Giant tortoises slowly but surely rescue tropical island's ebony forest

By Daily Mail Reporter


-Intensive logging had decimated the ebony forest which once covered the Ile aux Aigrettes, off Mauritius
-Aldabra tortoises were brought in 2000 to eat the fruit of the ebony tree and disperse the seeds in their faeces

'Rewilding': British scientists brought the giant Aldabra tortoise to the Ile aux Aigrettes, off Mauritius, to help disperse ebony tree seeds


Giant tortoises have rescued the ecology of a tropical island devastated by deforestation in a successful example of 'rewilding'.

British scientists brought the giant Aldabra tortoise - Aldabrachelys gigantea - to the Ile aux Aigrettes, off Mauritius, to help disperse ebony tree seeds.

Intensive logging that lasted until the early 1980s has decimated the ebony forest which once covered the 25-hectare island.


Even though logging ceased 30 years ago after the disappearance of the island's native Aldabra tortoises, large tracts of land remain denuded of trees. This is especially true in the northern and eastern coastal areas nearest to the mainland.

The tortoises, which can reach a length of almost 4ft and weigh 500lb, were re-introduced in 2000 to eat the fruit of the ebony tree and disperse the seeds in their faeces.

The strategy worked better than experts had hoped, leading to the widespread establishment of new ebony seedlings in heavily logged parts of the island.

Not only were seeds sown across the island, but passing through the tortoise's gut seemed to improve their germination.


Going about his business: The tortoises were re-introduced in 2000 to eat the fruit of the ebony tree and disperse the seeds in their faeces


Lead scientist Christine Griffiths, from the University of Bristol, said: 'Our results demonstrate that the introduction of these effective seed dispersers is aiding the recovery of this critically endangered tree whose seeds were previously seed-dispersal limited.

'Reversible rewilding experiments such as ours are necessary to investigate whether extinct interactions can be restored.'

Colleague Professor Stephen Harris said: 'Ecological restoration projects generally involve the plant community, as more often the animal components are extinct.

'There is, however, increasing evidence that restoration ecologists should be most concerned with the decline of species interactions, rather than species extinctions per se.

'Species interactions structure ecological communities, and provide essential ecosystem processes and functions such as pollination, seed dispersal and browsing, that are necessary for the self-regulation and persistence of a community.'

Details of the project are reported in the journal Current Biology.


source:dailymail