Fony baobab  (Adansonia rubrostipa)

Classified as Lower Risk/near threatened (LR/nt) on the IUCN Red List (1).

Like all baobabs, the fony baobab is a distinctive and rather bizarre-looking tree, with a massive, smooth, swollen trunk, and a relatively compact crown of short, thick branches (2) (3). The shape of this species is quite variable, ranging from tall and columnar to small and bottle-shaped, and there is usually a distinct constriction beneath the branches (2) (4) (5). The outer bark is reddish brown to grey in colour, peeling off in thin layers (2) (5) (6), and there is a thin photosynthetic layer beneath. The crown of the tree is irregular in shape, typically with short, horizontal branches that turn upwards at the ends (2) (5), while the leaves are palmate, each composed of three to five leaflets, and borne on a three to seven centimetre long stem. The leaflets measure up to 13 centimetres in length, and have distinctly toothed edges (2) (5) (7).

Juvenile baobabs typically have slender, tapering trunks, which are often swollen at ground level. The soft, fibrous wood of these species appears to store water, with the diameter of the tree’s swollen trunk varying depending on rainfall (2).

The fony baobab is endemic to Madagascar, where it is found along the west coast, from Soalala in the north to near Itampolo in the south (1) (2) (4) (5).

This species occurs in dry deciduous forest, spiny forest and sublittoral scrub, growing on well-drained limestone and calcareous soils (1) (2) (4) (5). Like most baobabs (3), the fony baobab is found in lowland areas, up to elevations of around 500 metres (5).

The fony baobab is a deciduous tree, bearing leaves from November to April, and flowering between February and April, although sometimes as late as June. The flowers are large, showy and sweet-smelling, and open just before or soon after dusk, producing copious amounts of nectar but remaining reproductively receptive for just one night (2) (3) (5) (8). The flower bud, which is borne at the base of a leaf, is elongated, green and cylindrical, measuring up to 28 centimetres in length, and opening to reveal a bright red inside surface. The long petals are bright yellow to orange-yellow in colour, and are significantly shorter than the numerous stamens, a feature which helps distinguish the fony baobab from other, similar species (2) (5) (7) (8).

The main pollinator of the fony baobab is believed to be a long-tongued hawk moth, Coelonia solanii, although two nocturnal lemur species also visit the flowers and may play a role in pollination (2) (4) (8). The fruits of this species ripen by October or November (4) (5), and consist of a large, dry, rounded berry, inside which numerous kidney-shaped seeds are embedded in a chalky or spongy pulp. The fruit has a thick, woody outer surface, and is covered in dense reddish-brown hairs (2) (5) (7). In Africa, the tasty, nutritious pulp of baobab fruits attracts large mammals such as elephants and baboons, which serve as seed dispersers. However, there are no animals on Madagascar which are known to disperse the seeds of Madagascan baobabs, and it is possible that the original dispersers became extinct when humans colonised the island (2) (3) (6). Unlike some other Madagascan baobabs, the seeds of the fony baobab are unlikely to be dispersed by water, as the species rarely grows near rivers or streams (2) (4). A number of species, including lemurs and birds, are likely to feed on and destroy the fruits and seeds, but are not thought to act as seed dispersers (6).

The fony baobab has a wide distribution and is not currently considered at high risk of extinction (1) (2). The species is not logged for its timber (6), although it does provide various non-timber products, including edible fruits, seeds and roots, and sheets of wood from fire-killed trees, which are used as thatch. The fruits of the fony baobab are traditionally collected by hammering wooden pegs into the trunk, in order to climb the tree, and these baobabs are also sometimes felled to encourage a popular edible fungus to grow on the rotting wood. However, these forms of utilisation do not occur extensively across Madagascar, and are not likely to pose a significant risk to the species at present (2) (4) (5) (6).

Probably of greatest threat to the fony baobab is habitat loss, with some populations in decline due to forest clearance for pasture and for charcoal production. Those to the north of Toliara are considered most at risk (1) (2) (4) (5). The long generation time typical of baobabs makes the fony baobab particularly vulnerable (1), and there is also concern at the low level of regeneration in disturbed habitats, exacerbated by high seed predation and low levels of seed dispersal (6).

As the dominant tree species in many of Madagascar’s western deciduous forests (2) (4) (5), the fony baobab provides a valuable resource for a range of species, including humans (2). It is reported to occur in a number of protected areas, including Kirindy Forest and Tsimanampetsotsa and Namoroka National Parks (4), and is unlikely to come under great threat from the harvesting of its fruits and seeds. However, felling of this iconic tree should be discouraged to help its populations to remain secure (5).

To find out more about the fony baobab and about conservation in Madagascar, see:

• Wickens, G.E. and Lowe, P. (2008) The Baobabs: Pachycauls of Africa, Madagascar and Australia. Springer, London.
• Madagascar Wildlife Conservation:
  http://www.mwc-info.net/en/