Name:
Sporobolus airoides Herbaceous Alliance
Reference:
Western Ecology Working Group of...
Description:
This grassland alliance occurs in the western and southern Great Plains, Great Basin, and across the southwestern United States from Texas to California. It is reported from saline habitats in the Central Valley and in valleys and lower slopes of transmontane California from the Modoc Plateau to the Owens Valley. Elevations range from near sea level to 2100 m, but typically from 1000-1700 m. Climate is arid to semi-arid. Stands occur in a wide variety of lowland sites, such as stream terraces, swales, interdune basins, and alluvial flats. This alliance in not defined by a flood regime, but the soil often has a high water table because of land position and impermeable subsurface horizons. Soils are non-saline to moderately saline and usually alkaline. Soil surface textures are sandy to clayey. The soils morphology often includes a claypan, caliche layer or other subsurface horizon that impedes water movement. Parent material is typically alluvium derived from limestone, shale, or sandstone. The vegetation is characterized by a sparse to moderately dense graminoid layer of medium-tall bunch grasses with smaller densities of short grasses and forbs. Widely scattered (<10% cover) xeromorphic or halophytic shrubs and dwarf-shrubs may also be present. Sporobolus airoides is the dominant or codominant grass. Typical codominant grasses include Muhlenbergia porteri, Panicum obtusum, or Scleropogon brevifolius. Not included in this alliance are stands codominated by Achnatherum hymenoides, Bouteloua gracilis, Distichlis spicata, Pleuraphis jamesii (= Hilaria jamesii), or Hordeum jubatum, although they may be present in small amounts. Other common grasses are Buchloe dactyloides, Pascopyrum smithii, Hordeum pusillum, and Sporobolus cryptandrus. Forbs and shrubs are typically sparse. Common forb associates are Chaetopappa ericoides and species of Sphaeralcea, Machaeranthera, Ratibida, Helianthus, and other Asteraceae spp. Scattered shrubs may include Allenrolfea occidentalis, Atriplex canescens, Chrysothamnus spp., and Sarcobatus vermiculatus. Species of Salicornia and Suaeda occur in more saline habitats. The dwarf-shrub Gutierrezia sarothrae is common in many stands. Some stands have significant amounts of prickly pear and cholla cacti (Opuntia spp.).
Accession Code:
VB.CC.19677.SPOROBOLUSAIROI
Plot-observations of this Community Concept:
0
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