25 Jul The Baobab – A Migrant From Madagascar
A giant baobab towering over the surrounding bush, sometime with an elephant or two feeding nearby, is one of the iconic images of Africa. Despite this, recently published genetic research shows that the species of baobab which grows in Africa, (Adansonia digitata) originated in Madagascar, as did the Australian baob.
Both the African baobab and boab, “….almost certainly left Madagascar as seeds or seedlings, floating on piles of debris clumped together as rafts, that were carried out to sea by rivers swollen from flash storms,” Professor Andrew Leach, one of the researchers involved in the project wrote in a recent edition of The Conversation. “The early African baobab pioneer probably arrived within the last 12 million years”.
“From there it expanded in number, often with the help of elephants which eat its seeds,” Professor Leitch added. “Many baobab seeds pass through elephants undamaged and are deposited in piles of dung, up to 65 km away from where the elephant ate the baobab fruit.”
Over the millennia a complex set of process has resulted in the African baobab becoming genetically isolated from its parents in Madagascar.
African baobabs are massive trees that support a diverse range of life. Some species live in hollows in the tree’s trunks, other feed on their fruit and nectar, and the baobab’s extensive root system helps slow erosion.
The researchers point out that their enormous trunks are “…hollow cylinders of low-quality wood containing many water-filled living cells. Some of the largest and oldest baobab trees in Australia have been estimated to hold more than 100 000 liters of water”.
This can have disastrous consequences for the African baobab during droughts because elephants sometime cause extensive damage to the trees as they strip the bark from the trees so they can utilise the water stored in the wood.
In addition to showing that all baobabs come from Madagascar the research, published in a paper entitled “The rise of baobab trees in Madagascar” has significant recommendations for the conservation of the giant trees on the island.
“Two of the Madagascar species are already listed as endangered, based on the International Union for the Conservation Red List criteria,” the researchers note. “They exist in small numbers and can only survive in certain habitats, which are shrinking. We recommend that their extinction risk threat is raised to the next level, critically endangered, so that they can be protected.”
