The Nimba Range forms part of the southern extent of the Guinea Highlands, adjacent to the Toura Mountains. The highest peak is Mount Nimba on the

border Borders are generally defined as geography, geographical boundaries, imposed either by features such as oceans and terrain, or by polity, political entities such as governments, sovereign states, federated states, and other administrative divisio ...

Liberia Liberia, officially the Republic of Liberia, is a country on the West African coast. It is bordered by Sierra Leone to Liberia–Sierra Leone border, its northwest, Guinea to Guinea–Liberia border, its north, Ivory Coast to Ivory Coast–Lib ...

Ivory Coast Ivory Coast, also known as Côte d'Ivoire and officially the Republic of Côte d'Ivoire, is a country on the southern coast of West Africa. Its capital city of Yamoussoukro is located in the centre of the country, while its largest List of ci ...

and

Guinea Guinea, officially the Republic of Guinea, is a coastal country in West Africa. It borders the Atlantic Ocean to the west, Guinea-Bissau to the northwest, Senegal to the north, Mali to the northeast, Côte d'Ivoire to the southeast, and Sier ...

, at , and at the intersection of the Nimba and Toura Mountains. "Mount Nimba" may refer either to Mount Richard-Molard or to the entire range. Other peaks include Grand Rochers at , Mont Sempéré at , Mont Piérré Richaud at , Mont Tô at , and Mont LeClerc , all of them are located in Guinea. Mount Nimba Strict Nature Reserve of Guinea and Ivory Coast covers significant portions of the Nimba Range.

Geology

The Nimba Range is a narrow ridge extending approximately 40 km long, with an orientation of northeast–southwest. It is composed mostly of

Precambrian The Precambrian ( ; or pre-Cambrian, sometimes abbreviated pC, or Cryptozoic) is the earliest part of Earth's history, set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian, the first period of t ...

rock, including

granite Granite ( ) is a coarse-grained (phanerite, phaneritic) intrusive rock, intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly coo ...

and quartzite which contain deposits of

iron ore Iron ores are rocks and minerals from which metallic iron can be economically extracted. The ores are usually rich in iron oxides and vary in color from dark grey, bright yellow, or deep purple to rusty red. The iron is usually found in the f ...

. Mining of top-quality iron-ore poses the major threat to the unique geomorphology and wildlife. There are about fifty springs, including the origins of the Cavally, Cestos, and Sassandra Rivers.

Climate

Rainfall varies greatly with elevation and season. About 3,000 mm of rain falls at the highest altitudes, and between 700 and 1,200 mm at the lower elevations. In fact, some parts of the mountain receive less precipitation, due to rain-shadow effect of the high ridge. Most of the rainfall occurs between May and October.

Ecology

The Nimba Range harbours an especially rich flora and fauna, and it is the home of more than 2000

vascular plant Vascular plants (), also called tracheophytes (, ) or collectively tracheophyta (; ), are plants that have lignin, lignified tissues (the xylem) for conducting water and minerals throughout the plant. They also have a specialized non-lignified Ti ...

species, 317

vertebrate Vertebrates () are animals with a vertebral column (backbone or spine), and a cranium, or skull. The vertebral column surrounds and protects the spinal cord, while the cranium protects the brain. The vertebrates make up the subphylum Vertebra ...

species, 107 of which are

mammal A mammal () is a vertebrate animal of the Class (biology), class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three ...

s, and to more than 2,500

invertebrate Invertebrates are animals that neither develop nor retain a vertebral column (commonly known as a ''spine'' or ''backbone''), which evolved from the notochord. It is a paraphyletic grouping including all animals excluding the chordata, chordate s ...

species. Notably

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

vertebrates are Nimba viviparous toad, Lamotte's roundleaf bat, '' Myotis nimbaensis'', and Nimba otter shrew. Other rare and endangered animals are West African lion,

pygmy hippopotamus The pygmy hippopotamus or pygmy hippo (''Choeropsis liberiensis'') is a small Hippopotamidae, hippopotamid which is native to the forests and swamps of West Africa, primarily in Liberia, with small populations in Sierra Leone, Guinea, and Ivory Co ...

, zebra duiker, and western chimpanzee that uses stones as tools. The range has been designated an Important Bird Area (IBA) by

BirdLife International BirdLife International is a global partnership of non-governmental organizations that strives to conserve birds and their habitats. BirdLife International's priorities include preventing extinction of bird species, identifying and safeguarding i ...

because it supports significant populations of many bird species. Terrestrial ecoregions include Western Guinean lowland forest, Guinean montane forest, Guinean forest-savanna mosaic, and West Sudanian savanna. The Nimba Range is a part of a distinct freshwater ecoregion with a high portion of endemic aquatic species.

Terrestrial

The plant communities vary with altitude and cardinal orientation. The Guinean montane forests ecoregion covers the portion of the range above 600 meters elevation. Major plant communities in the ecoregion include montane grasslands and savannas, cloud forests, and lower montane forests. High-altitude grasslands and montane savannas cover the highest peaks, dominated by the grass ''

Loudetia kagerensis ''Loudetia'' is a genus of African, Arabian, and South American plants in the Poaceae, grass family.Asplenium schnellii'', and two endemic flowering plants, '' Osbeckia porteresii'' and '' Blaeria nimbana''. Shrubs, including '' Protea occidentalis'', inhabit the slopes."Mount Nimba Strict Nature Reserve, Guinea and Côte d'Ivoire". Encyclopedia of Earth. Accessed November 10, 2012

/ref> The endemic frog species '' Nimbaphrynoides occidentalis,'' which inhabits the montane grasslands of the range, is totally viviparous. The Guinea Screeching Frog ('' Arthroleptis crusculum'') is a threatened species found on Mt. Nimba and other peaks in the Guinea Highlands. It is found in high-altitude grassland and in gallery forests during the dry season. '' Ptychadena submascareniensis'' is another frog species that has been found only on Mount Nimba and in the Loma Mountains of

Sierra Leone Sierra Leone, officially the Republic of Sierra Leone, is a country on the southwest coast of West Africa. It is bordered to the southeast by Liberia and by Guinea to the north. Sierra Leone's land area is . It has a tropical climate and envi ...

. Below the highest peaks, montane grasslands interspersed by gallery forests, between 1,200 and 1,400 meters. Above 900 meters elevation, near-daily mist and clouds support cloud forests, dominated by the Guinea Plum tree ('' Parinari excelsa''), trees of the Myrtle family (

Myrtaceae Myrtaceae (), the myrtle family, is a family of dicotyledonous plants placed within the order Myrtales. Myrtle, pōhutukawa, bay rum tree, clove, guava, acca (feijoa), allspice, and eucalyptus are some notable members of this group. All ...

), including '' Syzygium guineense'', and species of '' Ochna'' and '' Gaertnera''. The moist climate supports many

epiphyte An epiphyte is a plant or plant-like organism that grows on the surface of another plant and derives its moisture and nutrients from the air, rain, water (in marine environments) or from debris accumulating around it. The plants on which epiphyt ...

s, including an endemic

orchid Orchids are plants that belong to the family Orchidaceae (), a diverse and widespread group of flowering plants with blooms that are often colourful and fragrant. Orchids are cosmopolitan plants that are found in almost every habitat on Eart ...

, '' Rhipidoglossum paucifolium''. Lower montane forests of '' Lophira procera'', '' Tarrietia utilis'', '' Mapania'' spp., '' Chlorophora regia'', '' Morus mesozygia'', and '' Terminalia ivorensis'' occur between 600 and 900 meters elevation. Below 600 meters, the montane forests transition to the Western Guinean lowland forests ecoregion. The mountain is surrounded by Guinean forest-savanna mosaic, and West Sudanian savanna.

Freshwater

Swift-running streams descend steep slopes of the range, and often experience torrential floods during the rainy season. Rheophytes, plants that can live in running water, dominate the aquatic vegetation. The endemic aquatic animals in the Nimba Range includes frogs, fish, the Nimba Stream Crab ''(Liberonautes nimba)'', and the endangered Nimba otter shrew ''(Micropotamogale lamottei)''. The African clawless otter ''(Aonyx capensis)'' also inhabits the mountain streams. Species richness is high among aquatic invertebrates, including 81 species of dragonflies. The WWF designates the Nimba Range a distinct freshwater ecoregion because of its moderate species richness and high proportion of

aquatic species, particularly among fish and amphibians. The Nimba Range's high elevation, its rapids and waterfalls that isolate habitat areas, and the stability of the aquatic environment, have promoted speciation. The Guinean Highlands, of which the Nimba Range are part, separate the coastal rivers and streams of Upper Guinea from the upper

Niger River The Niger River ( ; ) is the main river of West Africa, extending about . Its drainage basin is in area. Its source is in the Guinea Highlands in south-eastern Guinea near the Sierra Leone border. It runs in a crescent shape through Mali, Nige ...

basin. The highlands form a barrier to movement of aquatic species between these freshwater regions. The fish fauna of the Nimba Range shares affinities with that of Upper Guinea."Mount Nimba". Freshwater Ecoregions of the World, accessed November 10, 201

/ref>

Mount Nimba Strict Nature Reserve

In 1943, the colonial government established a Strict Nature Reserve in the Ivory Coast section of the range. It was extended into Guinea the following year. The area remained protected after Guinea and Ivory Coast became independent.

UNESCO The United Nations Educational, Scientific and Cultural Organization (UNESCO ) is a List of specialized agencies of the United Nations, specialized agency of the United Nations (UN) with the aim of promoting world peace and International secur ...

declared Mount Nimba a biosphere reserve in 1980, and a

World Heritage Site World Heritage Sites are landmarks and areas with legal protection under an treaty, international treaty administered by UNESCO for having cultural, historical, or scientific significance. The sites are judged to contain "cultural and natural ...

shortly thereafter.

References

External links

Official website of the Guinean Mount Nimba Strict Nature Reserve

Mount Nimba (Freshwater Ecoregions of the World)

Guinean Montane Forests (Encyclopedia of Earth)

Western Guinean lowland forests (Encyclopedia of Earth)

Guinean forest-savanna mosaic (Encyclopedia of Earth)

Mount Nimba Strict Nature Reserve, Guinea and Côte d'Ivoire (Encyclopedia of Earth)

Mount Nimba Strict Nature Reserve, Guinea and Côte d'Ivoire (UNESCO)

Mount Nimba Strict Nature Reserve, Guinea and Côte d'Ivoire (UNESCO MAB Biosphere Reserves Directory)

{{Coord, 7, 34, N, 8, 28, W, display=title, region:LR_type:mountain_source:GNS-enwiki Afromontane Important Bird Areas of Guinea Ecoregions of Guinea Ecoregions of Ivory Coast Ecoregions of Liberia Freshwater ecoregions of Africa Guinean montane forests Mountain ranges of Guinea Mountain ranges of Ivory Coast Mountain ranges of Liberia Montagnes District