Madagascar is an island state located in the Indian Ocean, SE of the African continent, from which the Mozambique Channel separates it.
According to BAGLIB, the base of the island it consists of very ancient crystalline rocks, dominated by sedimentary formations of the late Paleozoic and Mesozoic, at times covered by vast basaltic expansions deriving from the ascent of magmas through numerous faults present. The central core of the relief is formed by a plateau that reaches altitudes between 1000 and 1500 m in height, characterized by the presence of numerous volcanic systems, especially in the northern region, where the Tsaratanana massif rises (2876 m). The eastern side slopes steeply towards a rather narrow coastal plain, where there are lagoons flanked by long coastal strips. AO, on the other hand, the reliefs slope more gently towards the plains and valleys that open onto the articulated coast of the Mozambique Channel.
In relation to the asymmetrical position that the central watershed of the island occupies, the waterways have a very different regime. It is quite regular for those descending to the east coast, thanks to the frequency and abundance of rainfall, although it is often interrupted by rapids and waterfalls. The rivers on the western side (Betsiboka, Tsiribihina, Mangoki and others), on the other hand, show a more irregular regime (full in summer and lean in winter), are longer and have greater flow.
The climate is characterized by high temperatures, given the position of Madagascar between the parallels of 12 ° and 26 ° S, so that agriculture is allowed in different forms almost everywhere: not even the areas located at the highest altitudes record, in fact, thermal values too low. The climatic differences are mainly related to the distribution of precipitation. The east coast receives large amounts of rain throughout the year, due to the constant rhythm of the trade winds, while the west coast has tropical rainfall and aridity in the cool season: the humidity is increased here, between November and April, by the summer monsoon. coming from NO. The highlands experience temperatures mitigated by altitude and a rainfall regime similar to that of the west coast. In turn,
The variety of vegetal landscapes corresponds to these climatic differentiations, even if by now these are, for the most part, modified by human intervention. On the eastern side the rainforest dominates, which thins out going up towards the central plateau, with degradation phenomena (and consequent savannah-like formations) linked to the widespread practice of fires for the conquest of arable land. In western areas it is the conditions of greater aridity that impoverish the forest mantle, generating herbaceous-arboreal or even exclusively herbaceous savannah formations. Overall, the original vegetation, characterized by particular events in geological history (the isolation from the African block), seems to have resisted better in the southern areas due to the lower combustibility of the species.
As for the fauna, the long geographical isolation of Madagascar has produced an extremely peculiar population, in which many of the large groups of African fauna are absent and numerous endemics are present. Hyenids, Felids and Canids are missing, and Carnivores are represented only by some species of Viverrids and by the pit (Cryptoprocta ferox), endemic and only representative of the Criptoproctidae family. Also missing are Pholidotes, Tubulidentates and Iracoidea, and herbivores (Artiodactyls, Perissodactyls, Proboscidians), with the exception of the Potamocero (Potamochoerus porcus). Insectivores are represented by Tenrecids (tenrec); the Rodents from various endemic species. The Primates include three families, all exclusive to Madagascar: Lemuridae, Intridae and Daubentonidae. To the former belong 6 genera and at least 14 species, with dimensions ranging from those of a mouse to those of a cat, mostly nocturnal and arboreal, social, with a more or less opposable thumb; the Intridi include 4 species, larger than those of the lemurs; the Daubentonids are represented by the aye-aye only (Daubentonia madagascariensis), nocturnal and characterized by the third finger of the hand shaped like a tool, used to capture larvae, extract the contents of eggs and nuts, bring water to the mouth. Among the other Vertebrates, the Reptiles are interesting for the number of species (about a hundred Chameleonids) and for the presence of South American elements (Boids, Iguanids) to be considered Gondwanian relics; as well as the birds, not very extinct, of the genus Aepyornis, related to the Dinornis of New Zealand. Due to the extraordinary richness of biodiversity, Madagascar represents an environment of exceptional naturalistic interest; but, exposed to the threats of deforestation, erosion and drying up, it is considered an ecological emergency by international environmental associations. The government has established some protected areas, the total extension of which is around 5 million ha (2008).
