The Madagascar ericoid thickets is a

montane shrubland Montane ecosystems are found on the slopes of mountains. The alpine climate in these regions strongly affects the ecosystem because temperatures fall as elevation increases, causing the ecosystem to stratify. This stratification is a crucial f ...

ecoregion An ecoregion (ecological region) or ecozone (ecological zone) is an ecologically and geographically defined area that is smaller than a bioregion, which in turn is smaller than a biogeographic realm. Ecoregions cover relatively large areas of l ...

, found at higher altitudes on

Madagascar Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Africa ...

's four major mountains.

Geography

The ecoregion covers the area above 1800 m elevation on (from north to south)

Tsaratanana ''For other localities with the same name, see Tsaratanana (disambiguation)'' Tsaratanana is a town and commune ( mg, kaominina) in Madagascar. It belongs to the district of Tsaratanana, which is a part of Betsiboka Region. The population of the ...

(2,876 m),

Marojejy Marojejy National Park () is a national park in the Sava region of northeastern Madagascar. It covers and is centered on the Marojejy Massif, a mountain chain that rises to an elevation of . Access to the area around the massif was restricted ...

(2,133 m),

Ankaratra Ankaratra is a cinder cone volcano range located about southwest of Antananarivo, the capital city of Madagascar. It lies between the towns of Arivonimamo to the north, Ambatolampy to the east, Faratsiho to the west and Betafo to the south. It is ...

(2,643 m), and

Andringitra Massif The Andringitra Massif ("desert of rocks") is a granite massif located within Andringitra National Park in Madagascar. The range is approximately long. In its central area, the range is almost wide, though it is much narrower on either end. Pic ...

(2,658 m). The ericoid thickets are surrounded at lower elevations by the

Madagascar subhumid forests The Madagascar subhumid forests are a tropical moist broadleaf forest ecoregion that covers most of the Central Highlands of the island of Madagascar. They are included in the WWF's Global 200 list of outstanding ecoregions. Most of the origin ...

ecoregion. The total area of the ecoregion is . On Tsaratanana the thickets are higher up, starting above 2,500m. There are smaller areas of thicket in Anjanaharibe-Sud Special Reserve in the north and

Andohahela National Park Andohahela National Park, in south-east Madagascar, is remarkable for the extremes of habitats that are represented within it. The park covers of the Anosy mountain range, the southernmost spur of the Malagasy Highlands and contains the last hum ...

to the south.

Flora

The main plant community is thickets. The thickets are composed of evergreen woody shrubs and low trees, which form a single, often impenetrable stratum never more than 6 meters tall. The shrubs and trees typically have an ericoid habit, with short, twisted stems and ericoid, cupressoid, or myrtilloid leaves.White, Frank F. (1983). ''The vegetation of Africa: A descriptive memoir to accompany the Unesco/AETFAT/UNSO vegetation map of Africa''. UNESCO, 1983. ISBN 92-3-101955-4 Characteristic shrubs of the ericoid thickets are from the plant families

Asteraceae The family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the order Asterales. Commonly referred to as the aster, daisy, composite, or sunflower family, Compositae w ...

(species of ''

Psiadia ''Psiadia'', commonly known as daisy trees, is a genus of mostly woody Asian and African plants in the tribe Astereae within the family Asteraceae. The genus is distributed throughout the Western Indian Ocean, with species reported from continen ...

Helichrysum The genus ''Helichrysum'' consists of an estimated 600 species of flowering plants in the sunflower family (Asteraceae). The type species is ''Helichrysum orientale''. They often go by the names everlasting, immortelle, and strawflower. The name ...

, Stoebe'', and '' Stenocline''),

Ericaceae The Ericaceae are a family of flowering plants, commonly known as the heath or heather family, found most commonly in acidic and infertile growing conditions. The family is large, with c.4250 known species spread across 124 genera, making it th ...

(species of ''

Erica Erica or ERICA may refer to: * Erica (given name) * ''Erica'' (plant), a flowering plant genus * Erica (chatbot), a service of Bank of America * ''Erica'' (video game), a 2019 FMV video game * ''Erica'' (spider), a jumping spider genus * Eric ...

, Agauria'', and ''

Vaccinium ''Vaccinium'' is a common and widespread genus of shrubs or dwarf shrubs in the heath family (Ericaceae). The fruits of many species are eaten by humans and some are of commercial importance, including the cranberry, blueberry, bilberry (whort ...

''),

Rhamnaceae The Rhamnaceae are a large family of flowering plants, mostly trees, shrubs, and some vines, commonly called the buckthorn family. Rhamnaceae is included in the order Rosales. The family contains about 55 genera and 950 species. The Rhamnaceae h ...

(''

Phylica ''Phylica'' is a genus of plants in the family Rhamnaceae. It contains about 150 species, the majority of which are restricted to South Africa, where they form part of the '. A few species occur in other parts of southern Africa, and on islands ...

''), and

Rubiaceae The Rubiaceae are a family of flowering plants, commonly known as the coffee, madder, or bedstraw family. It consists of terrestrial trees, shrubs, lianas, or herbs that are recognizable by simple, opposite leaves with interpetiolar stipules ...

. Low trees, widely-spaced, rise a little higher than the shrub canopy. Native trees include '' Agauria salicifolia,

Ilex mitis ''Ilex mitis'' (commonly called Cape holly, African holly, waterboom or umDuma) is a tall, dense, evergreen tree that is indigenous to Sub-Saharan Africa and Madagascar. It makes an excellent fast-growing hedge for gardens - growing tall, stra ...

, Neocussonia bojeri,

Razafimandimbisonia minor ''Razafimandimbisonia'' is a genus of flowering plants in the family Rubiaceae. It is endemic to Madagascar. Taxonomy The genus ''Alberta'' was shown to be paraphyletic in a phylogenetic analysis of the tribe Alberteae. The type species ''Albe ...

, Dodonaea madagascariensis,

Tambourissa gracilis ''Tambourissa'' is a genus of plant in family Monimiaceae. Its range includes Madagascar, the Comoro Islands, Réunion, and Mauritius. It contains the following accepted species, according to ThePlantList.org: * '' Tambourissa alaticarpa'' Loren ...

, Podocarpus rostratus, Vitex humbertii, Faurea forficuliflora,

Pittosporum ''Pittosporum'' ( or ) is a genus of about 200 species of flowering plants in the family Pittosporaceae. The genus is probably Gondwanan in origin; its present range extends from Australasia, Oceania, eastern Asia and some parts of Africa. '' Ci ...

'' sp., and several species of ''

Weinmannia ''Weinmannia'' is a genus of trees and shrubs in the family Cunoniaceae. It is the largest genus of the family with about 150 species. It is also the most widespread genus, occurring in Central and South America including the Caribbean, Madagasc ...

''. Other plants include the arborescent monocots ''

Dracaena reflexa ''Dracaena reflexa'' (commonly called song of India or song of Jamaica) is a tree native to Mozambique, Madagascar, Mauritius, and other nearby islands of the Indian Ocean. It is widely grown as an ornamental plant and houseplant, valued for its ...

'' and '' Pandanus alpestris''.

Lichen A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.Impatiens ''Impatiens'' is a genus of more than 1,000 species of flowering plants, widely distributed throughout the Northern Hemisphere and the tropics. Together with the genus ''Hydrocera'' (one species), ''Impatiens'' make up the family Balsaminaceae. ...

'' inhabit the ground layer.

Epiphytic An epiphyte is an organism that grows on the surface of a 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 epiphytes grow are called phoroph ...

mosses and lichens, along with a few small orchids, grow plentifully on the branches of shrubs and trees. The thickets are home a large number of endemic plants, many of whose closest relatives live in

South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring countri ...

and the highlands of

East Africa East Africa, Eastern Africa, or East of Africa, is the eastern subregion of the African continent. In the United Nations Statistics Division scheme of geographic regions, 10-11-(16*) territories make up Eastern Africa: Due to the historical ...

. Andringitra alone is home to 150 vascular endemics, including 25 species of

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. Along with the Asteraceae, they are one of the two largest families of flowering ...

. The palm ''

Dypsis acuminum ''Dypsis'' is a genus of flowering plants in the family Arecaceae. They are slender, evergreen palms with yellow flowers carried in panicles amongst the pinnate leaves. Many ''Dypsis'' species have aerial branching (above the main trunk), a rare ...

'' is endemic to the Manongarivo Massif. In much of the ecoregion, secondary grassland, established by regular livestock grazing and burning, has almost entirely replaced the original thicket vegetation. The most common grasses on Ankaratra's secondary grasslands are '' Pentameris natalensis, P. humbertii, Andropogon trichozygus, Anthoxanthum madagascariense, Digitaria ankaratrensis,

Agrostis elliotii ''Agrostis'' (bent or bentgrass) is a large and very nearly cosmopolitan genus of plants in the grass family, found in nearly all the countries in the world. It has been bred as a GMO A genetically modified organism (GMO) is any organism ...

Merxmuellera macowanii ''Merxmuellera'' is a genus of African grasses named for Hermann Merxmueller, a 20th century German botanist and taxonomist who was an expert on African flora. Species ''Merxmuellera'' contains the following species: * '' Merxmuellera ambalavao ...

, Brachypodium perrieri, Poa madecassa, P. ankaratrensis'', and '' Festuca camusiana''. Secondary grassland species are also found in mountain bogs.

Fauna

These high points of Madagascar are home to less diverse animal life than on the lower slopes, but with a high proportion of endemics. The area was not thoroughly researched until the 1990s. There are at least ten species of endemic and near-endemic reptiles including the dwarf gecko '' Lygodactylus arnoulti''.

Threats and preservation

The thickets are vulnerable to fire, and many have been converted to cattle pasture. The widespread conversion of thickets to secondary grasslands may be relatively recent. In 1777 Ankaratra was reported covered with forest. Until the end of the 19th century Andringitra's thickets were a refuge from trouble for local people and their flocks. Ankaratra's and Andringitra's thickets were mostly converted to pasture in the 20th century. Andringitra, Tsaratanana, and Marojejy are all protected areas, and Andringitra's thickets have partially recovered since it was protected. 32.1% of the ecoregion is in protected areas. Protected areas include

Marojejy National Park Marojejy National Park () is a national park in the Sava region of northeastern Madagascar. It covers and is centered on the Marojejy Massif, a mountain chain that rises to an elevation of . Access to the area around the massif was restricted ...

, Tsaratanana Strict Nature Reserve,

Andringitra National Park Andringitra National Park is a national park in the Haute Matsiatra region of Madagascar, south of Ambalavao. The park was established in 1999 and is managed by the Madagascar National Parks Association. It was inscribed in the World Heritage Sit ...

, and

Rainforests of the Atsinanana The Rainforests of the Atsinanana is a World Heritage Site that was inscribed in 2007 and consists of 13 specific areas in six national parks in the eastern part of Madagascar: # Marojejy National Park # Masoala National Park # Zahamena National ...

World Heritage Site A World Heritage Site is a landmark or area with legal protection by an international convention administered by the United Nations Educational, Scientific and Cultural Organization (UNESCO). World Heritage Sites are designated by UNESCO for h ...

References

External links