Name:
Larrea tridentata - Ambrosia dumosa Bajada & Valley Desert Scrub Alliance
Reference:
NatureServe Biotics 2019
Description:
This widespread alliance occurs in the Mojave, Sonoran and Colorado deserts and extends north into the transition zone with the Great Basin. The vegetation is characterized by an open, xeromorphic shrub layer codominated by <i>Larrea tridentata</i> and <i>Ambrosia dumosa</i>. Cover of either species does not exceed the other by more than twice, and no other species greatly exceeds the cover of both combined. Other desert shrubs and dwarf-shrubs may be present to codominant, including <i>Atriplex confertifolia, Atriplex hymenelytra, Ephedra funerea, Ephedra nevadensis, Hymenoclea salsola, Krameria grayi, Krameria erecta, Lycium andersonii, Cylindropuntia ramosissima, Psorothamnus arborescens, Psorothamnus fremontii, Salazaria mexicana, Senna armata</i>, and many others. If <i>Encelia farinosa</i> or <i>Yucca schidigera</i> is present, cover is low (<1-2% cover). Occasional emergent <i>Fouquieria splendens</i> or <i>Yucca brevifolia</i> and herbaceous species such as <i>Croton californicus, Eriogonum inflatum, Echinocactus polycephalus, Galium angustifolium</i>, or <i>Pleuraphis rigida</i> may also be present. Abundant annuals may be seasonally present. Stands occur on alluvial fans, bajadas, upland slopes, piedmonts and minor washes. Sites are gentle to moderately sloping. Substrates are typically well-drained, sandy soils derived from colluvium or alluvium. A pebbly pavement may form on the soil surface. Substrates are rarely calcareous with a caliche hardpan because caliche tends to restrict rooting of the shallow-rooted <i>Ambrosia dumosa</i>. This vegetation is very common and dominates much of the desert landscape in the southwestern U.S.
Accession Code:
urn:lsid:vegbank.org:commConcept:38564-{97B5E938-D063-4B2F-A7B8-BC085801515F}
Plot-observations of this Community Concept:
0
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