Arabian Desert

The Arabian Desert () is a vast desert wilderness in Western Asia that occupies almost the entire Arabian Peninsula. It stretches from Yemen to the Persian Gulf and Oman to Jordan and Iraq. It occupies most of the Arabian Peninsula, with an area of . It is the fifth largest desert in the world, and the largest in Asia. At its center is "Ar-Rub' al-Khali" (The Empty Quarter), one of the largest continuous bodies of sand in the world. It is an extension of the Sahara Desert.
Gazelles, oryx, sand cats, and spiny-tailed lizards are just some of the desert-adapted species that survive in this extreme environment, which features everything from red dunes to deadly quicksand. The climate is mostly dry (the major part receives around of rain per year but some very rare places receive as little as 50 mm), and temperatures oscillate between very high heat and seasonal night time freezes. It is part of the deserts and xeric shrublands biome and lie in biogeographical realms of the Palearctic (northern part) and Afrotropical (southern part).
The Arabian Desert ecoregion has little biodiversity, although a few endemic plants grow here. Many species, such as the striped hyena, jackal and honey badger have died out as a result of hunting, habitat destruction, overgrazing by livestock, off-road driving, and human encroachment on their habitat. Other species, such as the Arabian sand gazelle, have been successfully re-introduced and are protected at a number of reserves.
Geography.
The desert lies mostly in Saudi Arabia, and covers most of the country. It extends into neighboring portions of southern Iraq, southern Jordan, central Qatar, most of the Abu Dhabi emirate in the United Arab Emirates (UAE), western Oman, and northeastern Yemen. The ecoregion also includes most of the Sinai Peninsula in Egypt and the adjacent Negev desert in southern Israel.
Climate.
The Arabian Desert has a subtropical, hot desert climate, similar to the climate of the Sahara Desert (the world's largest hot desert). The Arabian Desert is actually an extension of the Sahara Desert over the Arabian peninsula. 
The climate is mainly dry. Most areas get around of rain per year. Unlike the Sahara Desert—more than half of which is (having rainfall of less than per year)—the Arabian Desert has only a few hyperarid areas. These rare driest areas may get only 30 to of rain per year. 
The Arabian Desert’s sunshine duration index is very high by global standards: between 2,900 hours (66.2% of daylight hours) and 3,600 hours (82.1% of daylight hours), but typically around 3,400 hours (77.6% of daylight hours). Thus clear-sky conditions with plenty of sunshine prevail over the region throughout the year and cloudy periods are infrequent. 
Visibility at ground level is relatively low, despite the brightness of the sun and moon, because of dust and humidity. 
Temperatures remain high all year round. In the summer, in low-lying areas, average high temperatures are generally over . In extremely low-lying areas, especially along the Persian Gulf (near sea level), summer temperatures can reach . Average low temperatures in summer are typically over and in the south can sometimes exceed . Record high temperatures above have been reached in many areas of the desert, partly because its overall elevation is relatively low. 
Flora.
The Arabian Desert ecoregion has about 900 species of plants.
The Rub'al-Khali has very limited floristic diversity. There are only 37 plant species, 20 recorded in the main body of the sands and 17 around the outer margins. Of these 37 species, one or two are endemic. Vegetation is very diffuse but fairly evenly distributed, with some interruptions of near sterile dunes. Some typical plants are "Calligonum crinitum" on dune slopes, "Cornulaca arabica" (saltbush), "Salsola stocksii" (saltbush), and "Cyperus conglomeratus". Other widespread species are "Dipterygium glaucum, Limeum arabicum", and "Zygophyllum mandavillei".
Very few trees are found except at the outer margin (typically "Acacia ehrenbergiana" and "Prosopis cineraria"). Other species are a woody perennial "Calligonum comosum", and annual herbs such as "Danthonia forskallii".
Fauna.
The Arabian Desert has 102 native species of mammals. Native mammals include the Arabian oryx ("Oryx leucoryx"), sand gazelle ("Gazella marica"), mountain gazelle ("G. gazella"), Nubian ibex ("Capra nubiana"), Arabian wolf ("Canis lupus arabs"), striped hyaena ("Hyaena hyaena"), caracal ("Caracal caracal"), sand cat ("Felis margarita"), red fox ("Vulpes vulpes"), and Cape hare ("Lepus capensis").
The Asiatic cheetah and Asiatic lion used to live in the Arabian Desert.
The ecoregion is home to 310 bird species.
People, language and cultures.
The area is home to several different cultures, languages, and peoples, with Islam as the predominant faith. The major ethnic group in the region is the Arabs, whose primary language is Arabic.
Settlements.
In the center of the desert lies Riyadh, the capital of Saudi Arabia, with more than 7 million inhabitants. Other large cities, such as Dubai, Abu Dhabi, or Kuwait City, lie on the coast of the Persian Gulf.
Natural resources.
Natural resources available in the Arabian Desert include oil, natural gas, phosphates, and sulfur.
Conservation and threats.
Threats to the ecoregion include overgrazing by livestock and feral camels and goats, wildlife poaching, and damage to vegetation by off-road driving.
The conservation status of the desert is critical/endangered. In the UAE, the sand gazelle and Arabian oryx are threatened, and honey badgers, jackals, and striped hyaenas already extirpated.
Protected areas.
4.37% of the ecoregion is in protected areas.
Saudi Arabia has established a system of reserves overseen by the National Commission for Wildlife Conservation and Development (NCWCD).
Protected areas in the United Arab Emirates include Al Houbara Protected Area (2492.0 km2), Al Ghadha Protected Area (1087.51 km2), Arabian Oryx Protected Area (5974.47 km2), Ramlah Protected Area (544.44 km2), and Al Beda'a Protected Area (417.0 km2).