Rwenzori Mountains

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Rwenzori Mountains
1172 ruwenzori.jpg
Highest point
Peak Mount Stanley
Elevation 5,109 m (16,762 ft)
Dimensions
Length 120 km (75 mi)
Geography
Country Uganda, Democratic Republic of the Congo

The Rwenzori Mountains, previously called the Ruwenzori Range (spelling changed c. 1980 to conform more closely with the local name "Rwenjura"), and sometimes the Mountains of the Moon, is a mountain range of eastern Equatorial Africa, located on the border between Uganda and the Democratic Republic of the Congo.

The Rwenzori Mountains reach heights up to 5,109 m (16,761 ft) at 0°23′09″N 29°52′18″E / 0.38583°N 29.87167°E / 0.38583; 29.87167Coordinates: 0°23′09″N 29°52′18″E / 0.38583°N 29.87167°E / 0.38583; 29.87167. The highest Rwenzori peaks are permanently snow-capped, and along with Mount Kilimanjaro and Mount Kenya are the only such ones in Equatorial Africa.[citation needed] Rwenzori Mountains National Park and Virunga National Park are located in the range.

Geology[edit]

Margherita Peak on Mount Stanley is the highest point in the range

The mountains formed about three million years ago in the late Pliocene, as a result of an uplifted block of crystalline rocks including: gneiss, amphibolite granite, and quartzite.[1] They are on the flanks of the Albertine Rift, the western branch of the East African Rift.

This uplift divided the paleolake Obweruka and created three of the present-day African Great Lakes: Lake Albert, Lake Edward,[1] and Lake George.[2]

The range is about 120 km (75 mi) long and 65 km (40 mi) wide. It consists of six massifs separated by deep gorges: Mount Stanley (5,109m), Mount Speke (4,890m), Mount Baker (4,843m), Mount Emin (4,798m), Mount Gessi (4,715m) and Mount Luigi di Savoia (4,627m).[3] Mount Stanley is the largest and has several subsidiary summits, with Margherita Peak being the highest point. The rock is metamorphic, and the mountains are believed to have been tilted and squeezed upwards by plate movement. They are in an extremely humid area, and frequently enveloped in clouds.

Human history[edit]

House and people in Kasese District, Uganda

In 150 CE the Alexandrian Greek geographer Ptolemy referred to a snowcapped massif in the heart of Africa by the name of Selenes oros, Latinized as "Lunae Montes", in English Mountains of the Moon. These are now widely accepted to be the Rwenzori Mountains.

Panoramic aerial view of Rwenzori Mountains, 1934

The first modern European sighting of the Rwenzori was by the expedition of Henry Morton Stanley in 1889 (the clouds possibly being the reason two decades of previous explorers had not seen them). On June 7, the expedition's second-in-command and its military commander, William Grant Stairs, climbed to 3,254 metres (10,676 ft), the first known non-African ever to climb in the range. John Edmund Sharrock Moore reached the snowline in 1900, attaining 14,900 feet and proved the existence of permanent glaciers. The first ascent to the summit was made by the Duke of the Abruzzi in 1906. His expedition quickly made first ascents of all major snow and ice peaks, mapping their complex geography, and leaving them with Italian names. His team consisted of mountain guides, biologists, surveyors, a geologist, photographers, and some one hundred and fifty porters. Photographer Vittorio Sella took a number of photographs showing a now-vanished world. Sella's photographic work is conserved at the Museo Nazionale della Montagna, in Torino, and at the Istituto di Fotografia Alpina Vittorio Sella, in Biella, both in Italy. The Makerere University, Uganda, also has a selection of his images.[4]

The Rwenzori range is the home of the Konjo and Amba peoples. In the early 1900s, these two tribes were added to the Toro Kingdom by the colonial powers. The Konjo and Amba began to agitate for separation from Toro in the 1950s, a movement that became Rwenzururu, an armed secessionist movement, by the mid-1960s. The insurgency ended through a negotiated settlement in 1982, though the Rwenzururu Kingdom was acknowledged by the government in 2008.

Natural history[edit]

Flora[edit]

Lower Bigo Bog at 3400m in the Rwenzori Mountains with giant lobelia in foreground.

The Rwenzori are known for their vegetation, ranging from tropical rainforest through alpine meadows to snow. The range supports its own species and varieties of giant groundsel and giant lobelia and even has a six metre high heather covered in moss that lives on one of its peaks. Most of the range is now a World Heritage Site and is covered jointly by the Rwenzori Mountains National Park in southwestern Uganda, and the Virunga National Park in the eastern Democratic Republic of the Congo.[3]

Although the flora in the Rwenzori is closely related to that of other East-African high mountains it is much more luxuriant here. This is mainly a result of the high and regular rainfall in the area. The distribution of vegetation is for a good deal determined by the altitude. At higher elevations, certain genera of plants grow unusually large. Most surprising are the giant heathers, senecios and lobelias, to which the Swedish botanist Olov Hedberg from the Uppsala University referred to as “botanical big game”. As the altitude increases, temperatures drop. The air also grows thinner, provoking intense radiation, even on clouded days. During the day the incoming radiation of ultraviolet and infrared light is fierce, while at night the outward radiation under a clear sky has a considerable cooling effect. The equatorial location dictates marked diurnal variations in temperature, whereas the seasonal differences are less important, as if it were summer every day, winter every night.

There is no water shortage in the Rwenzori. Yet several members of the afroalpine family bear resemblance with species that normally thrive in desert climates. The reason lies in their similar water economy. Although abundantly present, water is not always readily available to the afroalpine plants when they need it. The nightly frosts affect the sap transport in the plants, and the intake of water by its roots. As the day begins, the air temperature and radiation level rise rapidly, putting strenuous demands on the exposed parts of the plants. It is vital to meet the transpiration demands of the leaves, and maintain a proper water balance. To counter the effects of freezing, the afroalpine plants have developed the insulation systems which give them such a striking appearance. As a rule, these adaptive trends become more prominent as the altitude rises.[4]

Vegetation zones
There are 5 different vegetation zones found in the Rwenzori Mountains. These are grassland (1000–2000m), montane forest (2000–3000m), bamboo/mimulopsis zone (2500–3500m), heather/Rapanea zone (3000–4000m) and the afro-alpine moorland zone (4000–4500m). At higher altitudes some plants reach an unusually large size, such as lobelia and groundsels. The vegetation in the Rwenzori Mountains is unique to equatorial alpine Africa.[5]
Flora vs altitude
Meters
Order
1500 2000 2500 3000 3200 3400 3600 3800 4000 4200 4400 4600 4800 5000 5100
Lamiales Mimulopsis elliotii
Mimulopsis arborescens
Rosales Prunus africana Hagenia abyssinica
Alchemilla subnivalis
Alchemilla stuhlmanii
Alchemilla triphylla
Alchemilla johnstonii
Alchemilla argyrophylla
Fabales Albizia gummifera
Cornales Alangium chinense
Malpighiales Casearia battiscombei
Croton macrostachyus
Neoboutonia macrocalyx
Symphonia globulifera
Hypericum sp
Hypericum revolutum
Hypericum bequaertii
Asparagales Scadoxus cyrtanthiflorus
Disa stairsii
Asterales Dendrosenecio erici-rosenii
Dendrosenecio adnivalis
Helichrysum sp.
Lobelia bequaertii
Lobelia wollastonii
Helichchrysum guilelmii
Helichchrysum stuhlmanii
Senecio transmarinus
Senecio mattirolii
Apiales Peucedanum kerstenii
Myrtales Syzygium guineense
Sapindales Allophylus abyssinicus
Gentianales Tabernaemontana sp. Galium ruwenzoriense
Ericales Pouteria adolfi-friedericii Erica arborea
Erica trimera
Erica silvatica
Erica johnstonii
Brassicales Subularia monticola
Primulales Rapanea rhododendroides
Ranunculales Ranunculus oreophytus
Arabis alpina
Santalales Strombosia scheffleri
Poales Yushania alpina Carex runssoroensis
Festuca abyssinica
Poa ruwenzoriensis
Lecanorales Usnea
Order
Meters
1500 2000 2500 3000 3200 3400 3600 3800 4000 4200 4400 4600 4800 5000 5100

Sources: [5][6][7]

Fauna[edit]

The range is known for its animal populations, including forest elephants, several primate species, and many endemic birds.

Glacial recession in Rwenzori[edit]

Ornithologist James P. Chapin on a Rwenzori expedition under flag of The Explorers Club, 1925

A subject of concern in recent years has been the impact of climate change on Rwenzori's glaciers. In 1906 the Rwenzori had 43 named glaciers distributed over six mountains with a total area of 7.5 square kilometres (2.9 sq mi), about half the total glacier area in Africa. By 2005 less than half of these were still present, on only three mountains, with an area of about 1.5 square kilometres (0.58 sq mi). Recent scientific studies, such as those by Dr. Richard Taylor of University College London, have attributed this retreat to global climate change and have investigated the impact of this change on the mountain's vegetation and biodiversity.[8][9]

See also[edit]

Notes[edit]

  1. ^ a b "Climate Change and the Aquatic Ecosystems of the Rwenzori Mountains". Makerere University and University College London. 2007-09-15. Retrieved 2014-02-02. 
  2. ^ Wayland, E. J. (July–Dec 1934). "Rifts, Rivers, Rains and Early Man in Uganda". Journal of the Royal Anthropological Institute (Royal Anthropological Institute of Great Britain and Ireland) 64: 333–352. doi:10.2307/2843813. JSTOR 2843813. 
  3. ^ a b "Rwenzori Mountains National Park". Rwenzori Abruzzi. 2006-05-27. Archived from the original on 2008-03-05. Retrieved 2008-05-06. 
  4. ^ a b Flowers of the Moon, Afroalpine vegetation of the Rwenzori Mountains, Schutyser S., 2007, 5 Continents Editions, ISBN 978-88-7439-423-4.
  5. ^ a b H. Peter Linder and Berit Gehrke (2 March 2006). "Common plants of the Rwenzori, particularly the upper zones" (PDF). Institute for Systematic Botany, University of Zurich. Archived from the original on 2008-05-30. Retrieved 2008-05-06. 
  6. ^ "RWENZORI MOUNTAINS NATIONAL PARK, UGANDA". Protected Areas and World Heritage. United Nations Environment Programme. March 1994. Archived from the original on 2008-03-25. Retrieved 2008-05-08. 
  7. ^ "Forest Resources of Tropical Africa". Tropical Forest Resources Assessment Project (reprint ed.). Food and Agriculture Organization of the United Nations. 1984. UN 32/6.1301–78–04. Retrieved 2008-05-12. 
  8. ^ Tom Knudson, [In the Mountains of the Moon, A Trek to Africa’s Last Glaciers], Yale Environment 360 Report, 4 Feb 2010
  9. ^ [Rwenzori Glaciers (East Africa)], Tropical Glaciology Group, Innsbruck University

References[edit]

External links[edit]