Environment

Madagascar’s long isolation from the neighbouring continents has resulted in a unique environment supporting a mix of plants and animals, many of which can be found nowhere else in the world; some ecologists refer to Madagascar as the ‘eighth continent’.

Madagascar is characterised by five distinct ecosystems:
• tropical moist forests ranging from rainforest to high elevation scrub and sambirano forest (which serves as a transition between moist and dry forests) that extend from the north down the east coast and into the higher ground of the central plateau and Tsarantanana Massif;
• dry deciduous forests in the northwest that extend down the west coast and round to Fort Dauphin in the south including the endemic spiny forest around Toliara and Fort Dauphin which is home to large numbers of endemic plants and animals;
• secondary communities of grassland - once much of this was forest but slash-and-burn activity, locally called tavy, means much of it has given way to a sea of grass - palm savannah, secondary forest (re-growth after slash-and-burn), scrublands (again often the result of slash-and-burn agriculture) and cactus scrub;
• wetlands around lakes, marshes and swamps in the coastal areas and what is thought to be one of the world’s largest expanses of mangrove forests;
• and around 1000km of coral reefs.

Madagascar’s plant life is wide-ranging and has a high proportion of endemic species. In the spiny desert 95% of the plants are endemic to its unique environment including six of the world’s eight species of baobab trees.

It has a relatively small number of birds - 258 species - although of these 115 are endemic species, with 36 endemic genera. It was also once home to the now extinct Elephant Bird, which weighed over 1000 pounds and stood ten feet tall.

There are over 300 species of frogs in Madagascar, 99% of which are endemic, and a similar number of reptiles including lizards, chameleons, geckos, snakes, turtles, tortoises and crocodiles, with over 90% of these also endemic.

Alongside this are a huge number of invertebrates including over 1000 species of spider, and huge numbers of beetles, millipedes, butterflies, stick insects, praying mantis, scorpions and the endemic Madagascan Hissing cockroach.

Madagascar’s mammal population is similar, of the six orders of mammals found on the island there is a wide range of diversity. Apart from bats, it is thought that all the non-endemic mammals are introduced. The lemur, or Maki, is the most well known with 40 documented species, all of which are endemic.

Alongside the lemurs live tenrecs (insect eaters vaguely resembling hedgehogs), fossa (looks like a dog / puma), falanouc (like a stocky cat with a pointed nose and back legs longer than the front), civet and several species of Malagasy mongoose.

Surrounding the island are an extensive network of coral reefs and formations - several authors (e.g., Gabrié et al. 2000) have estimated the length of coral reefs in Madagascar. Inspection of marine charts indicates 1130km of fringing reef, 55 km of reef around islets and islands or patch reefs, 52 km of true barrier reef (all in the Toliara region), and 1711km of submerged coral banks and shoals, or a total of 3540km of coral formations.

While Madagascar is particularly known for the spectacular barrier reefs of the Toliara region, equally impressive is the existence of an ancient submerged barrier reef parallel to the western and north-western continental shelf. The ancient reef is manifested as a string of banks and shoals, sometimes broken by passes, at a general depth of 15 to 30m with frequent peaks to 10m or less.

The principal concentrations of emergent reefs are in the northeast (Cap d’Ambre to Toamasina - 417 km), southwest (Androka to Morombe - 458 km), and the northwest (Mahajanga to Cap d’Ambre (578 km). The principal zone of submerged reef is 1418 km long and runs from Morombe to Cap d’Ambre (Cooke et al. 2000).

These reef networks are home to a wide range of marine life, including humpback whales, dolphins, marine turtles, and over 56 species of shark.

For more information about Madagascar’s reef systems and marine life:
Coral Reefs of South-west Madagascar
ReefDoctor’s scientific reports and papers

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