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Exploring the beautiful nature of California
California Nature: Colorado Desert
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California's Colorado Desert is a part of the larger Sonoran Desert, which extends across southwest North America. The Colorado Desert region encompasses approximately 7 million acres, reaching from the Mexican border in the south to the higher-elevation
Mojave Desert in the north and from the Colorado River in the east to the Laguna Mountains of the Peninsular Ranges in the west. The area includes the heavily irrigated Coachella and Imperial Valleys. The Colorado Desert is home to many unique flora and fauna, many of which can be found no where else on the planet. The majority of the Colorado Desert lies at a relatively low elevation, below 1,000 feet, with the lowest point of the desert floor at 275 feet below sea level at the Salton Sea. Although the highest peaks of the Peninsular Range reach elevations of nearly 10,000 feet, most of the region's mountains do not exceed 3,000 feet. |
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The Colorado Desert's climate distinguishes
it from other deserts. The region experiences greater summer
daytime temperatures than higher-elevation deserts and almost
never experiences frost. In addition, the Colorado Desert
experiences two rainy seasons per year, one in the winter and
again in the late summer, especially toward the southern portion
of the region. The more northerly Mojave Desert has only winter
rains. The west coast Peninsular Ranges, or other west ranges,
of Southern California–northern Baja California, block most
eastern Pacific coastal air and rains, producing an arid
climate. Other short or longer-term weather events can move in
from the Gulf of California to the south, and are often active
in the summer monsoons. These include remnants of Pacific
hurricanes, storms from the southern tropical jet stream, and
the northern Inter-tropical Convergence Zone.
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The Colorado Desert's terrestrial habitats include mixed scrub, including yucca
and cholla cactus; desert saltbush; sandy soil grasslands; and desert dunes. Higher elevations
are dominated by pinyon pine and California juniper, with areas of manzanita and Coulter
pine. In addition to hardy perennials, more than half of the desert’s plant species are herbaceous
annuals, and appropriately timed winter rains produce abundant early spring wildflowers.
In the southern portion of the region, the additional moisture supplied by summer
rainfall fosters the germination of summer annual plants and supports smoketree, ironwood,
and palo verde trees. Common desert wildlife include mule deer, bobcat, desert kangaroo rat,
cactus mouse, black-tailed jackrabbit, Gambel’s quail, and red-diamond rattlesnake. Among
sensitive species are flat-tailed horned lizard, Coachella Valley fringe-toed lizard, desert tortoise,
prairie falcon, Andrews’ dune scarab beetle, Peninsular bighorn sheep, and California
leaf-nosed bat. |
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In the Colorado Desert’s arid environment, aquatic and wetland habitats are limited in
extent but are critically important to wildlife. Groundwater springs and runoff from seasonal
rains form canyon-mouth-associated alluvial fans, desert arroyos, desert fan palm oases,
freshwater marshes, brine lakes, desert washes, ephemeral and perennial streams, and riparian
vegetation communities dominated by cottonwood, willow, and non-native tamarisk. Two
of the region’s most significant aquatic systems are the Salton Sea and the Colorado River.
While most desert wildlife depend on aquatic habitats as water sources, a number of
species, such as arroyo toad, desert pupfish, Yuma clapper rail, and southwestern willow
flycatcher, are restricted to these habitats. In some places, summer rains produce short-lived
seasonal pools that host uncommon species, such as Couch’s spadefoot toad.
Desert fan palm oases are rare ecological communities found only in the Colorado Desert.
They occur only where permanent water sources are available, such as at springs or along
fault lines, where groundwater is forced to the surface by the movement of hard, impermeable
rock
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Public lands in the desert are managed by several different federal and state agencies,
all of which have differing sets of missions that often expand beyond wildlife conservation. Although the Colorado Desert remains one of the least-populous regions in California,
human activities have had substantial impacts on the region’s habitats and wildlife. Many
unique communities, particularly aquatic and dune systems, are limited in distribution and
separated by vast expanses of inhospitable, arid desert terrain. Even limited human disturbances
can have markedly deleterious effects on the endemic and sensitive species supported
by these unique regional systems. The diverse wildlife inhabiting the Colorado Desert include many species specially
adapted to the unique desert habitats. There are 481 vertebrate species that inhabit the
Colorado Desert region at some point in their life cycle, including 282 birds, 82 mammals,
66 reptiles, 16 amphibians, and 35 fish. |
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