Ethiopian Highlands

The Ethiopian Highlands is a rugged mass of mountains in Ethiopia, situated in the Horn region in northeast Africa. It forms the largest continuous area of its elevation in the continent, with little of its surface falling below 1,500 m (4,900 ft), while the summits reach heights of up to 4,550 m (14,930 ft). It is sometimes called the Roof of Africa due to its height and large area.[1] Most of the Ethiopian Highlands are part of central and northern Ethiopia, and its northernmost portion reaches into Eritrea.

Ethiopian Highlands
Semien Mountains 13
The Semien Mountains with the tallest peak Ras Dashen (4,550 m) in the Ethiopian Highlands are a World Heritage Site and include the Semien Mountains National Park
Highest point
Elevation4,550 m (14,930 ft) at Ras Dashen
Geography
Ethiopia relief location map
Topographic map
LocationEthiopia
Geology
Age of rock75 million years
Mountain typeMountain range

History

Ancient Coffee Cup, Kafa Tribe (13186929813)
A coffee cup from the era of the Kaffa Kingdom

In the southern parts of the Ethiopian Highlands once was located the Kingdom of Kaffa, a medieval early modern state, whence the coffee plant was exported to the Arabian Peninsula. The land of the former kingdom is mountainous with stretches of forest. The land is very fertile, capable of three harvests a year. The term "coffee" derives from the Arabic qahwah ( قهوة)[2] and is traced to Kaffa.[2][3]

Physical geography

The Highlands are divided into northwestern and southeastern portions by the Main Ethiopian Rift, which contains a number of salt lakes. The northwestern portion, which covers the Tigray and Amhara Regions, includes the Semien Mountains, part of which has been designated the Simien Mountains National Park. Its summit, Ras Dashen (4,550 m), is the highest peak in Ethiopia. Lake Tana, the source of the Blue Nile, also lies in the northwestern portion of the Ethiopian Highlands.

The southeastern portion's highest peaks are located in the Bale Zone of Ethiopia's Oromia Region. The Bale Mountains, also designated a national park, are nearly as high as those of Semien. The range includes peaks of over 4,000 m. Among these are Mount Tullu Demtu (4,337 m), which is the second-highest peak in Ethiopia, and Mount Batu (4,307 m).

Most of the country's major cities are located at elevations of around 2,000–2,500 m (6,600–8,200 ft) above sea level, including historic capitals such as Gondar and Axum.

Geology

Dendi Caldera
Dendi Caldera, a collapsed volcano in the mountain region

The Ethiopian Highlands began to rise 75 million years ago, as magma from the Earth's mantle uplifted a broad dome of the ancient rocks of the Arabian-Nubian Shield. The opening of the Great Rift Valley split the dome of the Ethiopian Highlands into three parts; the mountains of the southern Arabian Peninsula are geologically part of the ancient Ethiopian Highlands, separated by the rifting which created the Red Sea and Gulf of Aden and separated Africa from Arabia.

Around 30 million years ago, a flood basalt plateau began to form, piling layers upon layers of voluminous fissure-fed basaltic lava flows. Most of the flows were tholeiitic, save for a thin layer of alkali basalts and minor amounts of felsic (high-silica) volcanic rocks, such as rhyolite. In the waning stages of the flood basalt episode, large explosive caldera-forming eruptions also occurred.

The Ethiopian Highlands were eventually bisected by the Great Rift Valley as the African continental crust pulled apart. This rifting gave rise to large alkaline basalt shield volcanoes beginning about 30–31 million years ago.[4]

The northern Ethiopian Highlands contain four discernible planation surfaces the oldest one being formed not later than in the Ordovician epoch.[5] The youngest surface formed in the Cenozoic being partly covered by the Ethiopia-Yemen Continental Flood Basalts.[5] Contrary to what has been suggested for much Africa planation surfaces in northern Ethiopia do not appear to be pediplains nor etchplains.[5]

Climate

The predominant climate of the Ethiopian Highlands is tropical monsoon, which in general is cooler than in other regions at similar proximity to the equator due to elevation.

Ecology

Ethiopian Highlands 01
Ethiopian Highlands with Ras Dashan in the background

Because the highlands elevate Ethiopia, located close to the equator, this has resulted in giving this country an unexpectedly temperate climate. Further, these mountains catch the precipitation of the monsoon winds of the Indian Ocean, resulting in a rainy season that lasts from June until mid-September.[6] These heavy rains cause the Nile to flood in the summer, a phenomenon that puzzled the ancient Greeks, as the summer is the driest season in the Mediterranean climate that they knew.

The Ethiopian Highlands share a similar flora and fauna of other mountainous regions of Africa; this distinctive flora and fauna is known as Afromontane but from the time of the last ice age has been populated with some Eurasian (palearctic) flora. The habitats are somewhat different on either side of the Great Rift Valley that splits the highlands.

At lower elevations, the highlands are surrounded by tropical savannas and grasslands, including the Sahelian acacia savanna to the northwest, the East Sudanian Savanna to the west, and the Somali Acacia-Commiphora bushlands and thickets to the northeast, east, south, and through the Rift Valley.

The highlands themselves are divided into three distinct ecoregions, distinguished by elevation. The Ethiopian montane forests lie between 1,100 and 1,800 meters' elevation, above the lowland grasslands and savannas and extends to areas of similar habitat in Eritrea, Sudan, and Djibouti. This woodland belt has several natural plant communities, but has mostly been heavily grazed and converted to agricultural use now. Kolla, is an open woodland found at lower elevations, and dominated by species of Terminalia, Commiphora, Boswellia, and Acacia. Weyna dega is a woodland found in moister and higher locations, dominated by the conifers Afrocarpus gracilior and Juniperus procera. The lower portion of the Harenna Forest is a distinct woodland community, with an open canopy of Warburgia ugandensis, Croton macrostachyus, and Syzygium guineense, and Afrocarpus gracilior, with wild coffee (Coffea arabica) as the dominant understory shrub. The southwesterly winds bring rainfall from May to October with moisture from the Red Sea coming in from the east year round. Fauna at these elevations includes the endemic Harwood's francolin (Francolinus harwoodi), Prince Ruspoli's turaco (Tauraco ruspolii) and yellow-throated seedeater (Serinus flavigula), along with the Djibouti francolin (Francolinus ochropectus) in the Djibouti hills that are in the same general ecoregion.[7]

The Ethiopian montane grasslands and woodlands is the largest of the highland ecoregions, occupying the area between 1,800 and 3,000 meters' elevation. The natural vegetation was closed-canopy forest in moister areas, and grassland, bushland, and thicket in drier areas. However these hillsides have good fertile soil and are heavily populated, largely by farming communities so most of the region has been converted to agriculture with a few areas of natural vegetation remaining. Urban areas in this ecoregion include: Ethiopia's capital city and Africa's fourth largest city Addis Ababa, the Amhara Region capital Bahir Dar with its island monasteries on Lake Tana, the old walled city of Harar, the spa town of Ambo, Asella in the Arsi Zone, the trekking center of Dodola, the lakeside Debre Zeyit, the largest city in the southwest Jimma, the market town of Nekemte, and the capital of the Tigray Region, Mek'ele. Awash National Park is a site for birdwatching.

Remaining woodland in the drier areas contains much endemic flora and primarily consists of Podocarpus conifers and Juniperus procera, often with Hagenia abyssinica. In the Harenna Forest, pockets of moist, closed-canopy forest with Pouteria and Olea are draped with lianas and epiphytes, while above 2400 metres, a shrubby zone is home to Hagenia, Schefflera, and giant lobelias (Lobelia gibberroa), species which can be found on the East African mountains further south. The evergreen broadleaved forest of the Semien Mountains, between 2,300 and 2,700 meters' elevation, is dominated by Syzygium guineense, Juniperus procera, and Olea africana.

As the lower slopes of the mountains are so heavily populated even the high altitude moorlands are affected by human interference, such as the grazing of livestock and even farming. There are two protected areas of high moorland: Bale Mountains National Park in the southern highlands, accessible from Dinsho; and Simien Mountains National Park, accessible from Gondar, which includes Ras Dashen. However even these parks are losing habitat to livestock grazing, while the lower elevation parks (Harar Wildlife Sanctuary, Awash National Park, Omo National Park, and Nechisar National Park) are even less secure.

Fauna

These slopes are home to a number of endemic reptiles, birds and animals, including the endangered walia ibex (Capra walie) and the gelada baboon, whose thick fur allows it to thrive in the cooler climates of the mountains. These two species are only found on the northern side of the valley while another rare endemic the mountain nyala (Tragelaphus buxtoni) is restricted to the southern side, and now survives at higher altitudes than its original habitat as the lower slopes are heavily farmed. More widespread mammals found here include the mantled guereza (Colobus guereza), which is also threatened as its habitat disappears as is that of many other mammals of the highlands such as olive baboon (Papio anubis), Egyptian wolf (Canis aureus), leopard (Panthera pardus), lion (Panthera leo), spotted hyena (Crocuta crocuta), caracal (Caracal caracal), serval (Leptailurus serval), common duiker (Sylvicapra grimmia) and giant forest hog (Hylochoerus meinertzhageni). Birds include Rueppell's chat, the finch Ankober serin (Serinus ankoberensis), white-winged flufftail (Sarothrura ayresi), and blue-winged goose. The farmland is home to many butterflies, especially Papilio, Charaxinae, Pieridae and Lycaenidae.

Above 3,000 meters' elevation lie the high Ethiopian montane moorlands, the largest afroalpine region in Africa. The montane moorlands lie above the tree line, and consist of grassland and moorland with abundant herbs and some shrubs that have adapted to the high mountain conditions. There are several endemic animal species one of which, the Ethiopian wolf (Canis simensis), is critically endangered. Other endemics include the big-headed mole-rat (Tachyoryctes macrocephalus) which is common on the Sanetti Plateau in the Bale Mountains. The mountain nyala finds its way up to the high moorlands although it is more common at lower elevations. Wintering birds include wigeon (Anas penelope), shoveler (Anas clypeata), ruff (Philomachus pugnax) and greenshank (Tringa nebularia).

Other fauna in the area also includes aardvark, eagle, Ethiopian wolf, Egyptian wolf, gelada, secretarybird, Nubian ibex, and marabou stork and Ethiopian endemic species such as the shrew (Crocidura harenna), the narrow-footed woodland mouse (Grammomys minnae) and Menelik's bushbuck (Tragelaphus scriptus meneliki), which is a subspecies with long, dark fur.

See also

References

  1. ^ Paul B. Henze, Layers of Time (New York: Palgrave, 2000), p. 2.
  2. ^ a b Oxford English Dictionary, 1st ed. "coffee, n." Oxford University Press (Oxford), 1891.
  3. ^ Weinberg & Bealer 2001, p. 25
  4. ^ January 2005: The Ethiopian Large Igneous Province
  5. ^ a b c Coltorti, M.; Dramis, F.; Ollier, C.D. (2007). "Planation surfaces in Northern Ethiopia". Geomorphology. 89: 287–296.
  6. ^ An explanation of this unusual rain pattern can be found at Ethiopia: Drought intensifies during corn and sorghum harvest (ReliefWeb)
  7. ^ http://worldwildlife.org/ecoregions/at0112

External links

Coordinates: 12°32′00″N 41°23′8″E / 12.53333°N 41.38556°E

Akobo River

The Akobo River is a river on the border between South Sudan and Ethiopia. From its source in the Ethiopian Highlands near Mizan Teferi it flows west for 434 kilometres (270 mi) to join the Pibor River. The Pibor flows into the Sobat River, which in turn empties into the White Nile.

The tributaries of the Akobo river include the Cechi, the Chiarini, and the Owag, on the right or Ethiopian side; and the Neubari, Ajuba and Kaia on the left or South Sudanese side.

Amhara Region

Amhara Region (Ge'ez: አምሓራ, Amharic: አማራ, romanized: ʾÄmara) is one of the nine ethnic divisions of Ethiopia, containing the homeland of the Amhara people. Previously known as "Region 3", its capital is Bahir Dar. Ethiopia's largest inland body of water, Lake Tana, which is the source of the Blue Nile river, is located within Amhara. The region also contains the Semien Mountains National Park, which includes Ras Dashan, the highest point in Ethiopia. Amhara is bordered by the state of Sudan to the west and northwest, and in other directions by other regions of Ethiopia: Tigray to the north, Afar to the east, Benishangul-Gumuz to the west and southwest, and Oromia to the south.

The government of Amhara is composed of the executive branch, led by the President; the legislative branch, which comprises the State Council; and the judicial branch, which is led by the state Supreme Court.

Bale Mountains

The Bale Mountains (also known as the Urgoma Mountains), in the Oromia Region of southeast Ethiopia, south of the Awash River, are part of the Ethiopian Highlands. They include Tullu Demtu, the second-highest mountain in Ethiopia (4377 meters), and Mount Batu (4307 meters). The Weyib River, a tributary of the Jubba River, rises in these mountains east of Goba. The Bale Mountains National Park covers 2,200 square kilometers of these mountains. The main attractions of the park are the wild alpine scenery, and the relative ease with which visitors can see unique birds and mammals.

Bale shrew

The Bale shrew (Crocidura bottegoides) is a species of mammal in the family Soricidae.

It is endemic to Ethiopia, in the Bale Mountains of the Ethiopian Highlands.

Its natural habitats are subtropical or tropical moist montane forests and subtropical or tropical high-altitude grassland.

It is threatened by habitat loss.

Baro River

The Baro River (Amharic: ባሮ ወንዝ Baro/Openo Wenz, known to the Anuak as Openo River) is a river in southwestern Ethiopia, which defines part of Ethiopia's border with South Sudan. From its source in the Ethiopian Highlands it flows west for 306 kilometres (190 mi) to join the Pibor River. The Baro-Pibor confluence marks the beginning of the Sobat River, a tributary of the White Nile.The Baro and its tributaries drain a watershed 41,400 km2 (16,000 sq mi) in size. The river's mean annual discharge at its mouth is 241 m³/s (8,510 ft³/s).

Coffea arabica

Coffea arabica (), also known as the Arabian coffee, "coffee shrub of Arabia", "mountain coffee" or "arabica coffee", is a species of Coffea. It is believed to be the first species of coffee to be cultivated, and is the dominant cultivar, representing some 60% of global production. Coffee produced from the (less acidic, more bitter, and more highly caffeinated) robusta bean (C. canephora) makes up most of the remaining coffee production. Arabica coffee's first found in Yemen and documented by the 12th century. Coffea arabica is called būna in Arabic.

Danakil Alps

The Danakil Alps are a highland region in Ethiopia and Eritrea with peaks over 1000 metres in height and a width varying between 40 and 70 kilometres. The alps lie to the east of the Danakil Depression and separate it from the southern Red Sea. A rift escarpment facing the Red Sea forms the eastern boundary of the range.

Geologically these highlands are described as a horst and are sometimes referred to as the Danakil Horst or Danakil Block. They were formed by geological faulting which has occurred since the Miocene epoch. There is Precambrian basement rock underlying the region and in coastal Eritrea Precambrian and Mesozoic rocks are exposed. The basement rock of the alps has become overlaid with flood basalt since the Oligocene epoch. About 20 million years ago the Afar rift zone opened up. This resulted in the alps breaking away from the Ethiopian plateau to which they had previously been attached and drifting to the east/northeast.The Danakil Alps contains many volcanic edifices, such as those forming the Nabro Volcanic Range. The largest of the Nabro Volcanic Range edifices are the Mallahle, Nabbro, and Dubbi. The volcanic range extends northwestward to the Red Sea, ending with the Kod Ali volcano offshore.The Danakil Alps have been cut off from the sea since the late Pleistocene.

Ethiopian highland hare

The Ethiopian highland hare (Lepus starcki) is a medium-sized species of mammal in the rabbit and hare family, Leporidae. Its dorsal pelage is grizzled, buff white and spotted and streaked with black, while its belly fur is pure white and fluffy. It is endemic to the Ethiopian Highlands, ranging over the Afroalpine regions of the Shoa, Bale, and Arsi Provinces of Ethiopia. A herbivore, it mostly feeds on moorland grasses. The IUCN rates it as a species of least concern.

Lake Ashenge

Lake Hashenge (also ፃዕዳ ባሕሪ Lake Ashangi, Lake Ashenge) is a lake in the southern Tigray Region of Ethiopia. Located in the Ethiopian highlands at an elevation of 2409 meters, it has no outlet. According to the Statistical Abstract of Ethiopia for 1967/68, Lake Ashenge is five kilometers long and four wide, with a surface area of 20 square kilometers.

The British explorer Henry Salt, who notes that the Tigrinya name of the lake is Tsada Bahri ("White Sea") from the number of birds which cover its surface, records a local tradition that a large city once stood on the site of Ashenge, but "it was destroyed, in his displeasure, by the immediate hand of God."

Lake Tana

Lake Tana (also spelled T'ana, Amharic: ጣና ሀይቅ, Ṭana Ḥäyq, T’ana Hāyk’; an older variant is Tsana, Ge'ez: ጻና Ṣānā; sometimes called "Dembiya" after the region to the north of the lake) is the source of the Blue Nile and is the largest lake in Ethiopia. Located in Amhara Region in the north-western Ethiopian Highlands, the lake is approximately 84 kilometres (52 miles) long and 66 kilometres (41 miles) wide, with a maximum depth of 15 metres (49 feet), and an elevation of 1,788 metres (5,866 feet). Lake Tana is fed by the Lesser Abay, Reb and Gumara rivers. Its surface area ranges from 3,000 to 3,500 square kilometres (1,200 to 1,400 square miles), depending on season and rainfall. The lake level has been regulated since the construction of the control weir where the lake discharges into the Blue Nile. This controls the flow to the Blue Nile Falls (Tis Abbai) and hydro-power station.

In 2015, the Lake Tana region was nominated as a UNESCO Biosphere Reserve recognizing its national and international natural and cultural importance.

MacMillan's shrew

The MacMillan's shrew (Crocidura macmillani) is a species of mammal in the family Soricidae.

It is endemic to the Ethiopian Highlands in western Ethiopia.

Its natural habitats are subtropical or tropical moist montane forests, and moist savanna. It is threatened by habitat loss.

Mille River

The Mille River is a river of Ethiopia and a tributary of the Awash. It drains parts of the Semien (North) Wollo and Debub (South) Wollo Zones of the Amhara Region, as well as Administrative Zone 4 of the Afar Region. The explorer L.M. Nesbitt, who travelled through the area in 1928, was impressed by its size, and described the Mille as "probably the only real river which joins the Awash". The Ala River (A'ura) and Golima River (Golina) are small tributaries of the Mille.The Mille River rises in the Ethiopian highlands west of Sulula in Tehuledere woreda. It flows first to the north, then curves to run east to its confluence with the Awash at 11°25′N 40°58′E.

Oromia Region

The Oromia Region (Oromo: Oromiyaa) is one of the nine ethnically-based regional states of Ethiopia, the homeland of the Oromo. It is bordered by the Somali Region to the east; the Amhara Region, the Afar Region and the Benishangul-Gumuz Region to the north; South Sudan, Gambela Region, and Southern Nations, Nationalities, and Peoples' Region to the west; and Kenya to the south. The 2011 census reported the population of Oromia as 35,000,000; this makes it the largest regional state in population.

Oromia includes the former Arsi Province along with portions of the former Bale, Hararghe, Illubabor, Kaffa, Shewa and Sidamo provinces. Towns in the region include Adama, Ambo, Asella, Badessa, Bale Robe, Bishoftu, Begi, Chiro, Dembidolo, Fiche, Gimbi, Goba, Haramaya, Jimma, Metu, Negele Borana, Moyale, Nekemte, Sebeta, Shashamane, and Waliso, among many others.

Semien Mountains

The Semien Mountains (Amharic: ስሜን ተራሮች) (or Səmen; also spelled Simien and Simen), in northern Ethiopia, north east of Gondar in Amhara region, are part of the Ethiopian Highlands. They are a World Heritage Site and include the Simien Mountains National Park. The mountains consist of plateaus separated by valleys and rising to pinnacles. The tallest peak is Ras Dejen (4,550 m); other notable heights include Mounts Biuat (4,437 m) and Kidis Yared (4,453 m).

Because of their geological origins, the mountains are almost unique, with only South Africa's Drakensberg having been formed in the same manner and thus appearing similar. Notable animals in the mountains include the walia ibex, gelada, and caracal. There are a few Ethiopian wolves.

Swainson's sparrow

Swainson's sparrow (Passer swainsonii) is a species of bird in the sparrow family Passeridae. Sometimes considered a subspecies of the grey-headed sparrow, it occurs in northeastern Africa, largely in the Ethiopian Highlands. This sparrow was named after the English naturalist and illustrator William John Swainson.

Theropithecus

Theropithecus is a genus of primates in the family Cercopithecidae. It contains a single living species, the gelada, (Theropithecus gelada), native to the Ethiopian Highlands.

Additional species are known from fossils, including:

Theropithecus brumpti

Theropithecus darti

Theropithecus oswaldi

Wattled ibis

The wattled ibis (Bostrychia carunculata) is a species of bird in the family Threskiornithidae. It is endemic to the Ethiopian highlands and is found only in Ethiopia and Eritrea.

Yellow-fronted parrot

The yellow-fronted parrot (Poicephalus flavifrons) is endemic to the Ethiopian Highlands. It is a mostly green parrot with a yellow head. Relatively little is known about this bird.

Yellow bishop

The yellow bishop, Cape bishop, Cape widow or yellow-rumped widow (Euplectes capensis) is a resident breeding bird species in Angola, Botswana, Burundi, Cameroon, Congo, Equatorial Guinea, Ethiopia, Kenya, Lesotho, Malawi, Mozambique, Nigeria, Rwanda, South Africa, South Sudan, Swaziland, Tanzania, Uganda, Zambia and Zimbabwe.This common weaver occurs in less arid vegetated areas, such as fynbos, moist grassland and bracken-covered valleys at altitudes from sea level to the Ethiopian highlands.

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