ad-Dahna Desert

Category: Desert Biomes.

Geographic Location: Middle East.

Summary: The Ad Dahna Desert comprises the central corridor of the greater Arabian Desert; this hot desert ecosystem has vast expanses of sand and sand dunes, oases ringed with date palms, and dromedary camels.

The Ad Dahna Desert is a bow-shaped corridor of land that comprises the central component of the larger Arabian Desert located within the Arabian Peninsula in southwestern Asia. It is the dominant feature of the central portion of Saudi Arabia. The Ad Dahna Desert is over 620 miles (1,000 kilometers) long and less than 50 miles (80 kilometers) wide. The desert falls under the biome of deserts and xeric shrublands. The Arabian Desert has been prized for centuries due to the presence of valuable mineral resources including petroleum, natural gas, phosphates, and sulfur. Herding, hunting, and other human encroachments have resulted in species extinction and threaten the desert's future environmental health.

Saudi Arabia is the largest country within the Arabian Peninsula, with more than half of its land comprised of desert. The approximately 900,000-square-mile (2.3-million-square-kilometer) Arabian Desert covers the majority of the Arabian Peninsula, mainly within Saudi Arabia. The Ad Dahna Desert serves as the central connection between two other larger components of the Arabian Desert, the northern portion known as the An Nafud (Great Nafud) Desert, and the southeastern portion known as the Rub' al-Khali (Empty Quarter) Desert.

The Ad Dahna Desert has a hot, dry climate and is scientifically characterized as a hot desert. Like all deserts, it is ecologically marked by its aridity, with humidity rates generally averaging between 10 percent to 30 percent. During the day, the land absorbs the heat of the relentless sun, but the desert experiences significant temperature drops in the night as heat loss rapidly accelerates after sunset due to the general lack of cloud cover. Droughts can be years long in duration. Brief periods of rain allow desert plants and animals to survive, but may also create flash floods.

The Ad Dahna Desert contains plateaus of rock, boulders, gravel, and vast stretches of golden yellow sands as well as towering sand dunes. Desert soil is generally coarse and rich in minerals. The sands consist primarily of silicates such as quartz and feldspar. One of the desert's most distinctive features are the horizontal bands of tall sand dunes, also known as veins, which constitute approximately 20 percent of the entire Arabian Desert. The sand dunes are formed and shifted into a variety of changing shapes as the result of the work of water and, most notably, of winds. They are constantly migrating. Iron oxides coating the sand grains sometimes give the dunes red, orange, and purple hues.

Underneath the desert sands lie plains of either gravel or gypsum. Beneath these plains stretches a vast network of underground chambers, passageways, and caves, slowly formed over the centuries by the work of rainwater permeating the rocks. The water carved the rocks and pooled in underground aquifers. Water that remains close to the surface support oases, islands of life in the arid region. Local residents refer to these underground caves as dahls. The process also forms towering stalactites and stalagmites. Although Bedouin nomads have utilized the underground caves for their water resources, a prized commodity for its scarce nature, they were not fully explored or geologically surveyed until the late 20th century.

Flora and Fauna

Although the desert's plant and animal species must adapt to its harsh environment, a surprising diversity of life flourishes in limited numbers. Fossils lend support to scientific theories that the Arabian Peninsula once contained wetlands where desert now dominates. Brief periods of rainfall provide for short growing seasons. Various types of algae, fungi, and lichens grow in the region while Calligonum crinitum, Cyperus conglomeratus, Dipterygium glaucum, Limeum, and Arabicum are common plant species. Among the most common perennials are mimosas, acacias, and aloe. There are few trees; those that are present, such as tamarisks and date palms, grow on the desert's outskirts or oases.

The most symbolic of the Ad Dahna Desert's animals is the dromedary, a one-humped Arabian camel, known for its ability to survive for long periods without water. Other animal species include sand gazelles, white or Arabian oryx, and sand cats. Hyenas, jackals, foxes, civets, hares, golden sand rabbits, ratels, jerboas, mice, rats, porcupines, and hedgehogs can also be present. Among the reptiles, monitors, spiny-tailed lizards, dabbs, geckos, collared lizards, agamids, dammsa, and skinks are common lizards, while horned vipers and cobras are relatively common snakes. Desert oases can support small fish, newts, salamanders, toads, frogs, and turtles.

Both local and migratory birds are present. Native bird species include larks, sand grouse, Arabian coursers, chats, wrens, bustards, owls, falcons, ravens, kestrels, eagles, and vultures. Migratory birds from Europe, Africa, and India pass through on their seasonal journeys between warmer and cooler climates. Eagles can also occasionally be found within the Ad Dahna. Desert insects include flies, mosquitoes, fleas, lice, roaches, ants, termites, beetles, mantids, butterflies, moths, caterpillars, locusts, scorpions, ticks, and spiders.

Environmental Stresses

The Ad Dahna Desert faces numerous environmental threats from human habitation. Historically, Bedouin nomads have been the most well known of the desert's human occupants, successfully adapting to its harsh environment. The Bedouins are primarily herders, raising sheep, goats, donkeys, and horses. They rely heavily on the largely domesticated camel for travel and survival. Overgrazing by livestock herds, primarily camel and goats, has led to significant habitat destruction.

Residents have undertaken efforts to control the region's insects, including the anopheles mosquito, which carries malaria, and the locust, which has caused devastation to crops and vegetation. Hunters' use of motor vehicles in the second half of the 20th century has greatly reduced the presence of targeted mammals such as the gazelle in the region. The striped hyena, jackal, honey badger, and ostrich have become extinct within the desert. Other animals with greatly reduced populations, such as the white oryx and ibex, have slowly begun to recover their numbers in the 21st century.

Centuries of mining and drilling to extract the Arabian Desert's valuable natural resources of oil, natural gas, phosphates, and sulfur have led to pollution and habitat destruction. Instability and conflict in the region encompassing the Ad Dahna Desert have also threatened its ecological health. Most notable were the deliberate and accidental oil spills in nearby Iraq and Kuwait that resulted from the 1991 Gulf War. Desert air, soil, and groundwater all suffered contamination. Ongoing climate change, desertification, and population pressures on the region's scarce water resources endanger both the environment and its human occupants.

There are no large areas of the Ad Dahna or larger Arabian Deserts under legal environmental protection, although that is likely to change in the future. Many environmentalists and scientists feel that the desert ecosystem is at a critical or endangered state due to habitat destruction and species extinction. National governmental hunting regulations, the establishment of wildlife preserves, and the breeding in captivity and reintroduction of endangered animals such as the white oryx and sand gazelle have helped the desert's animal populations to recover. The oryx has been protected since 1961.

Bibliography

Allan, J. A. and Andrew Warren. Deserts: The Encroaching Wilderness: A World Conservation Atlas. New York: Oxford University Press, 1993.

Edgell, H. Stewart. Arabian Deserts: Nature, Origin, and Evolution. New York: Springer, 2006

Jones, Toby Craig. Desert Kingdom: How Oil and Water Forged Modern Saudi Arabia. Cambridge, MA: Harvard University Press, 2010

Oldfield, Sara. Deserts: The Living Drylands. Cambridge, MA: MIT Press, 2004.

Radwan, Omar A. et.al. "Evaluating Properties of Arabian Desert Sands for Use in Solar Thermal Technologies." Solar Energy Materials and Solar Cells, vol. 231, Oct. 2021, doi.org/10.1016/j.solmat.2021.111335. Accessed 14 Jul. 2022.