NEWS
Figure 2 . The Aldabra giant photographed in the Anjajavy Reserve on 26 August 2022 . Chainsawpunk / Wikimedia Commons
How difficult was it to reintroduce this tortoise to Madagascar ?
In 2018 , Madagascar-based tortoise specialist and conservation biologist Miguel Pedrono worked with the government of Madagascar to reintroduce the Aldabra giant to the Anjajavy Reserve in the north-west of Madagascar . Grant Joseph , an ecologist and conservation biologist working in Madagascar , modelled the impact the tortoise could have on vegetation .
The first group of 12 giant tortoises , five males and seven females , arrived and were fitted with transponders before being released . Reintroducing the tortoise was far less daunting than anticipated . Two babies were born the year after the tortoises were resettled in Madagascar and in the five years since , another 152 tortoises have hatched .
All the baby tortoises ( hatchlings ) were taken to live in a tortoise nursery in Anjajavy soon after they were born , and will be returned to the wild once their carapace ( the convex part of the shell which is made up of the tortoise ’ s ribs , fused with bone ) is large enough to protect them from predators . Hatchlings are very small – so feral cats , dogs and rats are potential predators , as are raptors ( birds of prey ) and the fossa , Madagascar ’ s largest endemic carnivore .
Meanwhile , the juvenile tortoises are being raised in an environment that looks just like the one they will be freed into , so that they develop the foraging skills they need to survive in the wild . Through natural breeding , this project aims to have 500 wild giant tortoises in Anjajavy Reserve by 2030 and about 2,000 by 2040 .
Why is it important to bring the tortoise back ?
A man feeding a tortoise a vegetable . The giant tortoise comes up to the man ' s waist .
Our recent research has shown that much of Madagascar is burned annually by people to create grazing land for cattle . In other areas , woodland and forest is cut down , and the ground then burned for cropland . Our research predicts that reintroducing the Aldabra giant tortoise will limit such fires in the future . Tortoises limit fire by feeding on any grass or dry leaves on the forest floor , leaving less dry fuel available in these forests to catch alight .
The original , shady forests and woodlands of Madagascar also limited the ability of fire to spread . Without the tortoise helping seeds to germinate for the past 600 years , endemic trees have not reproduced as fast as they could
Figure 3 . The Aldabra giant seen in 2009 before the project to re-wild Madagascar began . Rhett A . Butler / Mongabay
have . We believe that reintroducing the tortoise will speed up the growth of forest and woodland considerably . On Rodrigues and Île aux Aigrettes islands in Mauritius , research shows that ebony forests returned after giant tortoises were reintroduced .
Our dream is to expand the Aldabra giants ’ habitats beyond the Anjajavy reserve , so that this tortoise can help regenerate forest and woodland across as much of Madagascar as possible . There are 100,000 Aldabra giant tortoises living on the 155km ² island of Aldabra in the Seychelles . On the Mascarene islands ( Mauritius , Rodrigues and Reunion ), giant tortoises once numbered in the many hundreds of thousands . But between 1700 and 1840 , all Mascarene giant tortoise species were driven to extinction by humans . We are hopeful of reintroducing the same kind of numbers to Madagascar through this project .
If the reintroduction continues to be successful , we are optimistic that we will be able to return these tortoises across their former rangelands one day , benefiting biodiversity and tourism . This will also enhance animal biodiversity : there will be a return to habitat mosaics with trees , supporting animals like lemurs , indigenous birds and chameleons .
People also stand to benefit , as Madagascar recently experienced a famine , which in some areas may have been worsened by climate change . The likely increase in tree cover following larger scale reintroduction will help reduce the impacts of climate change .
Grassroots Vol 24 No 1 March 2024 22