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71-677: The Bambouto massif or Bamboutos Mountains is a group of volcanoes based on a swell in the Cameroon Volcanic Line , located in the Western High Plateau of Cameroon , merging in the north with the Oku Volcanic Field . The large volcanic complex extends in a NE-SW direction for over 50 km, with the highest peaks rising to 2,679 m around the rim of a caldera with diameter 10 km. Lava dating gives ages from 23 to 6 million years ago, with

142-745: A lineament that extends from the Sudan to coastal Cameroon, runs under the continental section of the Cameroon line. It is visible in the Foumban Shear Zone , which was active before and during the opening of the South Atlantic in the Cretaceous period. The western end of the shear zone is obscured by the volcanoes of the Cameroon line, but based on reconstruction of the configuration of South America before it separated from Africa,

213-415: A bright yellow species of caecilian , is endemic to São Tomé. As of 2010, São Tomé and Príncipe , an independent nation, had an estimated population of 167,000, most of whom lived on São Tomé island. The main language is Portuguese , but there are many speakers of Forro and Angolar (Ngola), two Portuguese-based creole languages . The economy is mainly based on tourism. Agriculture is important near

284-556: A cave environment limits an organism's ability to disperse, since caves are often not connected to each other. One hypothesis for how closely related troglobite species could become isolated from one another in different caves is that their common ancestor may have been less restricted to cave habitats. When climate conditions became unfavorable, the ancestral species was extirpated from the surface, but some populations survived in caves, and diverged into different species due to lack of gene flow between them. Isolated islands commonly develop

355-465: A constant amount in a country, as opposed to epidemic diseases, which are exploding in cases. The word was used in biology in 1872 to mean a species restricted to a specific location by Charles Darwin . The less common term 'precinctive' has been used by some entomologists as the equivalent of 'endemic'. Precinctive was coined in 1900 by David Sharp when describing the Hawaiian insects, as he

426-478: A euendemic the vicariance was geologic in nature, such as the movement of tectonic plates, but in a cryptoendemic the disjunct distribution was due to the extinction of the intervening populations. There is yet another possible situation that can cause a disjunct distribution, where a species is able to colonize new territories by crossing over areas of unsuitable habitat, such as plants colonizing an island – this situation they dismiss as extremely rare and do not devise

497-402: A holoendemic is a cosmopolitan species. Stenoendemics, also known as local endemics, have a reduced distribution and are synonymous with the word 'endemics' in the traditional sense, whereas euryendemics have a larger distribution -both these have distributions that are more or less continuous. A rhoendemic has a disjunct distribution . Where this disjunct distribution is caused by vicariance, in

568-437: A limited range. Paleoendemism is more or less synonymous with the concept of a ' relict species ': a population or taxon of organisms that were more widespread or more diverse in the past. A 'relictual population' is a population that currently occurs in a restricted area, but whose original range was far wider during a previous geologic epoch . Similarly, a 'relictual taxon' is a taxon (e.g. species or other lineage) that

639-427: A lower basaltic series and an upper series of trachytes , trachyphonolites and phonolites . The upper part of the massif above 2,000 m has a cool and cloudy climate with 2,510 mm of rainfall annually. Soils are acidic, low in phosphates and relatively infertile. Due to population pressure, farming is carried out on the steep slopes, leading to erosion and further loss of fertility. Cattle are also grazed on

710-513: A much larger area, but died out in most of their range, are called paleoendemic , in contrast to neoendemic species, which are new species that have not dispersed beyond their range. The ginkgo tree, Ginkgo biloba , is one example of a paleoendemic species. In many cases biological factors, such as low rates of dispersal or returning to the spawning area ( philopatry ), can cause a particular group of organisms to have high speciation rates and thus many endemic species. For example, cichlids in

781-522: A name for. Traditionally, none of Myers and de Grave's categories would be considered endemics except stenoendemics. Some environments are particularly conducive to the development of endemic species, either because they allow the persistence of relict taxa that were extirpated elsewhere, or because they provide mechanisms for isolation and opportunities to fill new niches. Serpentine soils act as ' edaphic islands' of low fertility and these soils lead to high rates of endemism. These soils are found in

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852-465: A number of endemics. Many species and other higher taxonomic groups exist in very small terrestrial or aquatic islands, which restrict their distribution. The Devil's Hole pupfish, Cyprinodon diabolis , has its whole native population restricted to a spring that is 20 x 3 meters, in Nevada 's Mojave Desert . This 'aquatic island' is connected to an underground basin; however, the population present in

923-427: A particular place and evaluating the risk of extinction for species. Endemism is also of interest in evolutionary biology , because it provides clues about how changes in the environment cause species to undergo range shifts (potentially expanding their range into a larger area, or becoming extirpated from an area they once lived), go extinct, or diversify into more species. The extreme opposite of an endemic species

994-457: A population of 334,463 inhabitants (2015 Census), most of whom are Bubi . The rest of the population are Fernandinos , Spaniards and immigrants from Río Muni , Nigeria and Cameroon . Cocoa production was once the main export, but has declined in recent years. Farming, fishing and logging remain important. Natural gas is produced in offshore wells, processed on the island and exported via tanker. The Western High Plateau, also called

1065-630: A range known as the Western High Plateau , home to the Cameroonian Highlands forests . Volcanic swells further inland are Manengouba , Bamboutu and the Oku Massif . East of Oku there are further volcanic mountains in the Ngaoundere Plateau , some of which appear to have similar origins. The southernmost island in the chain is Annobón, also known as Pagalu, with an area of about 17.5 km (6.8 sq mi). It

1136-498: A species can lead to endemism in multiple ways. Allopatric speciation , or geographic speciation, is when two populations of a species become geographically separated from each other and as a result develop into different species. In isolated areas where there is little possibility for organisms to disperse to new places, or to receive new gene flow from outside, the rate of endemism is particularly high. For example, many endemic species are found on remote islands , such as Hawaii ,

1207-504: A very restrictive range, due to the unique environmental characteristics. The Kula Volcano , one of the fourteen volcanoes in Turkey , is home to 13 endemic species of plants. Endemics might more easily become endangered or extinct because they are already restricted in distribution. This puts endemic plants and animals at greater risk than widespread species during the rapid climate change of this century. Some scientists claim that

1278-428: A wet season of nine months, and a dry season of three months. During the wet season, humid, prevailing monsoon winds blow in from the west and lose their moisture upon hitting the region's mountains. Average rainfall per year ranges from 1,000 mm (39 in) to 2,000 mm (79 in). High elevations give the region a cooler climate than the rest of Cameroon. For example, the average temperature at Dschang in

1349-625: A wide variety of evolutionary histories, so researchers often use more specialized terms that categorize endemic species based upon how they came to be endemic to an area. Different categorizations of endemism also capture the uniqueness and irreplaceability of biodiversity hotspots differently and impact how those hotspots are defined, affecting how resources for conservation are allocated. The first subcategories were first introduced by Claude P. E. Favager and Juliette Contandriopoulis in 1961: schizoendemics, apoendemics and patroendemics. Using this work, Ledyard Stebbins and Jack Major then introduced

1420-437: A wider distributed taxon that has become reproductively isolated without becoming (potentially) genetically isolated – a schizoendemic has the same chromosome count as the parent taxon it evolved from. An apoendemic is a polyploid of the parent taxon (or taxa in the case of allopolyploids ), whereas a patroendemic has a lower, diploid chromosome count than the related, more widely distributed polyploid taxon. Mikio Ono coined

1491-422: Is open canopy montane forest above 1,500 m (4,900 ft) on Pico Basilé, Gran Caldera de Luba and Pico Biao, with subalpine grassland above 2,500 m (8,200 ft). Bioko has exceptional numbers of endemic species of flora and fauna, partly due to the great range of altitudes, particularly birdlife. The montane forest is protected by the 330 km (130 sq mi) Basilé National Park and

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1562-553: Is 2,009 m (6,591 ft) high, on the southeast of the island. The summit is cut by a small lake-filled caldera , and there is a crater lake on the NE flank. San Joaquin has been active during the last 2,000 years. The southwestern side of Bioko is rainy for most of the year, with annual rainfall in some locations of 10,000 mm (394 in). The climate is tropical at lower altitudes, becoming about 1 °C (1.8 °F) cooler for each 150 m (492 ft) of elevation. There

1633-546: Is 2,260 m (7,410 ft) high with a broad summit caldera, lying at the extreme SW of the island. The volcano dates from the Holocene age and has been active within the last 2000 years. Santa Isabel is the largest volcano at 3,007 m (9,865 ft) in height, and contains many satellite cinder cones. Three eruptions have been reported from vents on the southeast flank during the late-19th and early-20th centuries. San Joaquin , also known as Pico Biao or Pico do Moka,

1704-520: Is 854 km (330 sq mi) in area, lying almost on the equator. The entire island is a massive shield volcano which rises from the floor of the Atlantic Ocean , over 3,000 m (10,000 ft) below sea level, and reaches 2,024 m (6,640 ft) above sea level in the Pico de São Tomé . The oldest rock on São Tomé is 13 million years old. Most of the lava that has erupted over

1775-531: Is an aulacogen , an abandoned arm of a three-armed radial rift system. The other two arms continued to spread during the break-up of Gondwana , as South America separated from Africa. During the Santonian age, around 84 million years ago, the Benue Trough underwent intense compression and folding. Since then it has been tectonically quiet. The basaltic rocks in the oceanic and continental sectors of

1846-582: Is an extinct volcano that rises from deep water to 598 m (1,962 ft) above sea level. The island belongs to Equatorial Guinea . The average temperature is 26.1 °C (79.0 °F), with little seasonal variation. Most rain falls from November to May, with annual precipitation averaging 1,196 mm (47.1 in) - less than on the mainland. Annobón has lush valleys and steep mountains, covered with rich woods and luxuriant vegetation. The small population lives in one community, practicing some agriculture but mainly living by fishing. São Tomé island

1917-418: Is one with a cosmopolitan distribution , having a global or widespread range. A rare alternative term for a species that is endemic is "precinctive", which applies to species (and other taxonomic levels) that are restricted to a defined geographical area. Other terms that sometimes are used interchangeably, but less often, include autochthonal, autochthonic, and indigenous; however, these terms do not reflect

1988-434: Is only possible where 1.) the taxonomy of the species in question is not in dispute; 2.) the species distribution is accurately known; and 3.) the species have relatively small distributional ranges. In a 2000 article, Myers et al . used the standard of having more than 0.5% of the world's plant species being endemic to the region to designate 25 geographical areas of the world as biodiversity hotspots . In response to

2059-415: Is predicted by that hypothesis, and that a source in a lithospheric fracture is more likely to be the explanation. One explanation for the origin of the volcanic line is likely leakage of magma from reactivated Precambrian faults, while another scenario is the rising of mantle material from African Large low-shear-velocity provinces travels under Congo Craton and through existing fractures ultimately feed

2130-422: Is that the similarities are caused by shallow contamination of the oceanic section, which could be caused by sediments from the continent or by rafted crustal blocks that were trapped in the oceanic lithosphere during the separation between South America and Africa. According to some geologists, there is evidence that a mantle plume has existed in the region for about 140 million years, first remaining in roughly

2201-618: Is the sole surviving representative of a formerly diverse group. The concept of phylogenetic endemism has also been used to measure the relative uniqueness of the species endemic to an area. In measurements that incorporate phylogenetic endemism, branches of the evolutionary tree are weighted by how narrowly they are distributed. This captures not only the total number of taxa endemic to the area (taxonomic endemism), but also how distant those species are from their living relatives. Schizoendemics, apoendemics and patroendemics can all be classified as types of neoendemics. Schizoendemics arise from

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2272-555: The Bamboutos Mountains , Mount Oku , and Mount Kupe . Crater lakes dot the plateau, the result of dead volcanoes filling with water. This includes Lake Barombi Mbo and Lake Bermin , which have the highest number of endemic fish species per area recorded anywhere in the world. The 4,095 m (13,435 ft) Mount Cameroon on the coastline, which may have been observed by the Carthaginian Hanno

2343-544: The Cape sugarbird is found exclusively in southwestern South Africa and is therefore said to be endemic to that particular part of the world. An endemic species can also be referred to as an endemism or, in scientific literature, as an endemite . Similarly many species found in the Western ghats of India are examples of endemism. Endemism is an important concept in conservation biology for measuring biodiversity in

2414-1076: The Galápagos Islands and Socotra . Populations on an island are isolated, with little opportunity to interbreed with outside populations, which eventually causes reproductive isolation and separation into different species. Darwin's finches in the Galápagos archipelago are examples of species endemic to islands. Similarly, isolated mountainous regions like the Ethiopian Highlands , or large bodies of water far from other lakes, like Lake Baikal , can also have high rates of endemism. Endemism can also be created in areas which act as refuges for species during times of climate change like ice ages . These changes may have caused species to become repeatedly restricted to regions with unusually stable climate conditions, leading to high concentrations of endemic species in areas resistant to climate fluctuations. Endemic species that used to exist in

2485-703: The West Province is 20 °C (68 °F). Toward the north, rainfall levels are reduced as the Sudan climate becomes predominant. The Western High Plateau's relief and high rainfall make it a major watershed for Cameroon. Important rivers in the region include the Manyu , which rises in the Bamboutos Mountains and becomes the Cross River on its lower course, and the Nkam , which is known as

2556-545: The Wouri River on its lower course. The region gives rise to important tributaries to the Sanaga River . These rivers have a long high-water period during the wet season and a short low-water period during the dry season. Volcanism has created fertile black and brown soils. The Western High Plateau was once heavily forested. However, repeated cutting and burning by humans has forced the forest back to areas along

2627-504: The cougar is endemic to the Americas, and all known life is endemic to Earth. However, endemism is normally used only when a species has a relatively small or restricted range. This usage of "endemic" contrasts with "cosmopolitan." Endemics are not necessarily rare; some might be common where they occur. Likewise, not all rare species are endemics; some may have a large range but be rare throughout this range. The evolutionary history of

2698-430: The 510 km (200 sq mi) Luba Crater Scientific Reserve . There has been little habitat loss, and the southern slopes have remained almost completely undisturbed. Although hunting pressure is rising, the fauna in the inaccessible southern part of the island is mostly intact. This includes an endemic subspecies of drill, Mandrillus leucophaeus poensis . Bioko is a part of Equatorial Guinea . The island has

2769-960: The Balkan Peninsula, Turkey, Alps, Cuba, New Caledonia, South Africa, Zimbabwe, the North American Appalachians, and scattered distribution in California, Oregon, and Washington and elsewhere. For example, Mayer and Soltis considered the widespread subspecies Streptanthus glandulosus subsp. glandulosus which grows on normal soils, to be a paleoendemic, whereas closely related endemic forms of S. glandulosus occurring on serpentine soil patches are neoendemics which recently evolved from subsp. glandulosus . Obligate cave-dwelling species, known as troglobites, are often endemic to small areas, even to single individual caves, because cave habitats are by nature restricted, isolated, and fragmented. A high level of adaptation to

2840-497: The Cameroon line are similar in composition, although the more evolved rocks are quite distinct. The similarity in basaltic rocks may indicate they have the same source. Since the lithosphere mantle below Africa must be different in chemical and isotopic composition from the younger lithosphere below the Atlantic, one explanation is that the source is in the asthenosphere rather than in metasomatized lithosphere. A different view

2911-644: The Cameroon volcanic line. All definitions include the islands and the continental stretch up to Oku. Based on similarities in age and composition, some also include the Ngaoundere Plateau , which extends the line to the east in the Adamawa Plateau ; the Biu plateau of Nigeria to the north of the Yola arm of the Benue Trough, and the Jos Plateau to the west of the Benue Trough. There are varying theories for

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2982-571: The East African Rift Lakes have diversified into many more endemic species than the other fish families in the same lakes, possibly due to such factors. Plants that become endemic on isolated islands are often those which have a high rate of dispersal and are able to reach such islands by being dispersed by birds. While birds are less likely to be endemic to a region based on their ability to disperse via flight, there are over 2,500 species which are considered endemic, meaning that

3053-583: The Foumban Shear Zone can be identified with the Pernambuco fault in Brazil. A major earthquake in 1986 could indicate that the shear zone is reactivating. The Benue Trough lies to the west of the Cameroon line. The Benue Trough was formed by rifting of the central West African basement, beginning at the start of the Cretaceous era. A common explanation of the trough's formation is that it

3124-456: The Gulf of Guinea, the Cameroon line consists of six offshore volcanic swells that have formed islands or seamounts . From the southwest to the northeast the island groups are Annobón (or Pagalu), São Tomé , Príncipe and Bioko . Two large seamounts lie between São Tomé and Príncipe, and between Príncipe and Bioko. On the mainland, the line starts with Mount Cameroon and extends northeast in

3195-584: The Navigator in the 5th century BC, erupted in 2000. Further inland, the stratovolcano Mount Oku at 3,011 metres (9,879 ft) is the second highest mountain in sub-Saharan mainland West Africa . In 1986, Lake Nyos , a crater lake in the Oku volcanic plain , released a cloud of carbon dioxide gas that killed at least 1,200 people. The region has cool temperatures, heavy rainfall, and savanna vegetation. The plateau experiences an equatorial climate with

3266-592: The Western Highlands or the Bamenda Grassfields, continues the Cameroon line into the mainland of Cameroon. The plateau rises in steps from the west. To the east, it terminates in mountains that range in height from 1,000 m (3,300 ft) to 2,500 metres (8,200 ft). The plateau gives way to the Adamawa Plateau to the northeast, a larger but less rugged region. The Western High Plateau features several dormant volcanoes , including

3337-546: The above, the World Wildlife Fund has split the world into a few hundred geographical ' ecoregions '. These have been designed to include as many species as possible that only occur in a single ecoregion, and these species are thus 'endemics' to these ecoregions. Since plenty of these ecoregions have a high prevalence of endemics existing within them, many National Parks have been formed around or within them to further promote conservation. The Caparaó National Park

3408-405: The coast of Cameroon , on the continental shelf. The island used to be the end of a peninsula attached to the mainland, but was cut off when sea levels rose 10,000 years ago at the end of the last last glaciation . With an area of 2,017 km (779 sq mi) it is the largest island in the Cameroon line. Bioko has three basaltic shield volcanoes, joining at the lower levels. San Carlos

3479-583: The concept. In their view, everything is endemic, even cosmopolitan species are endemic to Earth, and earlier definitions restricting endemics to specific locations are wrong. Thus the subdivisions neoendemics and paleoendemics are without merit regarding the study of distributions, because these concepts consider that an endemic has a distribution limited to one place. Instead, they propose four different categories: holoendemics, euryendemics, stenoendemics and rhoendemics. In their scheme cryptoendemics and euendemics are further subdivisions of rhoendemics. In their view,

3550-518: The concepts of neoendemics and paleoendemics in 1965 to describe the endemics of California. Endemic taxa can also be classified into autochthonous, allochthonous, taxonomic relicts and biogeographic relicts. Paleoendemism refers to species that were formerly widespread but are now restricted to a smaller area. Neoendemism refers to species that have recently arisen, such as through divergence and reproductive isolation or through hybridization and polyploidy in plants, and have not dispersed beyond

3621-609: The cool climates of mountain peaks are geographically isolated. For example, in the Alpes-Maritimes department of France, Saxifraga florulenta is an endemic plant that may have evolved in the Late Miocene and could have once been widespread across the Mediterranean Basin . Volcanoes also tend to harbor a number of endemic species. Plants on volcanoes tend to fill a specialized ecological niche , with

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3692-485: The island has been deeply eroded apart from spectacular towers of phonolite . The island is surrounded by smaller islands including Ilheu Bom Bom , Ilhéu Caroço , Tinhosa Grande and Tinhosa Pequena , and lies in ocean 3,000 m (9,800 ft) deep. It rises in the south to 946 m (3,104 ft) at Pico de Príncipe , in a thickly forested area within the Obo National Park. The north and centre of

3763-425: The island were formerly plantations but have largely reverted to forest. As with São Tomé, the island has always been isolated from the mainland and therefore has many unique species of plants and animals, including six endemic birds. Príncipe has a population of around 5,000 people. Other than Portuguese , some speak Principense or Lunguyê with a few Forro speakers. Bioko is just 32 km (20 mi) off

3834-426: The last million years has been basalt . The youngest dated rock on the island is about 100,000 years old, but numerous more recent cinder cones are found on the southeast side of the island. Due to the prevailing southwesterly winds, there is great variability in rainfall. In the rain shadow to the northeast of São Tomé the vegetation is dry savannah, with only 60 cm (24 in) of rain each year. By contrast,

3905-495: The later development of the Cameroon Line around 30 Ma is that it coincides with development of a shallow mantle convection system centered on the mantle plume, and is related to thinning and extension of the crust along the Cameroon line as pressures relaxed in the now stationary plate. The traditional mantle plume hypothesis is disputed by scientists who point out that features of the region are quite different from what

3976-760: The lush south and west of the island receive about 6 m (20 ft) of rain, mostly falling in March and April. The climate is hot and humid with the rainy season from October to May. The higher slopes of the island are forested and form part of the Obo National Park. São Tomé has never been connected to Africa, and therefore has many unique plants and birds. Of the bird species, 16 are endemic and six are near endemic, of which four are only shared with Príncipe. Six species are considered vulnerable , and three are critically endangered (the São Tomé ibis , São Tomé fiscal and São Tomé grosbeak ). Schistometopum thomense ,

4047-407: The north and east coasts, with the chief exports being cocoa , coffee , copra , and palm products. There are large reserves of oil in the ocean between Nigeria and São Tomé which have not yet been exploited. Príncipe is the smaller of the two major islands of São Tomé and Príncipe , with an area of 136 km (53 sq mi). Volcanic activity stopped around 15.7 million years ago, and

4118-677: The pool remains isolated. Other areas very similar to the Galapagos Islands of the Pacific Ocean exist and foster high rates of endemism. The Socotra Archipelago of Yemen, located in the Indian Ocean, has seen a new endemic species of parasitic leech, Myxobdella socotrensis, appear. This species is restricted to freshwater springs, where it may attach to and feed upon native crabs. Mountains can be seen as ' sky islands ': refugia of endemics because species that live in

4189-404: The presence of endemic species in an area is a good method to find geographical regions that can be considered priorities for conservation. Endemism can thus be studied as a proxy for measuring biodiversity of a region. The concept of finding endemic species that occur in the same region to designate 'endemism hotspots' was first proposed by Paul Müller in a 1973 book. According to him, this

4260-545: The same position while the African plate rotated above it, and then remaining stationary under the Oku area since around 66 million years ago. In this theory, the abnormal heat rising in a mantle plume would lead to melting of the upper mantle , which raises, thins and weakens the crust and facilitates rifting. This may have been repeated several times in the Benue Trough between 140 Ma and 49 Ma. One plume-related hypothesis for

4331-462: The shear zone, and may be associated with the Cameroon line. 3°30′0″N 8°42′0″E  /  3.50000°N 8.70000°E  / 3.50000; 8.70000 Endemism 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 found elsewhere. For example,

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4402-669: The similarities between the oceanic and continental volcanoes. The Cameroon line bisects the angle where the coast of Africa makes a 90° bend from the southern coast along the west of the Congo craton and the western coast along the south of the West African craton . The coastline roughly corresponds to the coast of the Borborema geological province of northeastern Brazil, which began to separate from this part Africa around 115 million years ago. The Central African Shear Zone (CASZ),

4473-484: The species is restricted to an area less than five million hectares (twelve million acres). Microorganisms were traditionally not believed to form endemics. The hypothesis 'everything is everywhere', first stated in Dutch by Lourens G.M. Baas Becking in 1934, describes the theory that the distribution of organisms smaller than 2 mm is cosmopolitan where habitats occur that support their growth. Endemism can reflect

4544-464: The status of a species that specifically belongs only to a determined place. The word endemic is from Neo-Latin endēmicus , from Greek ἔνδημος, éndēmos , "native". Endēmos is formed of en meaning "in", and dēmos meaning "the people". The word entered the English language as a loan word from French endémique , and originally seems to have been used in the sense of diseases that occur at

4615-424: The term 'aneuendemics' in 1991 for species that have more or fewer chromosomes than their relatives due to aneuploidy . Pseudoendemics are taxa that have possibly recently evolved from a mutation. Holoendemics is a concept introduced by Richardson in 1978 to describe taxa that have remained endemic to a restricted distribution for a very long time. In a 2000 paper, Myers and de Grave further attempted to redefine

4686-572: The threatened nature of a geographic region. A similar pattern had been found regarding mammals, Lasioglossum bees, Plusiinae moths, and swallowtail butterflies in North America: these different groups of taxa did not correlate geographically with each other regarding endemism and species richness. Especially using mammals as flagship species proved to be a poor system of identifying and protecting areas of high invertebrate biodiversity. In response to this, other scientists again defended

4757-409: The upper slopes where foodcrop cultivation is uneconomical. 5°40′00″N 10°03′00″E  /  5.66667°N 10.05000°E  / 5.66667; 10.05000 Cameroon Volcanic Line The Cameroon volcanic line is geologically unusual in extending through both the ocean and the continental crust. Various hypotheses have been advanced by different geologists to explain the line. In

4828-600: The volcanic activities. The puzzling feature, that the composition of the magmas is the same both in the land volcanoes and the oceanic ones is likely explained by recent studies that show the underlying lithosphere is the same. A gravity study of the southern part of the Adamawa plateau has shown a belt of dense rocks at an average depth of 8 km running parallel to the Foumban shear zone. The material appears to be an igneous intrusion that may have accompanied reactivation of

4899-461: The waterways and has allowed grasslands to expand into the area. Sudan savanna forms the dominant vegetation. This consists of grassfields—leading to the name Bamenda grassfields around the city of Bamenda —and short shrubs and trees that shed their foliage during the dry season as a defence against brush fires and dry weather. Raffia palms grow in the valleys and depressions. Geologists disagree over which volcanic regions should be included in

4970-513: Was formed in the Atlantic Forest , a biodiversity hotspot located in Brazil, in order to help protect valuable and vulnerable species. Other scientists have argued that endemism is not an appropriate measure of biodiversity, because the levels of threat or biodiversity are not actually correlated to areas of high endemism. When using bird species as an example, it was found that only 2.5% of biodiversity hotspots correlate with endemism and

5041-509: Was uncomfortable with the fact that the word ' endemic ' is often associated with diseases. 'Precinctive' was first used in botany by Vaughan MacCaughey in Hawaii in 1917. A species is considered to be endemic to the area where it is found naturally, to the exclusion of other areas; presence in captivity or botanical gardens does not disqualify a species from being endemic. In theory, the term "endemic" could be applied on any scale; for example,

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