rain shadow desert. That is because two massive mountain ranges, the Sierra Madre Occidental on the west and the Sierra Madre Oriental on the east, border the Mexican portion of the Chihuahuan. These mountains block most of the moisture from the Gulf of Mexico and the Pacific Ocean from reaching the land
river valleys and the changes in elevation produce a variety of habitats
Big Bend in Texas where the elevation is low, there are many lizards which could not survive the cool winters of the desert mountains. And although fish are usually not thought of as desert dwellers, there are many in the Chihuahuan's aquatic habitats.
summer rains, occurring in June and July, are called monsoons, and are caused by moist air that penetrates from the Gulf of Mexico.
Mesilla Valley where the Rio Grande runs, there are large amounts of water in an aquifer that is only 15-20 feet under the surface. However, mountainous areas of the desert, or valleys that do not contain rivers often have their water as far down as 200-700 feet below the surface
sub-surface water ... oases ... most famous is cuato cienegas
In the 1850s, the grass in the northern Chihuahuan Desert was said to grow as high as the belly of a horse
There are deserts in Antarctica and on the icecaps of Greenland which are never hot. The Atacama Desert in Chile, one of the most arid places on earth, borders on the ocean. It is true that some deserts like the Sahara in Africa have sand dunes, but that's not what makes them deserts. In fact, only about 1/4 of all desert surfaces are made of sand - the rest are dirt, clay, rock, ice or some other mixture of organic and inorganic materials. And although deserts generally have little precipitation, many have at least one rainy season each year. In fact, the Chihuahuan Desert in New Mexico has two different annual rainy periods: a monsoon season in summer and mild rains in early winter.
lowland Sonoran Desert of Mexico and Arizona contains saguaro (sa HUA ro) cacti which provide homes for many cactus-nesting birds. Others deserts at higher altitudes, such as the Chihuahuan Desert, may be home to fewer cacti, but contain many shrubs like mesquite or creosote bushes with their own animal residents. Some deserts may be carpeted in green during rainy seasons, providing food for grazing animals. Or they may be flat expanses of tall grasses supporting large populations of kangaroo rats and other burrowing rodents. One thing is certain - no desert is completely empty of plant and animal life.
most common scientific method for classifying climates (the Köppen system) a desert is a place where more water would be lost through evaporation than is gained from precipitation
North American West, there are four separate deserts that border on each other: the Chihuahuan, the Sonoran, the Mojave, and the Great Plains
although the Sonoran and Chihuahuan deserts are in the same latitude, the Sonoran is hotter than the Chihuahuan because it is at a lower altitude. And the Great Basin, which extends all the way to the northern border of Idaho, is the coldest of all. This is partly due to its northern latitude, partly to the fact that it has the highest altitude of any North American desert, and partly to the fact that the wind currents blowing over the region during the winter carry bursts of Arctic air.
Our current North American deserts are mere youngsters - only about 8000 - 10,000 years old. Glaciers were one important factor in the development of these deserts. During the last ice age, around 50,000 years ago, many of the basins in the North America were filled with water. About 8000 to 10,000 years ago, after the last glaciers retreated, the current deserts were formed with similar climate, size, and many of the same species of plants and animals that we have today.
"rain shadow" desert often forms when there are two mountain ranges, one on the east and one on the west of a land expanse, which block moist ocean air from reaching the land.
Gobi in China (blocked by the Himalayas), and the eastern and central deserts in Australia.
Early hunting and gathering societies, part of the Jornada Mogollon culture, first roamed this area. Later, various Apache tribes made these lands their home
established by the Spanish between Chihuahua, Mexico and Santa Fe
1887, the first Homestead was filed with the U.S. government
Jornada 1927, Congress granted public lands to the College for research purposes. The last parcel was acquired in 1984 through a "land swap" between the federal government and the State of New Mexico.
Soils range from sandy loams to clays overlying caliche hardpan.
Creosote bush dominates the upper slopes of the mountains and the hills along the river. At lower elevations, the creosote bush type grades into the mesquite type that grows on sandier soils, and into the tarbush type on heavier soils. The plains area, once dominated by black grama, today has been invaded by mesquite. These mesquite stands are interspersed with snakeweed and many species of grasses and forbs.
Among the larger mammals are mule deer, pronghorn antelope, gemsbok, bobcat, coyote, badger, and fox. Mountain lions have been sighted. There are also many rabbit and rodent species. Several bird species migrate throughout the area, but a large number also live and nest on the rangeland. Species such as roadrunners, hawks, and occasionally golden eagles are seen on the Center. Numerous lizard and snake species also inhabit these lands.
Early travelers on the Journada del Muerto such as Susan Shelby Magoffin of El Paso reported in her diary that the area was predominately grama grass. Interpretations from an 1858 land survey indicate much larger areas of grassland than today. Shrubs were restricted to gravelly upland, arroyos and river sites.
Early researchers at the CDRRC such as Ken Valentine and John Norris saw an increase in the number of undesirable shrubs and the reduction in the size of grassland... The decision was made to begin a brush control program that would try to preserve the desert grassland for future researchers. Today that program continues to control shrub invasion which threatens to eliminate much of the grassland.
Chihuahuan Desert Rangeland Research Center (CDRRC) has experienced sweeping changes in type and density of vegetation.
1858 a land survey of the northern 1/2 of the lands of the Center was completed along with the lands of the neighboring current USDA Jornada Experimental Range. A subsequent land survey in 1881 covering the mountainous lands on the southern part of the center and along the Rio Grande on the west finished the first land survey for the Center.
vegetation surveys made in 1935 and 1938
Each vegetation type was defined by plant dominance and animal unit months (livestock carrying capacity) were calculated using the forage-acre-factor technique.
1998 survey was done by using aerial photos and ground-truthing to verify vegetation types. The smallest areas delineated were 10 acres.
No estimates of livestock carrying capacity were estimated for the surveys made in the 1800's and 1998.