Ecological site group description

Provisional. A provisional ecological site description has undergone quality control and quality assurance review. It contains a working state and transition model and enough information to identify the ecological site.

Physiography

Hierarchical Classification
Major Land Resource Area (MLRA): 007X – Columbia Basin

LRU – Common Resource Areas (CRA):
7.1 – Sandy Missoula Flood Deposits
7.5 – Yakima Valley – Pleistocene Lake Basins

Site Concept Narrative:
Diagnostics:
Sandy is an upland ecological site occurring on sandy loam textured soils that are moderately deep to deep. The soils on the Sandy ecological site have carbonates at or near the surface, so available water for plants is limited.

Whereas, the surrounding sites are shrub steppe, the Sandy ecological site stands out because it is a grassland site. The Sandy ecological site is almost a monoculture of needle and thread in the Reference State and a monoculture of cheatgrass in the altered state. Shrubs are virtually, nonexistent and forbs are a minor component.

The Sandy and Sandy Loamy ecological sites both have a sandy loam soil texture. The difference is that the Sandy ecological site has carbonates up to the surface, while on Sandy Loam ecological site, the carbonates are not encountered until a depth of 18 inches or greater. Sandy Loam ecological site supports a shrub steppe community of Wyoming big sagebrush, bluebunch wheatgrass and needle and thread. Sandy ecological site, on the other hand, has a grassland community dominated by needle and thread.

The line between Sandy and Sandy loam ecological sites is often sharp. It is possible to stand with one foot on Sandy ecological site and the other on Sandy Loam ecological site.

Principle Vegetative Drivers:
The carbonates at or near the surface limits available water for plants, and thus, drives the grassland vegetative expression of the Sandy ecological site.

INFLUENCING WATER FEATURES
A plant’s ability to grow on a site and overall plant production is determined by soil-water-plant relationships
1. Whether rain and melting snow runs off-site or infiltrates into the soil
2. Whether soil condition remain aerobic or become saturated and become anaerobic
3. Water drainage and how quickly the soil reaches wilting point

Sandy ecological sites have less available water than Sandy loam ecological sites because the carbonates are at or near the soil surface. Soils are well drained and dry down quicker than adjacent Loamy ecological sites.

Physiographic features:
The landscape is part of the Columbia basalt plateau. The Sandy ecological site is commonly found on terraces and fan terraces, mesas, hillslopes, outwash plains, benches and plateaus.

Physiographic Division: Intermontane Plateau
Physiographic Province: Columbia Plateau
Physiographic Sections: Walla Walla Plateau Section

Landscapes: Basin and valleys
Landform: Terraces, terraces escarpments and alluvial flats

Elevation:
Range: 300 to 1,800 feet
Central tendency: 300 to 1,200 feet

Slope:
Total range: 0 to 60 percent
Central tendency: 10 to 55 percent

Aspect: Occurs on all aspects

Geology:
This is almost entirely underlain by Miocene basalt flows. Columbia River basalt is covered in most areas with as much as 200 feet of eolian, lacustrine, and alluvial deposits. This basin generally corresponds to the vast temporary lakes created by floodwaters from glacial Lakes Missoula and Columbia. Most of the fluvial and lacustrine sediments were deposited about 16,000 years ago, when an ice dam on the ancient Columbia River burst and when glacial Lake Missoula periodically emptied, creating catastrophic floods.

Climate

The climate across MLRA 007X is characterized by moderately cold, wet winters, and hot, dry summers, with limited precipitation due to the rain shadow effect of the Cascades. Seventy to seventy-five percent of the precipitation comes late-October through March as a mixture of rain and snow. Precipitation that comes after March is not as effective for plant growth. June through early-October can be dry. Freezing temperatures generally occur from late-October through early-April. Temperature extremes are -10 degrees Fahrenheit in winter and 110 degrees Fahrenheit in summer. Winter fog is variable and often quite localized, as the fog settles on some areas but not others.

Mean Annual precipitation
Range: 4 - 10 inches
Soil moisture regime is aridic.

Mean Annual Air Temperature
Range: 48 to 54 F
Central Tendency: 50 – 52 F
Soil temperature regime is mesic.

Frost-free period (days)
Total range: 140 to 200
Central tendency: 150 to 180
The growing season for Sandy is March through mid-June.

Soil features

Edaphic:
The Sandy ecological site occurs with Sandy Loam, Sands and Shallow Stony Sand ecological sites.

REPRESENTATIVE SOIL FEATURES
This ecological site’s soil components are dominantly Xeric taxonomic subgroup of Torriorthents and Haplocambids great groups of the Entisols and Aridisols taxonomic orders. Soils are dominantly very deep. Average available water capacity of about 3.5 inches (8.9 cm) in the 0 to 40 inches (0-100 cm) depth range.

Soil parent material is dominantly alluvium derived from mixed sources.

The associated soils are Finley, Neppel and similar soils.

Dominate soil surface is fine sandy loam to cobbly fine sandy loam.

Dominant particle-size class is coarse-silty and coarse loamy.

Fragments on surface horizon > 3 inches (% Volume):
Minimum: 0
Maximum: 2
Average: 0

Fragments within surface horizon > 3 inches (% Volume):
Minimum: 0
Maximum: 25
Average: 2

Fragments within surface horizon ≤ 3 inches (% Volume):
Minimum: 0
Maximum: 25
Average: 10

Subsurface fragments > 3 inches (% Volume)
Minimum: 0
Maximum: 30
Average: 10

Subsurface fragments ≤ 3 inches (% Volume):
Minimum: 0
Maximum: 35
Average: 25

Drainage Class: Dominantly well drained.
Water table depth: Dominantly greater than 60 inches

Flooding:
Frequency: None

Ponding:
Frequency: None

Saturated Hydraulic Conductivity Class:
0 to 10 inches: Moderately high and high
10 to 40 inches: Moderately high and high

Depth to root-restricting feature (inches):
Minimum: Dominantly greater than 60 inches
Maximum: Greater than 60

Electrical Conductivity (dS/m)
Minimum: 0
Maximum: 2

Sodium Absorption Ratio
Minimum: 0
Maximum: 0

Calcium Carbonate Equivalent (percent):
Minimum: 10
Maximum: 30

Soil Reaction (pH) (1:1 Water):
0 - 10 inches: 7.4 to 9.6
10 - 40 inches: 7.4 to 9.6

Available Water Capacity (inches, 0 – 40 inches depth)
Minimum: 2.1
Maximum: 5.1
Average: 3.5

Vegetation dynamics

ECOLOGICAL DYNAMICS:
Vegetation Dynamics:
Sandy ecological site produces about 400 to 700 pounds per acre of biomass annually.

The Sandy ecological site is a grassland site with needle and thread as the dominant plant. Needle and thread is a very drought tolerant perennial bunchgrass. It prefers excessively drained sandy and coarse textured gravelly loam soils. Needle and thread produces erect, unbranched stems about three feet in height. The seeds have a four to five-inch long twisted awn, and with wetting and drying the seed drills itself into the ground. Thus, needle and thread is one of the best natural seeders of all the native species.

The stability and resiliency of the reference communities is directly linked to the health and vigor of needle and thread. Research has found that the community remains resistant to medusahead if the site maintains at least 0.8 plants per square foot of mid-sized bunchgrass (K. Davies, 2008). These two grasses help hold the system together. As needle and thread plants decline, the ecosystem begins to unravel.

The natural disturbance regime for grassland communities is periodic lightning-caused fires. The fire return intervals (FRI) listed in research for sagebrush steppe communities is quite variable. Ponderosa pine communities have the shortest FRI of about 10 to 20 years (Miller). The FRI increases as one moves to wetter forested sites or to dries shrub steppe
communities. Given the uncertainties and opinions or reviewers, a mean of 75 years was chosen for Wyoming big sagebrush communities (Rapid Assessment Model). This would place the historic FRI for grassland steppe around 30 to 50 years.

Fire is not a major concern on this ecological site. There are no shrubs to lose to fire and burn severity is generally low to moderate because the Sandy ecological site is grassland. And needle and thread is pretty much fire tolerant as fire rarely burns into the crown of the plant.

Grazing is another common disturbance that occurs in this ecological site. Grazing pressure can be defined as heavy grazing intensity, or frequent grazing during reproductive growth, or season-long grazing (the same plants grazed more than once). As grazing pressure increases the needle and thread is replaced by cheatgrass.

Managing grasslands to improve the vigor and health of needle and thread begins with an understanding of the needs. New growth each year begins from basal buds. Needle and thread also reproduces via seed and needs to produce viable seed on a regular basis.

Repeated critical period grazing (boot stage through seed formation) is especially damaging. Over several years each native bunchgrass pasture should be rested during the critical period two out of every three years (approximately April 1 through June 30). And each pasture should be rested the entire growing-season every third year (approximately
March 1 – June 30).

In the spring each year it is important to monitor and maintain an adequate top growth: (1) so plants have enough energy to replace basal buds annually, (2) to optimize regrowth following spring grazing and (3) so needle and thread can produce viable seed.

Needle and thread remains competitive if:
(1) Basal buds are replaced annually,
(2) Enough top-growth is maintained for growth and seed production, and
(3) The timing of grazing and non-grazing is managed over a several-year period. Careful management of late spring grazing is especially critical

For more grazing management information refer to Range Technical Notes found in Section I Reference Lists of NRCS Field Office Technical Guide for Washington State.

In Washington, needle and thread-Indian ricegrass communities provide habitat for a variety of upland wildlife species.

Supporting Information:

Associated Sites:
Sandy ecological site is associated with Sandy Loam, Sands and Shallow Stony Sand ecological sites.

Similar sites:
Sandy is a grassland ecological site dominated by needle and thread. There are no similar sites in MLRAs 006X, 007X, 008X or 009X.

Inventory Data References (narrative)
Data to populate Reference Community came from several sources: (1) NRCS ecological sites from 2004, (2) Soil Conservation Service range sites from 1980s and 1990s, (3) Daubenmire’s habitat types, and (4) ecological systems from Natural Heritage Program

State Correlation: Washington
 
References:

Boling M., Frazier B., Busacca, A., General Soil Map of Washington, Washington State University, 1998

Daubenmire, R., Steppe Vegetation of Washington, EB1446, March 1968

Davies, Kirk, Medusahead Dispersal and Establishment in Sagebrush Steppe Plant Communities, Rangeland Ecology & Management, 2008

Environmental Protection Agency, map of Level III and IV Ecoregions of Washington, June 2010

Miller, Baisan, Rose and Pacioretty, “Pre and Post Settlement Fire regimes in mountain Sagebrush communities: The Northern Intermountain Region

Natural Resources Conservation Service, map of Common Resource Areas of Washington, 2003

Rapid Assessment Reference Condition Model for Wyoming sagebrush LANDFIRE project, 2008

Rocchio, Joseph & Crawford, Rex C., Ecological Systems of Washington State. A Guide to Identification. Washington State Department of Natural Resources, October 2015. Pages 156-161 Inter-Mountain Basin Big Sagebrush.

Rouse, Gerald, MLRA 8 Ecological Sites as referenced from Natural Resources Conservation Service-Washington FOTG, 2004

Soil Conservation Service, Range Sites for MLRA 8 from 1980s and 1990s

Tart, D., Kelley, P., and Schlafly, P., Rangeland Vegetation of the Yakima Indian reservation, August 1987, YIN Soil and Vegetation Survey

Site Development and Testing Plan
Future work, as described in a Project Plan, to validate the information in this Provisional Ecological Site Description is needed. This will include field activities to collect low, medium and high intensity sampling, soil correlations, and analysis of that data. Annual field reviews should be done by soil scientists and vegetation specialists. A final field review, peer review, quality control, and quality assurance reviews of the ESD will be needed to produce the final document.
Annual reviews of the Project Plan are to be conducted by the Ecological Site Technical Team.

Major Land Resource Area

MLRA 007X
Columbia Basin

Subclasses

• R007XY449WA–Sandy

Stage

Provisional

Contributors

Provisional Site Author: Kevin Guinn
Technical Team: R. Fleenor, W. Keller, K. Bomberger, K. Paup-Lefferts