and have the capability to handle drastic changes that may occur from year to year. Species found in these stream habitats are better able to recolonize a barren reach since they have evolved with the disturbances and are adapted to them and often times the seed source is readily available after the disturbance has occurred. There are other circumstances where an area may be more capable of avoiding or surviving a disturbance in the main channel by colonizing an area that is less impacted by the disturbance (NRC 1992).
The structure and function of a stream or river system is vital to its success and once the hydrology is manipulated, this equilibrium becomes unbalanced and the stream loses its function and structure. Rivers and streams are not uniform environments and when they lose the annual disturbance and recharge, the plant communities shift and change becoming more uniform and can eventually begin to fail as a system. The water tables drop, the stream begins to straighten or channelize, and the system becomes more vulnerable to invasion by non-natives or upland species, streambank erosion, sediment loading, and loss of critical wildlife habitat.
California sycamore (Platanus racemosa)
California buckeye (Aesculus californica)
Fremonts’ Cottonwood (Populus fremontii)
Willows (Salix spp.)
Valley oak (Quercus lobata)
Coast live oak (Quercus agrifolia)
Interior live oak (Quercus wislizeni)
Mule’s fat (Baccharis salicifolia)
Coyotebrush (Baccharis pilularis)
Blackberry (Rubus spp.)
Elderberry (Sambucus spp.)
Mugwort
Senecio
Chenopods
Poison oak (Toxicodendron diversilobum)
Sedges:
C. barbarae
C. brevicaulis
C. serratodens
Cyperus difformis
Cyperus eragrostis
Cyperus erythrorhizos
Cyperus niger
Cyperus squarrosus
Eleocharis macrostachya
Eleocharis parishii
Eleocharis rostellata
Scirpus acutus
Scirpus americanus
Scirpus californicus
Scirpus microcarpus
Scirpus pungens
Baltic rush (Juncus balticus)
Toad rush (Juncus bufonius)
Juncus effusus
Juncus phaeocephalus
Juncus xiphiodes
Chlorogalum pomeridianum (soap plant)
Ferns (Pteridium spp.)
State and transition model
Custom diagramStandard diagram
Figure 3. Riparian Areas
More interactive model formats are also available. View Interactive Models
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 2 submodel, plant communities
State 3 submodel, plant communities
State 4 submodel, plant communities
State 1
Reference State - Colluvial reachesCommunity 1.1
Reference State - Colluvial reachesThis plant community occurs in the narrow canyons on the East side of Pinnacles National Monument along Bear Creek in mapunit 131.
State 2
Reference State - Alluvial reachesCommunity 2.1
Reference State - Alluvial reachesThis is the reference plant community for this ecological site and it is found primarily downstream in the alluvial floodplains where sediment deposition is greatest and disturbances to the system occur regularly.
Fremont cottonwood (Populus fremontii) is one of the dominant species in this plant community, acting as both a pioneer species and a highest seral species as well. It is a fast-growing, shade-intolerant, obligate seeder that requires flood scour disturbances in order to recolonize and establish. Cottonwoods have wind dispersed seeds that require open, freshly deposited sediment near the water’s edge left by newly receding floodwaters for suitable habitat. These sites are crucial for seedling development, as they offer subsurface water during the growing season for the roots to grow and establish.
Other species that are associated with Fremont cottonwood and are well-adapted to these disturbances include alders, red willow, arroyo willow, narrow-leaved willow, and mule’s fat (Baccharis salicifolia). These species are all physiologically adapted to anaerobic soil conditions, fluctuating water depths, seeds that can be spread by wind and water, vegetative spreading, as well as the ability to absorb water velocity and force. Mule’s fat seems to do best in some of the areas with larger cobbles and coarse textures that dry most rapidly, because their roots are able to grow at a rate that allows them to continue to have access to the water as it drops. This allows mule’s fat to find habitat even in ephemeral streams, thus mule’s fat can be found all the way into the actual stream channel of many stretches of a stream. Willows still require a sufficient amount of moisture in the water table, so they are often found in the sandy portions of the stream where waters have receded from the flooding, but underground water is still accessible to the roots.State 3
State 2 - Alluvial reachesCommunity 3.1
State 2 - Alluvial reachesThis is an upland community.
State 4
Invaded State - Alluvial reachesCommunity 4.1
Invaded State - Alluvial reachesThis invaded state has occurred due to heavily incised channels and a significant drop in the water table.
Additional community tables
Table 5. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 6. Community 2.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 7. Community 3.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 8. Community 4.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Interpretations
Other information
Restoration:
Sandbar willow's ability to rapidly colonize disturbed sites makes it very useful for streambank stabilization projects. Cuttings are preferred for use in revegetating disturbed riparian areas because they quickly stabilize disturbed alluvium, which allows other plants to become established. Unrooted willow stem cuttings (slips) should be planted on sites that provide sufficient moisture to start and maintain growth through the growing season [56]. Since willows are sensitive to
both competition and shading, dense tall grasses will reduce transplant survival [47] and may need to be removed by cutting or by herbicide application [34]. Although harder to plant, rooted stock is recommended
because it has higher survival rates [47,58]. Slips should be obtained from local native stands. Cuttings should be planted 12 inches (30 cm) deep, with 8 inches (20 cm) left above ground [47]. Planting deep allows for more rooting surface to extract soil moisture and higher amounts of carbohydrates as stored food reserves [47,58]. Sandbar willow cuttings root along the entire length of the stem, with roots appearing in about 10 days [23,47]. If serious streambank erosion has caused a nearly verticle cut bank, reshaping of the slope may be needed to enhance success of transplants; reshaping is not necessary if, through protective measures, existing vegetation is able to stabilize the site [47,58]. Under any method of revegetation, sites should be fenced to protect them from grazing and trampling.
Supporting information
Inventory data references
RR-01 - % and lbs Ocular estimates at Chalone Creek, Bear Creek, and creek on the West side.
Other references
FEIS: POFR, PLRA, Salix.
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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