Common (Translated Scientific) Name: Brittlebush - (Arizona Joint-fir, Nevada Joint-fir) Shrubland
Hierarchy Level: Association
Type Concept: This shrubland association has been described from the inner gorge of Grand Canyon National Park in northwestern Arizona. Elevation ranges from 610-1340 m. Stands occur on south-facing colluvial slopes below cliffs. Sites are predominately steep to moderate slopes, often talus with frequent rock outcrops. Substrate is shallow, rocky soil derived from limestone, sandstone, shale or igneous parent materials. Stands have a sparse (less than 20% cover), short woody canopy (less than 1 m tall) that is dominated by the xeromorphic evergreen shrubs Encelia farinosa and the xeromorphic evergreen shrubs Ephedra nevadensis and Ephedra viridis. Other common shrubs and dwarf-shrubs may include Acacia greggii, Gutierrezia sarothrae, or Lycium andersonii. The sparse herbaceous layer is composed of scattered forbs such as Galium stellatum, Machaeranthera pinnatifida, Eriogonum inflatum, and the introduced annual grass Bromus rubens. Succulents are common and include Opuntia basilaris, Opuntia erinacea, Opuntia phaeacantha, Echinocereus engelmannii, Echinocactus polycephalus, Ferocactus cylindraceus (= Ferocactus acanthodes), and Agave utahensis. Extent outside the park is not known. This association appears to be restricted to these inner-canyon habitats in the Grand Canyon. Disturbance from rockslides may be important in maintaining this successional type. Shrublands with similar species composition have been reported from California, but survey and classification work are needed to determine if they represent the same association as this.
Diagnostic Characteristics: No Data Available
Rationale for Nominal Species or Physiognomic Features:
Classification Comments: No Data Available
Similar NVC Types:
Geographic Range: Assuming this association is restricted to the Grand Canyon, then its range is less than 5000 square km. Occurrence of stands outside the inner gorge of Grand Canyon National Park is unknown.
States/Provinces: AZ, CA?
|US Forest Service Ecoregions (1994/1995)|
Colorado Plateau Semi-Desert Province
Confident or certain
Mojave Desert Section
Confident or certain
Greasons: This shrubland association occurs extensively in the inner gorge of Grand Canyon National Park, Arizona. Stands are found predominately on colluvial slopes with southern aspects and may be endemic to the park. Disturbance from rockslides may be important in maintaining this successional type. Within the park, stands are protected, however, condition has declined in some stands because of the abundance of Bromus rubens, an introduced annual grass. The extent and status of this vegetation outside the park is not known. More survey work is needed, especially on colluvial slopes in mountainous areas in the Mojave Desert, which may have similar vegetation.