Anza-Borrego Desert State
IUCN category III (natural monument or feature)
Desert view from Font's Point
Location	San Diego, Imperial, and Riverside Counties, California, USA
Nearest city	Borrego Springs and Julian, California
Coordinates	33°15′33″N 116°23′57″W / 33.25917°N 116.39917°W / 33.25917; -116.39917Coordinates: 33°15′33″N 116°23′57″W / 33.25917°N 116.39917°W / 33.25917; -116.39917
Area	585,930 acres (237,120 ha)
Established	1933
Governing body	California Department of Parks and Recreation

Anza-Borrego Desert State Park is a state park located within the Colorado Desert of Southern California, United States. The park takes its name from 18th-century Spanish explorer Juan Bautista de Anza and borrego, the Spanish word for bighorn sheep.^[1] With 600,000 acres (2,400 km²) that include one-fifth of San Diego County, Anza-Borrego is the largest state park in California and, after New York's Adirondack Park, the second largest in the continental United States. The park occupies eastern San Diego County and reaches into Imperial and Riverside Counties, enveloping two communities: Borrego Springs (home of the park headquarters) and Shelter Valley.

Geography[link]

Anza-Borrego is around a two-hour drive northeast from San Diego, southeast from Riverside or Irvine, and south from Palm Springs. The Park is an anchor in the Mojave and Colorado Deserts Biosphere Reserve, and adjacent to the Santa Rosa and San Jacinto Mountains National Monument.

Visiting[link]

Vista of the Anza Borrego desert landscape.

Anza-Borrego Desert State Park includes 500 miles (800 km) of dirt roads, twelve designated wilderness area, and 110 miles (180 km) of hiking trails to provide visitors with many opportunities to experience the Park's unique version of the Colorado Desert environs. Park information and maps, interpretive events and displays, and listening devices for the hearing impaired, are all available in the Visitor Center.^[2] Anza-Borrego Desert State Park has wi-fi access in various sections of the park, as do fifty five other California State Parks.

Many visitors approach Anza-Borrego from the east-Coachella Valley side via California County Route S22 and S78. Visitors can also approach from the west-Pacific Ocean side via California County Routes S79 or S67 and add experiences of passing through the high and forested Laguna Mountains, such as in Cuyamaca Rancho State Park.^[3] These highways climb from the coast to elevation 2,400-foot (730 m), then descends 2,000-foot (610 m) down into the Borrego Valley in the center of the park. This great bowl of the Anza-Borrego desert is surrounded by mountains, with the Vallecito Mountains southward and the highest Santa Rosa Mountains to the north. They are in the park's wilderness area, without paved roads and with the only year-round creeks in Anza-Borrego.

Flora and fauna[link]

See also: Category: Flora of the California desert regions
and also: Category: Fauna of the Colorado Desert

Cactus in bloom

Desert Bighorn Sheep at Palm Canyon Oasis.

The habitats of Anza-Borrego Desert State Park are primarily within the Colorado Desert ecosystem of the Sonoran Desert ecoregion. The higher extreme northern and eastern sections in the Peninsular Ranges are in the California montane chaparral and woodlands ecoregion.

The park features: bajadas and desert washes; rock formations and colorful badlands, vast arid landscapes and dramatic mountains. The bajadas are predominantly creosote bush-bur sage with Creosote bush (Larrea tridentata) and the palo verde-cactus shrub ecosystems with the Palo Verde tree (Parkinsonia microphylla), cacti, and Ocotillo. In the washes, Colorado/Sonoran microphylla woodlands can be found. These woodlands include such plants as Smoke Tree (Psorothamnus spinosus), Honey Mesquite (Prosopis velutina), and Catclaw (Acacia greggii).^[4]

Anza Borrego has natural springs and oases with the state's only native palm, the endangered California fan palm (Washingtonia filifera). Seasonal wildflower displays can be stunning in any plant community association in throughout the Park. The high-county to the north and east has Closed-cone pine forests, Manzanitas, and Oak woodlands.

The oases are prolific with wildlife of all types of fauna, especially for bird-watching. Throughout the park visitors may see Kit foxes, Mule deer, Coyotes, Greater roadrunners, Golden eagles, Black-tailed jackrabbits, Ground squirrels, Kangaroo rats, Quail, and Prairie falcons. In the reptile class Desert iguanas, Chuckwallas and the Red diamond rattlesnake can be seen – with care.

Desert Bighorn Sheep[link]

Some areas of Anza-Borrego Park are habitat for the Peninsular bighorn sheep, often called Desert Bighorn Sheep. Few park visitors see them, and the sheep are justly wary. A patient few observers each year see and count this endangered species to study the population, and to monitor its current decline from human overpopulation encroachment.^{[5][citation needed]}

Geology and paleontology[link]

Panoramic view from Font's Point westward over Borrego Valley to the Laguna Mountains.

The expanses of Anza-Borrego's eroded badlands also provide a different view into the region's long vanished tropical past. The inland of southeastern California was not always a desert. Paleontology, the study of the fossilized remains of ancient life, is the key to understanding and engaging this prehistoric world. Anza-Borrego has an exceptional fossil record; and include preserved plants, a variety of invertebrate shells, animal tracks, and an array of bones and teeth. Most Anza-Borrego fossils date from six million to under a half million years in age, or about 60 million years after the last dinosaur age ended.^[6]

Geology[link]

Anza-Borrego rock outcrop and flora

Anza-Borrego Desert lies in a unique geologic setting along the western margin of the Salton Trough. This major topographic depression with the Salton Sink having elevations of 200-foot (61 m) below sea level, forms the northernmost end of an active rift valley and a geological continental plate boundary. The Trough extends north from the Sea of Cortez (Gulf of California) to San Gorgonio Pass, and from the eastern rim of the Peninsular Ranges eastward to the San Andreas Fault Zone along the far side of the Coachella Valley. Over the past 7 million years a relatively complete geologic record of over 20,000-foot (6,100 m) of fossil bearing sediment has been deposited within the Park along the rift valley's western margin. Paleontological remains are widespread and diverse, and are found scattered over hundreds of square miles of eroded badlands terrain extending south from the Santa Rosa Mountains Range into northern Baja California in Mexico.

Both marine and terrestrial environments are represented by this long and rich fossil record. Six million years ago the ancestral Gulf of California filled the Salton Trough, extending northward past what would become the city of Palm Springs. These tropical waters supported a profusion of both large and small marine organisms. Through time, the sea gave way as an immense volume of sediment eroded during the formation of the Grand Canyon spilled into the Salton Trough. Little by little, the ancestral Colorado River built a massive river delta across the sea way. Fossil hard woods from the deltaic sands and associated coastal plain deposits suggest that the region received three times as much rainfall as present times.

The Anza-Borrego region gradually changed from a predominately marine environment in to a system of interrelated terrestrial habitats. North of the Colorado River Delta and intermittently fed by the River, a sequence of lakes and playa lakes has persisted for over 3 million years. At the same time, sediments eroded from the growing Santa Rosa Mountains and other Peninsular Ranges to spread east into the Trough. It is these sediments that provide an almost unbroken terrestrial fossil record, ending only a half million years ago. Here, the deposits of ancient streams and rivers trapped the remains of wildlife that inhabited a vast brushland savannah laced with riparian woodlands.

Fossils[link]

This record of changing environments and habitats includes over 550 types of fossil plants and animals, ranging from preserved microscopic plant pollen and algae spores to baleen whale bones and mammoth skeletons. Many of the species are extinct and some are known only from fossil remains recovered from this Park. Combined with a long and complete sedimentary depositional sequence, these diverse fossil assemblages are an unparalleled paleontologic resource of international importance. Both the Pliocene-Pleistocene Epoch boundary and the Blancan-Irvingtonian North American Land Mammal Ages boundary fall within the long geological record from the Anza-Borrego Desert. Environmental changes associated with these geological time divisions are probably better tracked by fossils from Anza-Borrego than in any other North American continental platform strata. These changes herald the beginning of the Ice Ages, and the strata contain fossil clues to the origin and development of modern southwestern desert landscapes.

The first fossils, marine shells from the ancient Sea of Cortez and fresh water shells from a prehistoric era Lake Cahuilla, precursor of present day Salton Sea, were collected and described by William Blake in 1853. Blake was the geologist and mineralogist for the Pacific Railroad Surveys commissioned by Congress and President Franklin Pierce to find a railway route to the Pacific. It was Blake who first named this region the Colorado Desert.

Marine period[link]

Pre-Columbian rock art in the Indian Hill archeological area.

Since the late 19th century, numerous scientific studies and published papers have centered on the marine organisms that inhabited the ancient Sea of Cortez. Fossil assemblages from the classic 'Imperial Formation' include calcareous nanoplankton and dinoflagellates, foraminifera, corals, polychaetes, clams, gastropods, sea urchins, and sand dollars, and crabs and shrimp. The deposits also yield the remains of marine vertebrates such as sharks and rays, bony fish, baleen whale, walrus, and dugong.

Marine environments such as outer and inner shelf, platform reef, and near shore beach and lagoon are all represented within the 'Imperial Formation.' As the sea shallowed, estuarine and brackish marine conditions prevailed, typified by thick channel deposits of oyster and pecten shell coquina that now form the "Elephant Knees" along Fish Creek. Many of the marine fossils are closely related to forms from the Caribbean Sea. They document a time before the isthmus of Panama formed, when the warm Gulf Stream of the western Atlantic invaded eastern Pacific Ocean waters.

Terrestrial period[link]

As North and South America connected about 3 million years ago, terrestrial faunal north-south migrations began on a continental scale called the Great American Biotic Interchange, and are present in Anza-Borrego's fossils. Animals like giant ground sloths and porcupines made their first appearance in North America at this time.

The oldest terrestrial vertebrate fossils from the Colorado Desert predate the late Miocene invasion of the Sea of Cortez. These very rare fossils, which include a gomphothere (elephant-like mammal), rodent, felid and small camelid, and were collected from 10–12 million year old riverine and near shore lake deposits. However, the most significant and abundant vertebrate fossils have been recovered from the latest Miocene through late-Pleistocene riverine and flood plane deposits of the Palm Spring Formation in the Vallecito and Fish Creek Badlands and Ocotillo Conglomerate exposed in the Borrego Badlands. These fossil assemblages occur in a 3.5 million year long uninterrupted stratigraphic sequence that has been dated using horizons of volcanic ash and paleomagnetic methods.

The bestiary for this savannah landscape reads like a "who's-who" for some of the most unique creatures to inhabit North America - animals such as:
Geochelone, a giant bathtub-sized tortoise; Aiolornis incredibilis, the largest flying bird of the northern hemisphere, with 17-foot (5.2 m) wing span; Paramylodon, Megalonyx and Nothrotheriops, giant ground sloths, some with bony armor within their skin; Pewelagus, a very small rabbit (paleontologists can name with a sense of humor); Borophagus, a hyena-like dog; Acrtodus, a giant short-faced bear; Smilodon, a saber-toothed cat; Miracinonyx, the North American cheetah; Mammuthus imperator, the largest known mammoth; Tapirus, an extinct tapir; Equus enormis and Equus scotti, two species of extinct Pleistocene horse; Gigantocamelus a giant camel; and Capromeryx, the dwarf pronghorn.

Morteros, bedrock mortar grinding holes, in the Indian Hill area.

Native Americans[link]

The Native Americans of the Anza-Borrego mountains and deserts included the Cahuilla, Cupeño, Diegueño, and Kumeyaay Indian tribes. It was the homeland of these peoples for thousands of years, and their artists created petroglyph and pictogram rock art expressing their cultures.^[7]

Park interpretive associations[link]

The Anza-Borrego Foundation (ABF), founded in 1967, is a non-profit educational organization and is the sole cooperating association of Anza-Borrego Desert State Park. It manages all sales at the State Park Visitor Center and State Park Store. The Anza-Borrego Institute, the education arm of ABF, provides in-depth educational courses to more than 1,300 visitors each year. The institute offers in-depth field programs, a fifth grade environmental camp, citizen science research, and Parks Online Resources for Teachers and Students. ABF's mission is to protect and preserve the natural landscapes, wildlife habitat, and cultural heritage of Anza-Borrego Desert State Park for the benefit and enjoyment of present and future generations.^[8]

The Anza-Borrego Desert Natural History Association operates the Borrego Desert Nature Center in Borrego Springs. The nature center offers educational, environmental, and recreational programs for all ages including desert tours, guided hikes, and lectures.^[9]

Gallery[link]

• Flora and Fauna of Anza-Borrego Desert Park
• 

  Peninsular Bighorn Sheep in Anza-Borrego.

• 

  An Ocotillo plant common in Anza-Borrego.

• 

  A Desert Marigold pushes its way through the dry, cracked, and sun-hardened desert after a rare and substantial rainfall.

• 

  Common Chuckwalla, Sauromalus ater in Palm Canyon, near Palm Springs.

See also[link]

• Ocotillo Wells, California
• Santa Rosa and San Jacinto Mountains National Monument
• Shelter Valley, California
• Mud Caves
• Mojave and Colorado Deserts Biosphere Reserve
  • Man and the Biosphere Programme
  • World Network of Biosphere Reserves in the United States

References[link]

• C. Michael Hogan. 2009. California Fan Palm: Washingtonia filifera, GlobalTwitcher.com, ed. Nicklas Stromberg
• George T. Jefferson and Lowell Lindsay. 2006. Fossil Treasures of the Anza-Borrego Desert (Sunbelt Publications, San Diego). ISBN 0-932653-50-2

Further reading[link]

• Robin Halford. 2005. Hiking in Anza-Borrego Desert: Over 100 Half-Day Hikes (Anza Borrego Desert Natural History Association, Borrego Springs). ISBN 0-910805-13-X
• Diana Lindsay, 2001. Anza-Borrego A to Z: People, Places, and Things (Sunbelt Publications, San Diego). ISBN 0-932653-42-1
• Lowell Lindsay and Lindsay, Diana. 2006. The Anza-Borrego Desert Region: A Guide to the State Park and Adjacent Areas of the Western Colorado Desert. Fifth Edition (Wilderness Press, Berkeley). ISBN 0-89997-400-7
• George T. Jefferson and Lowell Lindsay. 2006. Fossil Treasures of the Anza-Borrego Desert (Sunbelt Publications, San Diego). ISBN 0-932653-50-2
• Serenity (film) – location shooting in the park for the 2005 feature film shows the environs.
• Wild, Peter (2005). Marshal South, of Yaquitepec. Johannesburg, California: The Shady Myrick Research Project. pp. 157. OCLC 58796769.  – Marshal South and his wife, Tanya, wrote a series of highly popular "Desert Refuge" articles (1940–1946) for the Desert Magazine about their primitive life in the desert. They lived in a home they called Yaquitepec on a mountaintop named Ghost Mountain near Blair Dry Lake

External links[link]

Wikimedia Commons has media related to: Anza-Borrego Desert State Park

• Anza-Borrego Desert State Park
• Anza-Borrego Foundation
• Anza-Borrego Desert Natural History Association
• Juan Bautista de Anza National Historic Trail
• Anza Borrego Tribute