Madagascar subhumid forests

Content Cover Image

Madagascar. Source: WWF/ Oliver Langrand

The Madagascar subhumid forests ecoregion, covering most of the Central Highlands of Madagascar, boasts a considerable number of endemic species, found chiefly in the relict forest patches and also in some wetland areas, but the remaining habitats are agricultural areas that have almost no biological value, or eroded bare soil areas virtually devoid of vegetation.

This ecoregion is the site of some of the major extinctions of recent times, including that of the world’s largest flightless bird, Madagascar elephant bird (Aepyornis maximus); this bird stood at a height of three metres and attained a body mass of one fourth of a ton. It was hunted to extinction by native peoples, who also collected the eggs for human consumption. A number of large lemurs have also been driven to extinction by native people's activities, primarily due to slash-and-burn shifting agricultural practises. With only small fragmented areas of habitat left within this ecoregion, there is a high risk of further species extinction over the next several decades. The Madagascar subhumid forests is classified within the Tropical and Subtropical Moist Broadleaf Forests biome.


Location and general description

The Madagascar subhumid forests are scattered in several biological islands of montane humid forest throughout the  Central Highlands of Madagascar, the zone generally defined as above the coastal plain and escarpment contour line at 900 metres. The remaining substantial areas of forest habitat are in the Sambirano region in the northwest, portions of Amber Mountain (Montagne d’Ambre) in the north, significant areas of the northern highlands, and the middle elevational portions of certain massifs in the Central Highlands (e.g., Ankaratra and Andringitra). Also included are some wetlands and lakes (e.g., Lake Alaotra) and the "tapia" forest of the Central Highlands between 800-1600 m and in the dry southwest portion of the ecoregion. Also, a few remnant regions of forest, isolated and highly fragmented, remain scattered across the central highlands (e.g., Ambohitantely, Ambohijanahary, Isalo). In the extreme southwest of the island, the isolated mountain of Analavelona retains in the disjunctive summital area (1000-1300 m) a remnant subhumid forest surrounded by much drier vegetation. Degraded forests, huge expanses of secondary grasslands and exotic tree plantations surround these habitats. This secondary vegetation is the result of human activity; forest clearing and exploitation.

The subhumid forest ecoregion has been previously mapped as part of the eastern Madagascar regional center of endemism. To the east, these subhumid forests meet moist forests, in the lowland forest ecoregion around 800 m elevation, and to the west they merge into the dry deciduous forest ecoregion around 600 m elevation. At higher elevations (generally above 1800 to 2000 m) these habitats are replaced by ericoid thickets.

caption Source: World Wildlife Fund

The rainfall is approximately 1500 mm per year, although it may amount to as much as 2000 mm in the Sambirano area in the northwest and as little as 600 mm in the southwest. The temperatures at higher elevations are mainly moderate, between 15° and 25°C. There is a cool, dry season between July and September and a warmer wet season during the rest of the year.


Vast grasslands now cover much of the central highlands at elevations ranging from 1000 to 1500 metres. The majority of this upland area was formerly forested, and native peoples have affected the fauna and flora through massive deforestation. It is clear there have been very significant anthropogenic (human-caused) changes in the ecoregion. The central highlands was once home to a remarkable array of endemic species. These included several species of elephant birds (Aepyornithidae), including the world’s largest bird species (Aepyornis maximus), a giant tortoise, and several species of lemurs most of which were large bodied primates, some more massive than female gorillas, for example. All of these species have become extinct since the arrival of humans on the island approximately 2000 years ago.



There are few remaining patches of subhumid forest on the central highlands. Small patches are found on Ankaratra Massif, and some larger forest blocks are on the slopes of Andringitra and Tsaratanana massifs. At the higher elevations, the subhumid forest, also referred to as sclerophyllous montane forest, holds canopy trees that are ten to twelve metres in height, including species from the families Rubiaceae, Lauraceae, Verbenaceae and Ericaceae. At lower elevations, from 1400 to 1600 m, the forest has a fifteen metre high canopy and includes species in the families Cunoniaceae, Araliaceae, Cornaceae, Celestraceae, Anacardiaceae, Burseraceae, Euphorbiaceae, Lauraceae and Ebenaceae.

Amber Mountain (Montagne D’Ambre) contains a significant area of humid forest. An isolated basaltic mountain with a humid microclimate above 1000 m, it is surrounded by dry deciduous forests. At sea level, the annual precipitation is approximately 980 mm, while at the peak of Amber Mountain the precipitation averages 2378 mm. The humid forest on the mountain slopes has a canopy forty metres high, dominated by plants from the families Sapotaceae, Burseraceae, Monimiaceae, Lauraceae, Flacourtiaceae, Sterculiaceae, Myrtaceae, Annonaceae, Apocynaceae, Potaliaceae and Elaeocarpaceae. In addition to the floral diversity of the forest, the faunal diversity is high with eight species of primates and nearly 80 species of birds, including the endemic Ambre Mountain Rock Thrush (Monticola erythronotus). As the natural habitats of this ecoregion experienced numerous vegetational shifts associated with Pleistocene climatic vicissitudes, many species are endemic and have very narrow altitudinal or isolated distributions.


Biodiversity features

caption Vasa parrot (Coracopis sp.), Madagascar. Source: WWF

This ecoregion is similar to others in Madagascar in that most natural vegetation cover has been destroyed. The remaining small and isolated patches or distinctly larger blocks are biodiversity "jewels" essential for a variety endemic species. There are a total of 495 vertebrate species recorded in the Madagascar subhumid forests.


Numerous mammalian taxa are strictly endemic to this ecoregion, including the Alaotran gentle lemur (Hapalemur griseus aloatrensis), and numerous shrews, tenrecs and rodents. A far larger number of species are near endemic, with the majority of these shared with the lowland forests to the east. At least 45 species of mammals are found only in the subhumid forest ecoregion and the lowland forest ecoregion of Madagascar and these include, for example, two species of bamboo lemurs (Hapalemur aureus and H. simus).

caption Diademed sifaka, Montadia. Source: C.Michael Hogan Of the endemic and near-endemic mammal species in the ecoregion, 12 species listed are on the IUCN Red List; nine species are considered vulnerable; two are endangered and one (the Alaotran gentle lemur) is critical. In the Analavelona forest a species of small mammal was recently discovered, Microgale nasoloi, that is only known from this site and the nearby Zombitse-Vohibasia Forest, the latter being classified in the Madagascar succulent woodlands ecoregion.

In addition to the large number of mammalian endemics, there are many special status mammals in the ecoregion, including the Vulnerable Aquatic tenrec (Limnogale mergulus); and the Near Threatened Aye aye (Daubentonia madagascariensis).




There are at least 25 strictly endemic reptiles in this ecoregion. These numbers include historically described species as well as newly identified taxa. Numerous speciess of chameleon and dwarf chameleon only occur in this ecoregion, including Calumma oshaughnessyi ambreensis, C. tsaratananensis, Furcifer petteri, Brookesia ambreesis, B. antakarana, B. lineata, and B. lolontany in the northern and northwestern portion; and C. fallax, F. campani, and F. minor in the central and southern portions. Otpher lizard species endemic to the ecoregion include the skinks Mabuya grnadidieri, M. madagascariensis, M. nancycoutouae, Amphiglossus meva, and Androngo crenni; the geckos Lygodactylus blanciL. decaryi and Phelsuma klemmeri, and the Plated lizard Zonosaurus ornatus. There are also a few endemic species of snakes including Pseudoxyrhopus ankafinensis, Liopholidophis grandidieri, and L. sexlineatus.


The Madagascar subhumid forests hold more than twenty strictly endemic amphibians. Several groups of amphibians include more than one endemic species, such as the microhylids Rhombophryne testudo, Scaphiophryne goettliebi, the mantellids Vulnerable Elegant Madagascar frog (Spinomantis elegans); Mantella crocea, M. cowani, M. eiselti, Mantidactylus domerguei, and the Near Threatened Decary's Madagascar frog (Gephiyromantis decaryi); and the rhacophorids Boophis laurenti and B. microtympanum. Other notable amphibian endemics include: Benavony stump-toed frog (Stumpffia gimmeli);

There are a number of special status amphibians in the ecoregion including the Near Threatened Ambohimitombo bright-eyed frog (Boophis majori); the Vulnerable Andoany stump-toed frog (Stumpffia pygmaea); the Endangered Andringitra Madagascar Frog (Mantidactylus madecassus); and the Near Threatened Betsileo Bright-eyed Frog (Boophis rhodoscelis).

Ecological status

caption Captive Zebu grazing in secondary forest clearing east of Antananarivo. Source: C.Michael Hogan


Ecological threats

Remaining patches of forest and woodlands of the Central Highlands face continuous and intensive pressure from encroaching agriculture, increasing exploitation by growing human populations, and fire. Alien species of plants and animals are affecting habitat integrity. Nearly all of the ecoregion has been modified either directly or indirectly by humans.

The wetland areas on the central highlands are threatened by conversion to rice farming, siltation, and water pollution. Most marshlands and wetlands of Madagascar have already been degraded or converted to rice cultivation. Relatively undisturbed areas remain, including the marshlands and associated forest of the Torotorofotsy area near Andasibe and other sites scattered throughout the ecoregion. Many of these marshlands suffer water pollution with runoff from surrounding agricultural lands. Extinctions of freshwater fish have occurred in these wetlands in the last few years. Lake Alaotra, in particular, is an important wetland possessing the endemic Alaotra little grebe and Madagascar pochard. The lake is also home to an endemic primate subspecies, the Alaotra gentle lemur (Hapalemur griseus alaotrensis), and several species of endemic fish. Lake Itasy used to be a significant habitat for waterbirds, but has been degraded by intensive rice cultivation.

Justification of ecoregion delineation


Neighbouring ecoregions

The following ecoregions have some tangency to the Madagascar subhumid forests:









Fund, W., & Hogan, C. (2015). Madagascar subhumid forests. Retrieved from http://www.eoearth.org/view/article/51cbee5e7896bb431f697559


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