Ile aux Aigrettes is a small 26 hectare island in the Mahebourg Bay. It takes its name after the egrets that once lived there. It is the last refuge of the dry, coastal forest, an ecosystem once common around much of coastal Mauritius but lost through the action of man.
This type of forest was rich in the unique and critically endangered species of ebony (Diospyros egrettarum) named after Ile aux Aigrettes, the endangered Bois de Chandelle (Dracaena concinna), and a species of orchid Oeniella aphrodite, amongst others. Endemic animals included the beautiful turquoise and red lizard, the Ornate Day Gecko.
In 1965 Ile aux Aigrettes was declared a Nature Reserve to save this last remnant of not only Mauritian, but also Mascarene coastal forest. Already by then the island had become damaged ecosystem, highly infested by introduced weeds and rats, putting immense pressure on the native species. The fast growing weeds were invading the island, choking off the native plants, and the rats were predating heavily on the delicious fruits preventing regeneration.
In 1985 the Mauritian Wildlife Foundation put a watchman on the island and started restoration work. A weeding programme to eradicate introduced invasive plants such as the False Acacia and the spiny Prune Malgache was launched.
In 1991 the rats, cats and mongooses previously present on the island were successfully eradicated paving the way for further work. The Mauritius Kestel was reintroduced for the first time. However, this unique bird of prey prefers the nearby mainland Bambous Mountains and rarely comes back to the island.
Once the rats were gone there was a dramatic emergence of Ebony seedlings. However, considerable work had to be done in terms of habitat restoration. In 1996, the Foundation obtained a grant from the Global Environment Fund through the World Bank to continue restoration work on Ile aux Aigrettes. An aggressive weeding programme was launched involving a lot of sweat and blisters but today nearly 90% of the island has been weeded and replanted with native plants.
In 1997, a Nursery was built for the production of endangered native plants for replanting on the island. The Nursery produces about 30,000 plants per year of which most are planted on Ile aux Aigrettes during the rainy season (February to April).
To date 20 endangered endemic plant species have been introduced to the island, including the critically endangered Round Island Bottle Palm and the Round Island Hurricane Palm, of which only one adult tree remains.
Hand in hand with this has come the reintroduction of the native animals once known to have existed on the island. In 1994, an aviary was set up on the island and the Pink Pigeon was reintroduced on the island. Today there are over 75 pink pigeons flying free, the only wild population of these birds to be seen by the public anywhere in the world.
Mauritius in the past had 2 species of endemic tortoises, but these became extinct about 200 years ago through excessive predation by man. In 2000, 18 Giant Aldabran Tortoises were released on Ile aux Aigrettes to simulate the impact of browsers on the island’s vegetation. It is the first time that giant tortoises can be seen in this type of ecosystem since the extinction of the Mauritian species. It is hoped that, as soon as the necessary research has been done, the tortoises will be freed to roam free throughout the island.
There are still a number of introduced exotic/alien animal species present on the island. These include the Indian House shrew, Indian wolfsnake, Giant African land snails. These affect native animal species as competitors and predators. Currently methods are being looked into for their eventual eradication. The Round Island Telfair’s skink, a clawed lizard, has been brought back in semi captivity, waiting the day for its release on the island when the shrew has been controlled.
Finally, once conditions are suitable endangered native passerines and indigenous reptiles will be reintroduced as a further move towards the reconstruction of the island’s ecosystem.