Mojave-Sonoran desert dunes
USDA Ecological Section Map
- Primary Life FormHerb
- Elevation10-1300 m
- State RarityS3.2
- Global RarityG4
- DistributionUSA: CA. Mexico (NatureServe)
- Endemic to CaliforniaNo
- Endemic to California Floristic Province and DesertsNo
- Date Added2017/02/10
- Scattered plants with a combined absolute cover of usually > 2% and < 10% in the herbaceous layer; Achnatherum hymenoides, Ambrosia dumosa, Larrea tridentata, Pleuraphis rigida < 2% absolute cover (cf. Thomas et al. 2004).
- Swallenia alexandrae characteristically present in the herbaceous layer (Thomas et al. 2004, Evens et al. 2014).
- Panicum urvilleanum > 2% absolute cover (Thomas et al. 2004).
- Plants sparse to abundant, depending on annual rainfall, and characterized by grasses, such as Panicum urvilleanum or Swallenia alexandrae, or annual and perennial forbs such as Dicoria canescens, Abronia villosa, Croton californicus, Oenothera deltoides, or others (Evens et al. 2014).
- Petalonyx thurberi > 50% relative cover in an open shrub canopy (Evens et al. 2014).
- Wislizenia refracta > 50% relative cover in the herbaceous layer (Evens and Hartman 2007, VegCAMP and AIS 2013).
Other Habitat, Alliance and Community Groupings
|MCV (1995)||Desert sand-verbena series|
|NVCS (2009)||Abronia villosa sparsely vegetated alliance|
|Holland||Active desert dunes, Stabilized and partially stabilized dunes, Stabilized and partially stabilized desert sand fields|
|Munz||Creosote bush scrub|
|CDFW CA Code||22.105.00|
National Vegetation Classification Hierarchy
|Formation Class||Lithomorphic Vegetation (Nonvascular and Sparse Vascular Rock Vegetation)|
|Formation Subclass||Semi-Desert Nonvascular and Sparse Vascular Vegetation|
|Formation||Warm Semi-Desert Cliff, Scree, and Rock Vegetation|
|Division||North American Warm Semi-Desert Cliff, Scree, and Rock Vegetation|
|Macro Group||North American Warm Semi-Desert Cliff, Scree, and Other Rock Vegetation|
|Group||North American warm desert dunes and sand flats|
This dune alliance primarily contains broad-leaved herbs and sparse perennial grasses. Dicoria canescens is most characteristic and present in summer and fall; this herb attained highest frequency across nine different dune systems (Pavlik 1980). D. canescens has many branching stems with gray or white hairs across the plant that deflect sunlight. Plants can grow to 1 m in height, and can flower year-round with good rainfall. Other summer ephemerals include Boerhavia spp. and Allionia incarnata. Astragalus lentiginosus, Abronia villosa, Oenothera deltoides, and many others occur as early spring species.
Other alliances found on these dunes include the Achnatherum hymenoides, Larrea tridentata - Ambrosia dumosa, Pleuraphis jamesii, and Pleuraphis rigida alliances, which are usually closer to the edges of dune systems and experience less shifting sand (Thomas et al. 2004). Previously defined as separate alliances by Thomas et al. (2004), dunes with sparse grass cover, including the special stands of Swallenia alexandrae and those of Panicum urvilleanum, are now combined in this alliance (Evens et al. 2014, NatureServe 2015).
Panicum urvilleanum is a grass with wiry culms to 1 m in height, occurring as tufts or solitary sprigs along long, creeping rhizomes. Although perennial, cover varies annually based on seasonal precipitation. Flowers are in rather long and narrow panicles with hairy spikelets. The species occurs in the Mojave and Sonoran deserts of California and Arizona, and in Argentina and Chile. It forms a sparse cover on open dunes and other deep sand deposits. It usually occurs in the core of the large dune systems on the deepest sand, and may occupy tall, active dunes with relatively steep faces. In those settings, P. urvilleanum can occur as the sole dominant species or co-occur with Dicoria canescens.
Swallenia alexandrae (a CNPS list 1B.2 plant) is a perennial grass that forms hummocks with ascending branches and rhizomes that spread across relatively steep dune slopes. It forms loose panicles of florets that set seed in May to July (USFWS 2007). It was federally listed as endangered in 1978. It has only four occurrences in southern Eureka Valley (CNPS 2007) in Inyo Co. The dunes also support Oenothera californica ssp. eurekensis and Astragalus lentiginosus var. micans, other CNPS list 1B.2 and federally endangered plants. Stands are small, consisting of several grass clumps separated by open and shifting expanses of sand. These stands can ascend to at least half-way up the tallest dunes, and may include the only perennial species found on the upper parts of the dunes. In high-rainfall years, stands can include Dicoria canescens and other annual herbs. Seeds of both Panicum urvilleanum and Swallenia alexandrae are heavy with long hairs that limit gliding and instead ensure surface rolling dispersal on sand (Danin 1996).
Life History Traits of the Principal Species
|Abronia villosa||Dicoria canescens||Panicum urvilleanum||Swallenia alexandrae|
|Life forms||Annual; herb||Annual; herb||Polycarpic perennial; herb; stoloniferous||Polycarpic perennial; herb; stoloniferous|
|Mode of dispersal||Animal? Wind||Wind||Animal; gravity||Animal; gravity|
|Germination agents||Sufficient moisture||Sufficient moisture||Warm, moist conditions||Warm, moist conditions|
|Mode of sprouting||None||None||Rhizomes; tillers||Stolons; tillers|
|Survivability after fire/disturbance||Unknown||No||Fire-hardy||Fire-sensitive|
|Reproductive range||A season||A season||Life of plant||Life of plant|
|Fire return interval||—|
Floras of individual dune systems. Algodones Dunes (Beauchamp 1977), Ballarat Dunes (Pavlik 1985), Borrego Dunes (Beauchamp 1986), Cadiz, Chuckwalla Valley, and Death Valley dunes (DeDecker 1979, 1984), Deep Springs Dunes (Pavlik 1985), Dumont and Eureka dunes (DeDecker 1984), Kelso Dunes (Thorne 1982), Mono Dunes (Pavlik 1985), Olancha Dunes (Pavlik 1985), Panamint Valley, Rice Valley, and Saline Valley dunes (DeDecker 1984), and Saratoga Dunes (Pavlik 1985).
- Colorado Desert (322Ca-b, Cd). This is the most widespread alliance of the Algodones Dunes, the most extensive dune system in California. Other stands exist at Anza-Borrego Desert State Park (Spolsky 1979) and the Coachella Dunes north of the Salton Sea (Schoenherr and Burk 2007).
- Mojave Desert (322Aa-c, Ae-i, Al, An-p). Stands exist at Ballarat, Death Valley, Dumont, Kelso, Olancha, and Panamint Valley dunes in this section (Thomas et al. 2004). Stands of Panicum urvilleanum at Kelso Dunes and Devil’s Playground (Thomas et al. 2004) associate with those of the Pleuraphis rigida alliance.
- Mono (341Df). Stands at Mono Dunes are the northernmost in the state.
- Sonoran Desert (322Ba-d). Stands are most extensive at Cadiz, Chuckwalla Valley, and Rice Valley Dunes with varied plant species composition, though other stands are scattered along sandy areas in the section.
- Southeastern Great Basin (341Fc). Stands of this alliance occur at Deep Springs, Eureka, and Saline Valley where dunes are extensive. Special stands of Swallenia alexandrae and Oenothera californica ssp. eurekensis (CNPS 1B.2 plants) exist only at Eureka Dunes (Bagley 1986, DeDecker 1982). Threats to these stands include invasive plants (including a hybrid of Salsola tragus), variable and/or low precipitation, and visitor usage, which warrant further study (Cipra and Fuhrmann 2012).
- Southern California Mountains and Valleys (M262Bj). Dunes occur near Colton. It is unclear whether this alliance still exists at this location.
- Dicoria canescens , , 
- Oenothera deltoides - Cryptantha spp. 
- Panicum urvilleanum , 
- Petalonyx thurberi , 
- Rumex hymenosepalus 
- Swallenia alexandrae , , 
- Wislizenia refracta , , 
-  Pavlik, B.M. 1980a
-  Thomas, K.;Franklin, J.;Keeler-Wolf, T.;Stine, P. 2004
-  Evens, J.M.;Hartman, S. 2007
-  Evens, J.M.;Sikes, K.;Hastings, D.;Ratchford,J.S. 2014
-  VegCAMP (Vegetation Classification and Mapping Program),;AIS, 2013
-  Evens, J.M.;Klein, A.;Taylor, J.;Hickson, D.;Keeler-Wolf, T. 2006
-  Menke, J.;Hepburn, A.;Johnson, D.;Reyes, E.;Evens, J.;Sikes, K.;Winitsky, S. 2019 (In Progress)
-  Menke, J.;Reyes, E.;Hepburn, A.;Johnson, D.;Reyes, J. 2013
- Cipra, J.;Fuhrmann, K. 2012
- Danin, A. 1996
- Evens, J.M.;Roach-McIntosh, D.;Stout, D. 2012
- Henry, M.A. 1979
- Keeler-Wolf, T. 2007b
- Pavlik, B.M. 1980b
- Pavlik, B.M. 1985
- Pavlik, B.M.;Barbour, M.G. 1988
- Paysen, T.E.;Derby, J.A.;Black, H.;Bleich, V.C.;Mincks, J.W. 1980
- Schoenherr, A.A.;Burk, J.H. 2007
- Slaton, M. 2008
- Thorne, R.F. 1982
- USFWS (United States Fish and Wildlife Service), 2007
- Vasek, F.C.;Barbour, M.G. 1977