Natural Resources
Conservation Service
Ecological site R010XC044OR
SR South Schist 9-12 PZ
Last updated: 12/13/2023
Accessed: 12/06/2024
General information
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.
MLRA notes
Major Land Resource Area (MLRA): 010X–Central Rocky and Blue Mountain Foothills
This MLRA is characterized by gently rolling to steep hills, plateaus, and low mountains at the foothills of the Blue Mountains in Oregon and the Central Rocky Mountains in Idaho. The geology of this area is highly varied and ranges from Holocene volcanics to Cretaceous sedimentary rocks. Mollisols are the dominant soil order and the soil climate is typified by mesic or frigid soil temperature regimes, and xeric or aridic soil moisture regimes. Elevation ranges from 1,300 to 6,600 feet (395 to 2,010 meters), increasing from west to east. The climate is characterized by dry summers and snow dominated winters with precipitation averaging 8 to 16 inches (205 to 405 millimeters) and increasing from west to east. These factors support plant communities with shrub-grass associations with considerable acreage of sagebrush grassland. Big sagebrush, bluebunch wheatgrass, and Idaho fescue are the dominant species. Stiff sagebrush, low sagebrush, and Sandberg bluegrass are often dominant on sites with shallow restrictive layers. Western juniper is one of the few common tree species and since European settlement has greatly expanded its extent in Oregon. Nearly half of the MLRA is federally owned and managed by the Bureau of Land Management. Most of the area is used for livestock grazing with areas accessible by irrigation often used for irrigated agriculture.
Classification relationships
U.S. National Vegetation Classification Standard (NVCS)
Group: G310. Intermountain Semi-Desert Steppe & Shrubland
Alliance: A1032. Glossopetalon spinescens Shrubland Alliance
Association: CEGL001100. Glossopetalon spinescens var. aridum / Pseudoroegneria spicata Shrubland
Ecological site concept
In reference condition, this site supports a plant community dominated by a sparse community of bluebunch wheatgrass (Pseudoroegneria spicata) with a scattered layer of spiny greasebrush (Glossopetalon spinescens) often present. This site occurs on rocky canyon walls and south-facing side slopes of hills and ravines with annual precipitation ranging from 9 to 12 inches. The soils of this site are typified by moderately deep, extremely channery loam derived from schist with areas of rock outcrop. The soil climate of this site is frigid and aridic. Ecological dynamics of this site were historically driven by climate and fire cycles. As a dry canyon site, this site is vulnerable to invasion by exotic annual bromes (Bromus spp.) if the disturbance regime is altered.
This is a provisional ecological site whose accelerated development from a draft site was undertaken with little to no field verification and is subject to extensive review and revision before final approval. All data herein was developed using existing information and literature and should be considered provisional and contingent upon field validation prior to use in conservation planning.
Associated sites
R010XC052OR |
SR Shallow South Schist 9-12 PZ Adjacent shallow slopes |
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Similar sites
R010XC052OR |
SR Shallow South Schist 9-12 PZ Shallow soils |
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Table 1. Dominant plant species
Tree |
Not specified |
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Shrub |
(1) Glossopetalon spinescens |
Herbaceous |
(1) Pseudoroegneria spicata ssp. spicata |
Click on box and path labels to scroll to the respective text.
T1A | - | Introduction of non-native species from vectors such as grazing animals, vehicles or humans. |
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T2A | - | Severe or continuous disturbance in the presence of non-native annual species (e.g. catastrophic fire and soil disturbing treatments or inappropriate grazing management resulting in utilization of perennial bunchgrasses that impacts the plant’s ability to recover) |
R3A | - | Seeding with native perennial bunchgrasses (or non-native perennial grasses in some cases); mechanical, biological or chemical treatment of exotic species; and alteration of grazing management. |