Sahara Desert
The Sahara “The Great Desert” is the world’s largest and hottest desert and third largest desert, after Antarctica and the Arctic. At over 9,400,000 square kilometres, it covers most of North Africa, making it almost as large as China or the United States.
The Sahara covers large parts of Algeria, Chad, Egypt, Libya, Mali, Mauritania, Morocco, Niger, Western Sahara, Sudan and Tunisia.
The Sahara’s boundaries are the Atlantic Ocean on the west, the Atlas Mountains and the Mediterranean on the north, the Red Sea on the east, and the Sudan (region) and the valley of the Niger River on the south.
The Sahara is divided into western Sahara, the central Ahaggar Mountains, the Tibesti Mountains, the Aïr Mountains (a region of desert mountains and high plateaus), Ténéré desert and the Libyan Desert (the most arid region).
The southern border of the Sahara is marked by a band of semiarid savanna called the Sahel; south of the Sahel lies Southern Sudan and the Congo River Basin.
Most of the Sahara consists of rocky hamada; ergs (large areas covered with sand dunes) form only a minor part.
Cities located in Sahara Desert
Important cities located in the Sahara include Nouakchott, the capital of Mauritania; Tamanrasset, Ouargla, Béchar, Hassi Messaoud, Ghardaïa, and El Oued in Algeria; Timbuktu in Mali; Agadez in Niger; Ghat in Libya; and Faya-Largeau in Chad.
Attractions of Sahara Desert
The desert landforms of the Sahara are sand dunes and dune fields or sand seas (erg), stone plateaus (hamada), gravel plains (reg), dry valleys, and salt flats, mountain ranges including the Aïr Mountains, Ahaggar Mountains, Saharan Atlas, Tibesti Mountains, Adrar des Iforas, and the Red Sea hills and the Nile River.
Vegetation
The central part of the Sahara is hyper-arid, with little vegetation. The northern and southern reaches of the desert, along with the highlands, have areas of sparse grassland and desert shrub, with trees and taller shrubs in wadis where moisture collects.
To the north, the Sahara reaches to the Mediterranean Sea in Egypt and portions of Libya, but in Cyrenaica and the Maghreb, the Sahara borders Mediterranean forest, woodland, and scrub ecoregions of northern Africa, which have a Mediterranean climate characterized by a winter rainy season..
To the south, the Sahara is bounded by the Sahel, a belt of dry tropical savanna with a summer rainy season that extends across Africa from east to west.
Ecoregions
The Sahara comprises several distinct ecoregions, and with their variations in temperature, rainfall, elevation, and soil, they harbor distinct communities of plants and animals.
The Atlantic coastal desert occupies a narrow strip along the Atlantic coast, where fog generated offshore by the cool Canary Current provides sufficient moisture to sustain a variety of lichens, succulents, and shrubs.
The North Saharan steppe and woodlands lies along the northern desert, next to the Mediterranean forests, woodlands, and scrub ecoregions of the northern Maghreb and Cyrenaica. Winter rains sustain shrublands and dry woodlands that form a transition between the Mediterranean climate regions to the north and the hyper-arid Sahara proper to the south. It covers 1,675,300 square kilometers in Algeria, Egypt, Libya, Mauritania, Morocco, Tunisia, and Western Sahara.
The Sahara desert ecoregion covers the hyper-arid central portion of the Sahara where rainfall is minimal and sporadic. Vegetation is rare, and this ecoregion consists mostly of sand dunes (erg, chech, raoui), stone plateaus (hamadas), gravel plains (reg), dry valleys (wadis), and salt flats.
The South Saharan steppe and woodlands ecoregion occupies a narrow band running east and west between the hyper-arid Sahara and the Sahel savannas to the south.
In the West Saharan montane xeric woodlands, several volcanic highlands provide a cooler, moister environment that supports Saharo-Mediterranean woodlands and shrublands. The ecoregion covers 258,100 km2 mostly in the Tassili n’Ajjer of Algeria, with smaller enclaves in the Aïr of Niger, the Dhar Adrar of Mauritania, and the Adrar des Iforas of Mali and Algeria.
The Tibesti-Jebel Uweinat montane xeric woodlands ecoregion consists of the Tibesti and Jebel Uweinat highlands. Higher and more regular rainfall and cooler temperatures support woodlands and shrublands of palms, acacias, myrtle, oleander, tamarix, and several rare and endemic plants. The ecoregion covers 82,200 km2 in the Tibesti of Chad and Libya, and Jebel Uweinat on the border of Egypt, Libya, and Sudan.
The Saharan halophytics is an area of seasonally flooded saline depressions which is home to halophytic, or salt-adapted, plant communities. The Saharan halophytics cover 54,000, including the Qattara and Siwa depressions in northern Egypt, the Tunisian salt lakes of central Tunisia, Chott Melghir in Algeria, and smaller areas of Algeria, Mauritania, and Western Sahara.
The Tanezrouft is one of the harshest regions on Earth and the driest in the Sahara, with no vegetation and very little life. It is situated along the borders of Algeria, Niger and Mali, west of the Hoggar mountains.
Flora and fauna
Dromedary camels and goats are the domesticated animals most commonly found in the Sahara.
Several species of fox live in the Sahara, including the fennec fox, pale fox and Rüppell’s fox. The addax, a large white antelope, can go nearly a year in the desert without drinking. The dorcas gazelle is a north African gazelle that can also go for a long time without water.
The Saharan cheetah (Northwest African Cheetah) lives in Algeria, Togo, Niger, Mali, Benin, and Burkina Faso.
Other animals include the monitor lizards, hyrax, Sand vipers, and small populations of African Wild Dog, in perhaps only 14 countries and ostrich. There are also birds such as African Silverbill and Black-throated Firefinch among others. There are also small desert crocodiles in Mauritania and the Ennedi Plateau of Chad.
The central Sahara is estimated to include five hundred species of plants, which is extremely low considering the huge extent of the area.
For more reading
http://www.africanseer.com/african-articles/list-of-deserts-in-africa/index.1.html