Algodones Dunes

This area includes both the sand dunes and the alluvial flats to the east and west. These dunes, 1.6 to 5 km (1 to 3 miles) wide, are the largest in the State and are of considerable biological and geological interest.

One of the major concentrations of arenicolous animals in the State is found here. The reptile fauna is among the most interesting on the continent. Some 26 species have been found in the area including the sidewinder, Crotalus cerastes, Western diamondback rattlesnake, Crotalus atrox, spotted night snake, Hypsiglena torquata, Western ground snake, Sonora semiannulata, long-nosed snake, Rhinocheilus lecontei, Colorado Desert fringe-toed lizard, Uma notata, flat-tailed and desert horned lizard, Phrynosoma m'calli and Phrynosoma platyrhinos, zebra-tailed lizard, Callisaurus draconoides, and the desert crested lizard, Dipsosaurus dorsalis.

Among the 23 species of mammals observed here are the round-tailed ground squirrel, Citellus tereticaudus, kit fox, Vulpes macrotis, and numerous rats and mice. LeConte's thrasher, Toxostoma lecontei, and the roadrunner, Geococcyx californianus, are resident, but some 40 birds are observed on migration. The red-spotted toad, Bufo punctatus, and Couch's spadefoot, Scaphiopus couchi, are found here. Entomologically, it is a very rich area though still relatively uncollected. A preliminary review reveals that 44 species may be endemic here. A fairy shrimp, Thamnocephalus platyurus, is found here also.

Plants growing on the dunes include Spanish needles, Palafoxia linearis var. gigantea, desert croton, Croton wigginsii, silver-leaved sunflower, Helianthus tephrodes, sand sponge, Pholisma sonorae, and the rare desert buckwheat, Eriogonum deserticola. Along the eastern edge of the dunes there are fairly dense stands of palo verde, Cercidium floridum, and ironwood, Olneya tesota, and further east there is a fine stand of the latter species. West, between the canals, is a unique stand of creosote bush, Larrea tridentata, which never exhibit "permanent wilt," presumably as the result of an underground flow of water.

Relicts of Lake Cahuila, the dunes are excellent examples of fossil lake-shoreline dunes and provide an unusual array of dune forms. They show the aging processes well, slow mineralogical alteration, the growth of vegetation, and gradual form alteration. They are also important in the interpretation of the paleoclimatological history of the region.

Mean annual rainfall is approximately 6.5 cm. (2" inches) annually and the area is one of the driest in the United States.

Integrity: The area lies within the Imperial Sand Hills Recreation Lands managed by the Bureau of Land Management. A proposal is pending to designate the area a Research Natural Area but to date no action has been taken. Dune buggies are threatening much of the biological values.

Use: Research, educational. For information contact Bureau of Land Management.

Ref: Anon., 1972. Establishment Proposal; Algodones Dunes Research Natural Area, Imperial County, California. No pub. Bibliography.

January 1975