Madagascar spiny thickets

Madagascar spiny forests
Spiny forest at Ifaty, featuring various Adansonia (baobab) species, Alluaudia procera (Madagascar ocotillo) and other vegetation
Ecology
Realm	Afrotropic
Biome	Deserts and xeric shrublands
Borders	Madagascar succulent woodlands, Madagascar lowland forests
Geography
Area	43,400 km2 (16,800 sq mi)
Country	Madagascar
Elevation	55–200 metres (180–656 ft)
Coordinates	24°54′S 44°12′E / 24.900°S 44.200°E / -24.900; 44.200Coordinates: 24°54′S 44°12′E / 24.900°S 44.200°E / -24.900; 44.200
Geology	Limestone and red sand
Climate type	Hot desert climate (BWh)
Soil types	sandy
Conservation
Conservation status	critical/endangered
Global 200	yes

The Madagascar spiny forests (also known as the Madagascar spiny thickets) is an ecoregion in the southwest of Madagascar. The vegetation type is found on poor substrates with low, erratic winter rainfall. The ecoregion contains an outstanding proportion of endemic plant species and is part of the Global 200.

Around 95% of the original flora in the spiny forests is endemic, which makes it the most unique ecoregion in Madagascar. Many constituent plants show extreme adaptations to drought. Spiny plants of the endemic subfamily Didiereoideae form a conspicuous component, especially towards the east. They are woody but distantly related to the cacti. The remaining component of the forests is dominated by members of the plant families Burseraceae, Euphorbiaceae, Anacardiaceae and Fabaceae, all of which have representatives elsewhere.

Notable inhabitants of the spiny thickets include the spider tortoise (Pyxis arachnoides) and the radiated tortoise (Astrochelys radiata), the gecko Ebenavia maintimainty, several lemurs including Verreaux's sifaka, Grandidier's mongoose, and eight endemic birds.

Existing reserves protect a maximum of 3% of remaining vegetation, including Tsimanampetsotsa National Park, Berenty Reserve and Beza Mahafaly Reserve. Andohahela National Park offers limited protection through its 'parcel 3' section. Elsewhere the spiny forest habitat is under pressure from human exploitation. The main impacting activities are burning for conversion to grazing land, harvesting for charcoal and firewood, and logging for construction.