Brief overview of the biogeography and history of the Aldabra

Aldabra atoll is the earth's belly-button, for several reasons. This ring shaped atoll is near the middle on most maps of the world. It has been forgotten about since early discovery; and received much less attention since the late sixties. It also reminds us, that once the earth was once we were all born from an untouched earth, a beautiful place, before the days of pollution, habitat destruction and over-exploitation that has happened in so many other places on earth.

Aldabra is a dormant volcano, which has since collapsed in the middle. The rise and fall of the and sea level over several thousands of years has breached its walls, and today several millions of liters of water fills and drain the big central lagoon every day through four channels. The landscape is really rough - known as champignon (or mushroom rocks). It is old coral that has eroded over millennia. From the steep drop off, reefs fringe the atoll, bordered by steep champignon cliffs and a few sandy beaches. A thin line of sandy dunes fringed with restio-like grasses follow. Gradually the grass gives way to more shrub like bushes, some like the pemphis scrub, which are like large overgrown hedgerows.The vegetation then becomes more mixed, and eventually the mangroves that line the lagoon starts.


Inside the massive (ca 97 km^2) lagoon all sorts of charismatic animals, like green and hawksbill turtles, eagle rays and rarely, dugongs feed on vast sea-grass beds. The lagoon acts as a nursery to several fish smaller fish who hide amongst coral, champignon and mangrove tributaries. The reefs holds many large fish, including several species of rockcod, snapper, shark and ray. It has not been fished for years-and-years other than subsistence for the ca 15 people living here. Consequently the fish are very large compared to those in other parts of the world, where fishing pressures remove the largest oldest most fecund individuals. One regularly sees large groups of semi-resident spinner dolphins and and humpback whales which migrate to the tropics during their breeding season. In the mangroves, frigate birds and boobies nest next to each other, when not fighting over food during aerial acrobatics that leave you jaw-dropped looking on in wonder.


On land there are lots of giant tortoises - like the ones on the Galapagos Islands, but 100 000 thousand of them. The tortoises are the largest herbivore on the atoll, and maintain critical ecosystem functions. Their constant grazing and slow but sure movement from one grassy patch to the next sows the undigested seeds of a variety of over 50 species of grass, creating a mosaic patchwork of grass species.

There a lots of rare birds. The white throated rail, is a endemic sub-species, and is the last flightless bird in the Indian Ocean. Cheeky little buggers that will peck you on your toes if you are not paying attention to them. We have one, fondly known as Bruce, living under our house. He joins us at meal times for crumbs that may fall you your plate.

The atoll was once under English sovereignty, and later handed back to the Seychellois. During English reign, their were proposals to turn the atoll into a military base for allies. There was a public outcry from several biologists, including the best established scientific body in the world, The Royal Society.  Even Darwin marvelled at the real natural museum of evolution during his voyage on the beagle. How could the world be so short sighted at that time to overlook the natural value of today, one of the last remaining true wild places? It is thought that the proposal to "develop" Aldabra into a military base was finally abandoned for financial reasons, rather than public conviction. For whatever reason, thankfully,  Aldabra is a UNESCO world heritage sight, and an IUCN strict nature reserve, to be preserved indefinitely.