Rwenzori Mountains

Rwenzori Mountains
Highest point
Peak	Mount Stanley
Elevation
Coordinates
Dimensions
Length
Geography
Rwenzori Mountains
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 support glaciers and are the source of the Nile river.

The Rwenzori Mountains reach heights up to 5,109 m (16,761 ft). The highest Rwenzori peaks are permanently snow-capped, and along with Mount Kilimanjaro and Mount Kenya are the only such ones in Equatorial Africa. Rwenzori Mountains National Park and Virunga National Park are located in the range.

Geology

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. 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, and Lake George.

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). 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

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 previous explorers over two decades 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 Turin, 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.

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

Flora

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.

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, 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.

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.

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:

Fauna

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

Glacial recession in Rwenzori

Main article: Retreat of glaciers since 1850 § Tropical glaciers

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.

See also

• 1966 Toro earthquake

Notes

References

• Glaciers of the Middle East and Africa, Williams, Richard S., Jr. (editor) In: U. S. Geological Survey Professional Paper, 1991, pp.G1-G70
• Guide to the Ruwenzori, Osmaston,H.A., Pasteur,D. 1972, Mountain Club of Uganda. 200 p.
• Recession of Equatorial Glaciers. A Photo Documentation, Hastenrath, S., 2008, Sundog Publishing, Madison, WI, ISBN 978-0-9729033-3-2, 144 pp.
• Tropical Glaciers, Kaser, G., Osmaston, H.A. 2002, Cambridge University Press, UK. 207 p.
• Ruwenzori, de Filippi, F. 1909. Constable, London. 408 p.
• Greenpeace article "The Death of the Ice Gigantaurs"
• BBC Article "Fabled ice field set to vanish"
• Dr Taylor's Homepage, with information about the impact of climate change on Rwenzori.
• Kaser et al. 2006, in International Book of Climatology 24: 329–339 (2004)

External links

• UWM.edu: 1937 aerial photographs of Rwenzori Mountains — University of Wisconsin-Milwaukee Libraries Digital Collections.
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