Standing up to 30 metres tall, Madagascar’s giant baobab trees have towered over the island for thousands of years – but as the large animals that used to spread their seeds have died out, the trees’ survival is threatened. New research indicates that much smaller species have an unexpected role in helping baobabs thrive.
One of Madagascar’s most photographed tourist sites is the Avenue of the Baobabs near the city of Morondava, in the west of the island, where giant, stately baobabs line a dirt road.
But the trees are endangered, partly because the megafauna that once dispersed their seeds are now extinct.
“The hypothesis in the first place was that they are orphan plants, meaning that without major seed dispersers like giant animals, their survival is challenging,” says Seheno Andriantsaralaza, a researcher at the University of Antananarivo.
Baobabs like the ones growing in Morondava are known to science as Adansonia grandieri, or in Malgasy as renala. While baobabs in mainland Africa have elephants to eat and scatter their seeds, the so-called megafauna once reputed to have done that on behalf of renala baobabs – giant lemurs and giant tortoises – went extinct centuries ago.
Scientists say there’s no evidence any of the large lemur species still living in Madagascar can break open the pods of renala baobabs, or chew off the chalky pulp surrounding each of the tiny brown seeds packed inside.
As secondary dispersers the tuft-tailed rats appear to be compensating for the absence of larger, long-extinct animals, says Andriantsaralaza.
Read also:
Madagascar: can finding food alternatives save the endangered lemur?
Sparrow-sized bat confirmed as Mozambique’s newest mammal
Zimbabweans barking up the wrong tree with ‘silly’ English names
