Thearchipelago comprises three large islands,Mauritius,Réunion, andRodrigues, plus a number of volcanic remnants in the tropics of the southwestern Indian Ocean, generally between 700 and 1,500 kilometres east of Madagascar. Theterrain includes a variety ofreefs,atolls, and small islands. They present varioustopographical andedaphic regions. On the largest islands these gave rise to endemism and unusual biodiversity. Theclimate is oceanic andtropical.
Mauritius is located 900 km east ofMadagascar. It has an area of 1,865 km2. The highest point is 828 meters above sea level. Mauritius is the most populous of the Mascarene Islands,[1] with a population of 1,252,964.
Réunion is located 150 km southwest of Mauritius. It is the largest of the islands, with an area of 2,512 km2.Piton des Neiges (3,069 m), an extinct volcano, is the highest peak on Réunion and in the islands.Piton de la Fournaise is an active volcano on Réunion which erupts frequently.[1]
Rodrigues is located 574 km east of Mauritius. It has an area of 108 km2, and reaches 393 meters elevation.[1]
St. Brandon, also known as theCargados Carajos shoals, is acoral atoll group consisting of a barrier reef, shoals, and low islets. It is the remnant of one -or more- large volcanic islands sitting on theMauritia (microcontinent) which were submerged by rising tides. Today, the thirty or so islands that compriseSt Brandon form part of the Republic ofMauritius. Around seventeen of the uninhabited islands are administered by the 'Outer Islands Development Corporation' of Mauritius (an entity run by the Prime Minister of Mauritius through the Prime Minister's Office) whilst the remaining Thirteen Islands of St. Brandon are managed by theRaphael Fishing Company from three permanently inhabited island bases ofIle Raphael,L'île du Sud (South Island, l'île Boisées) andL'Île Coco. TheRaphael Fishing Company was granted these Thirteen Islands ofSt. Brandon under a 1901 Permanent Lease (999-year lease) which were adjudged as aPermanent Grant by determination of thePrivy Council (United Kingdom) in 2008.[2][3] These Thirteen islands ofSt. Brandon on Permanent Grant areL'île du Sud (South Island, l'île Boisée), Petit Fou, l'Avocaire, l'île aux Fous,L'île du Gouvernement, Petit Mapou, Grand Mapou, La Baleine,L'Île Coco,Île Raphael, Verronge, l'île aux Bois and Baleines Rocks.
Nazareth Bank is located just north of Cargados Carajos, and prehistorically they were a single geological feature. Today it is a large, shallow fishing bank.
The islands arevolcanic in origin;Saya de Malha (35mya) was the first of the Mascarene islands to rise out of the Indian Ocean due to theRéunion hotspot, followed byNazareth Bank (approximately 2 mya later),Soudan Bank andCargados Carajos. The youngest islands to form were Mauritius (7–10 mya), the oldest of the existing islands, created along with the undersea Rodrigues ridge. The islands of Rodrigues and Réunion were created in the last two million years. Réunion is the largest of the islands (2,500 km2), followed by Mauritius (1,900 km2) and Rodrigues (110 km2). Eventually, Saya de Malha, Nazareth and Soudan were completely submerged, Cargados Carajos remaining as a coral atoll.[4] The Réunion hotspot was beginning to cool and Rodrigues came out as a small island.
Réunion is home to the highest peaks in the Mascarenes, theshield volcanoesPiton des Neiges (3,069 m) andPiton de la Fournaise (2,525 m). Piton de la Fournaise, on the southeastern corner of Réunion, is one of the most active volcanoes in the world, erupting last in December 2021.Piton de la Petite Rivière Noire (828 m) is the highest peak on Mauritius, and the gentle hills of Rodrigues rise to only 390 m.
TheMascarene Plateau is an undersea plateau that extends approximately 2000 km, from theSeychelles to Réunion. The plateau covers an area of over 115,000 km2 of shallow water, with depths ranging from 8 to 150 meters, plunging to 4000 m to theabyssal plain at its edges. The southern part of the plateau, including theSaya de Malha Bank,Nazareth Bank,Soudan Banks andCargados Carajos Shoals (Saint Brandon) (then one large island), was formed by the Réunion hotspot. These were once volcanic islands, much like Mauritius and Réunion, which have now sunk or eroded to below sea level or, in the case of the Cargados Carajos, to low coral islands. The Saya de Malha Bank formed 35 million years ago, and the Nazareth Bank and the Cargados Carajos shoals after that.Limestone banks found on the plateau are the remnants ofcoral reefs, indicating that the plateau was a succession of islands. Some of the banks may have been islands as recently as 18,000–6,000 years ago, when sea levels were as much as 130 meters lower during the most recentice age.
The early colonial history of the islands, like that of the Caribbean, featured a succession of takeovers between rival powers: the Portuguese, Dutch, French and British all ruled some or all of the islands.
Around 1507, the explorerDiogo Fernandes Pereira discovered the island group. The area remained under nominal Portuguese rule untilÉtienne de Flacourt arrived with a French naval squadron and took possession in 1649.[5] From 4 June 1735 to 23 March 1746, a single French Mascarene Islands chartered colony under onegouverneur général (governor general) containedIsle de France (nowMauritius),Île Bourbon (Réunion) andSéchelles (Seychelles). On 14 July 1767 this became a French crown colony, still under one governor general. From 3 February 1803 until 2 September 1810 the French colony ofIndes-Orientales, under acapitaine général (captain-general), included Réunion and (nominally) the Seychelles.
It is postulated from navigational charts, such as theCantino planisphere of 1502,[6] that Arab sailors first discovered Mauritius around 975, calling it Dina Arobi (abandoned island).[7][8] The earliest confirmed discovery on record was in 1507 by Portuguese sailors.
Isle de France (Mauritius) under the French
The Dutch took physical possession in 1598, establishing a succession of short-lived settlements over a period of about 120 years, before abandoning their efforts in 1710.France took control in 1715, renaming itIsle de France. In 1810, the United Kingdom invaded the island to protect its East India ships coming around the Cape of Good Hope from French pirates. Four years later, at the Treaty of Paris, France ceded Mauritius and its dependencies to the United Kingdom. UnderBritish Mauritius (1810-1968), the island successfully developed as a sugar cane-based plantation economy and colony until independence in 1968.
Rodrigues was first discovered by theArabs but named after Portuguese navigatorDiogo Rodrigues. It was under Dutch control in 1601 and settled by the French in 1691. Britain took possession of Rodrigues in 1809. When Mauritius gained independence in 1968, Rodrigues was forcefully joined to it.[discuss] Rodrigues remains an autonomous region of Mauritius.[citation needed]
Réunion was discovered first by the Arabs then by the Portuguese, who named it Santa Apolónia. It was then occupied by the French as part of Mauritius. It was first inhabited by French mutineers who arrived on the island between 1646 and 1669.[9] It was given its current name in 1793. From 1810 to 1815 it was held by the British, before being returned to France. Réunion became anoverseas department of France in 1946.[10]
The climate of the islands is tropical. At low elevations summer temperatures (December to April) average 30 °C. Winter temperatures (May to November) are generally cooler, around 25 °C. Temperatures are cooler in the mountains, averaging 18 °C. During the winter short-lived snow can fall on Réunion's high peaks.[11]
Southeasterlytrade winds blow throughout the year. Rainfall is generally higher on the windward sides of the islands. On Mauritius average annual rainfall in the lowlands varies from 1905 mm on the windward southeast coast to 890 mm on the leeward side. Rainfall in the mountains is higher, varying from 2540 mm to 4445 mm annually.Tropical cyclones occur occasionally, bringing heavy rain and high winds, and causing erosion and landslides.[11]
The habitats of the Macarenes vary with the islands' size, topography, age, and proximity to Madagascar, the nearest major land mass. As is common among remote islands, the Mascarene fauna and flora display a high degree ofendemism; they include over a thousand species of which several hundred are endemic. The Mascarene islands form a distinctecoregion known as theMascarene forests.[11] Until Europeans first settled the islands in the sixteenth century the Mascarenes are not known to have harbored any human population, and the islands' wildlife was still flourishing during the early days of settlement. Today much of the natural vegetation is gone, and there are manyintroduced species on the islands.
In prehistoric times the islands were covered in a diverse range oftropical moist broadleaf forests. The plant communities are not homogeneous, and comprise at least five fairly distinct vegetation zones that reflect variations in altitude and in moisture regime. These include dry lowland forests, semi-dry sclerophyllous forests, lowland rainforests, montane cloud forests, and high-elevation heathlands on Réunion.[12]
Coastal habitats include beach vegetation, coastalwetlands, andswamp forests, grading into lowland rain forest on the windward sides of the islands and lowland dry forests to leeward.
The dry lowland forests are found on the leeward sides of the islands, from sea level to 200 metres in areas with less than 1000 mm of average annual rainfall. Palms are the dominant trees, including species ofLatania andDictyosperma album, along with the palm-like screw-pines (Pandanus spp.).[12]
Thecloud forests are evergreen rain forests found on mountain slopes with high rainfall. They occur on Réunion between 800 and 1900 metres elevation on eastern slopes with an average annual rainfall of 2000–10,000 mm, and between 1100 and 2000 metres on western slopes with an average annual rainfall of 2000–3000 mm. By 2005, relatively intact cloud forests still covered approximately 44,000 ha on Réunion. On Mauritius they are restricted to a small area ofMontagne Cocotte in the island's southwest, above 750 metres elevation and with average annual rainfall of 4500–5500 mm. Trees form a dense canopy 6 to 10 metres high. Typical canopy trees include species ofDombeya on Réunion, and species ofMonimia andTambourissa (Monimiaceae) on both islands. There is an understory of small trees and shrubs including species ofPsiadia (Asteraceae) andMelicope (Rutaceae). The forests are rich inepiphytes (orchids, ferns, mosses, lichens), emergenttree ferns (Cyathea species), and, originally the palmsAcanthophoenix rubra, but poaching has wiped out palms in many areas of Réunion. Three monodominant plant communities are also found in the cloud forests – forests ofAcacia heterophylla (Fabaceae) as the canopy tree, which are similar to theAcacia koa forests inHawaii, thickets dominated byErica reunionensis (Ericaceae), and hyperhumid forests of screw-pine (Pandanus montanus).[12]
Most of the indigenous Mascareneflora and fauna are thought to have descended originally fromMadagascan andAfrican ancestors.[12]
The four largest families present in the Mascarene Islands areMyrtaceae,Rubiaceae,Orchidaceae, andEuphorbiaceae, which comprise between 193 and 223 species each, for a total of 831 species, or 26.9% of the flowering plant flora. Another seven families contain 80 or more species each:Poaceae,Apocynaceae,Cyperaceae,Cunoniaceae,Rutaceae,Araliaceae, andSapotaceae, representing an additional ca. 660 species in all, 21.3% of the angiosperm flora.[12] Ferns are prominent components of the biotas of the islands, especially in the tropical forest. Most ferns disperse easily viaornithochory of their spores, allowing fairly frequent colonization from Madagascar and exchange among the Mascarene islands.[13]
There are 24 species of trees and shrubs in the Mascarenes from subfamilyDombeyoideae, 23 of which are endemic to the islands.[15] The Macarenes' endemic species are polyphyletic and split into nine clades.Trochetia appears monophyletic and more closely related toEriolaena andHelmiopsis than toDombeya. AllDombeya taxa are included in a clade together withRuizia andAstiria, this means thatDombeya is paraphyletic. In terms of breeding systems the Malagasy Dombeyoideae arehermaphroditic, whereas those of the Mascarenes are considereddioecious. Thepolyphyly of the Mascarene Dombeyoideae suggests that dioecy has been acquired several times. At least five colonization events from Madagascar to the Mascarene archipelago occurred. The evolutionary history of two lineages of Mascarene Domeyoideae seems to be related to adaption to xeric habitats.[16]
The flora of the islands co-evolved with the island's unique fauna over millions of years. The human-caused extinction of several of the Mascarenes' land animals, and the introduction of exotic animals to the islands by humans, has disrupted the reproduction and thriving of various island plants. For example, theTambalacoque tree (Sideroxylon grandiflorum), often called the dodo tree, is not producing young trees and is threatened with extinction. The extinctdodo,Cylindraspistortoises, andbroad-billed parrots, along withfruit bats, played an important role in dispersing the seeds. Passing through the animals' digestive tract aided in the seeds' germination. However the trees' decline may be mostly due to introducedcrab-eating macaques (Macaca fascicularis) destroying unripened seeds.[12]
Much of the Mascarenes' native fauna has become endangered or extinct since the human settlement of the islands in the 17th century. Settlers cleared most of the forests for agriculture and grazing, and introduced many exotic species, includingpigs,rats,cats,monkeys, andmongooses.[citation needed]
Contemporary sources state that the dodo usedgizzard stones[19] and could swallowOcotea fruits.[19][20] Seed distribution of at least someOcotea species is performed byfrugivorous birds and there exist a few reports of "solitaires" from the Mascarenes without mention of which island these came from, and the term was also used for otherspecies with "solitary" habits, such as theRéunion blue swamphen and theRéunion sacred ibis. At one point it was even believed that Réunion was the home of not only a white dodo, but also a white solitaire.[21] In 1786, sub-fossil bones were discovered in a cave which confirmedLeguat's descriptions, but at this time no living residents of Rodrigues remembered having seen living birds. The starconstellationTurdus Solitarius was named after this bird.[citation needed]
Mauritius, Réunion, and Rodrigues were also once each home to one or more species ofgiant tortoises, now extinct, which comprised the genusCylindraspis. There are 13 living endemic reptile species, including a number of species of daygeckoes (genusPhelsuma).[11]
The three largest islands have many freshwater streams which descend from the mountains to the sea. The upper reaches, particularly on Réunion, are fast-flowing and steep with numerous waterfalls.Tamarin Falls or Sept Cascades (293 m) on Mauritius is the highest waterfall on Mauritius, while CascadeTrou de Fer (725 m, ranks 23rd worldwide) on Réunion is the highest of the Mascarenes.[23]
The Grand River South East (34 km) is the longest river on Mauritius, followed by Rivière du Poste (23 km), Grand River North West (22 km), Rivière La Chaux (22 km), and Rivière des Créoles (20 km). Mauritius has two natural crater lakes, Grand Bassin and Bassin Blanc.[23]
The Mascarene Islands are surrounded by approximately 750 square km of coral reef. Rodrigues has nearly continuousfringing reefs bounding an extensive lagoon, 7 to 20 km wide, with deep channels. Mauritius is also surrounded by a fringing reef.[1] In contrast, Réunion has very short stretches of narrow fringing reef along the western and southwestern coasts only. The islets of the Cargados Carajos Shoals, which have a very depauperate terrestrial biota owing to being so low-lying and swamped during cyclones, are bound to the east by an extensive arc of fringing reef, which accounts for ~30% of the reefs of the Mascarene Islands. Lagoon reefs and reef flats are dominated by scleractinian corals such as branching and tabularAcropora,Porites massives, foliaceousMontipora andPavona, and sand consolidated with beds of seagrass suchHalophila (Hydrocharitaceae).Among coral reef fishes, wrasses (Labridae), damselfish (Pomacentridae), carnivorous groupers (Serranidae), andsurgeonfishes (Acanthuridae) have many species.[12]
The Saint Brandon Conservation Trust at Corporate Council on Africa in May 2024 in Dallas, Texas
Mauritius has one of the highest population densities in the world. All of the islands have experienced significant losses of habitats. Many of the surviving endemic species are still threatened with extinction and have little protection. Less than 40 percent of Réunion is covered with natural vegetation, only about 5 percent of Mauritius, and almost none of Rodrigues. On Réunion, forest has been cleared for agriculture and then overtaken by introduced plants. Mauritius was largely converted to sugar cane, tea, and conifer plantations. On Rodrigues, shifting cultivation has caused the damage.
^Dransfield, John; Uhl, Natalie W.; Asmussen, Conny B.; Baker, William J.; Harley, Madeline M.; Lewis, Carl E. (2008).Genera Palmarum: The Evolution and Classification of Palms. Royal Botanic Gardens, Kew.ISBN978-1-84246-182-2.
^Le Péchon, Timothée; Dai, Qiang; Zhang, Li-Bing; Gao, Xin-Fen; Sauquet, Hervé (2015). "Diversification of Dombeyoideae (Malvaceae) in the Mascarenes: Old Taxa on Young Islands?".International Journal of Plant Sciences.176 (3):211–221.doi:10.1086/679350.S2CID83958986.
^Péchon, Timothée Le; Cao, Nathanaël; Dubuisson, Jean-Yves; Gigord, Luc D.B. (2009). "Systematics of Dombeyoideae (Malvaceae) in the Mascarene archipelago (Indian Ocean) inferred from morphology".Taxon.58 (2):519–531.doi:10.1002/tax.582016.
^UNEP-WCMC (2021). Protected Area Profile for Réunion from the World Database of Protected Areas. Accessed 18 August 2021.[3]Archived 2021-12-20 at theWayback Machine
Diamond, Jared, (1984) "Historic extinctions: A rosetta stone for understanding prehistoric extinctions". In: P. Martin and R. Klein (eds.) (1984)Quaternary Extinctions: A prehistoric revolution. University of Arizona Press,Tucson.
del Cantino, Cantino planisphere image, zoomable to very high resolution, atBibliothèque et Archives nationales du Québec. (Click on1:1 button to get maximum resolution. Click onImage plein écran to get full-screen view.)(in French)
1 1975 is the year of East Timor's Declaration of Independence and subsequentinvasion by Indonesia. In 2002, East Timor's independence was fully recognized.
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