Aldabra Atoll

Aldabra Atoll

The atoll is comprised of four large coral islands which enclose a shallow lagoon; the group of islands is itself surrounded by a coral reef. Due to difficulties of access and the atoll's isolation, Aldabra has been protected from human influence and thus retains some 152,000 giant tortoises, the world's largest population of this reptile.

Atoll d'Aldabra

L'atoll comprend quatre grandes îles de corail qui enferment une lagune peu profonde. L'ensemble est lui-même entouré d'un récif de corail. En raison des difficultés d'accès et de l'isolement, Aldabra a été préservé de l'influence humaine et est devenu un refuge pour quelque 152 000 tortues terrestres géantes, soit la plus grande population mondiale de ce reptile.

جزيرة ألدابرا المرجانية

تتألف الجزيرة من اربع جزر مرجانية كبيرة تحوي بحيرة شاطئية ضحلة ويحيط بها رصيف مرجاني. ونظراً لصعوبة النفاذ الى ألدابرا المنعزلة، ظلت بمنأى عن التأثير البشري وأصبحت ملاذاًً لنحو 152000 سلحفاة برية عملاقة أي لأكبر تجمع لهذه الزواحف في العالم.

source: UNESCO/ERI



source: UNESCO/ERI

Атолл Альдабра

Атолл состоит из четырех окруженных коралловым рифом больших коралловых островов, которые образуют мелководную лагуну. Из-за своей труднодоступности и изолированного положения атолл был предохранен от антропогенных воздействий, и здесь сохранилось порядка 152 тыс. гигантских черепах – самая большая в мире популяция этой рептилии.

source: UNESCO/ERI

Atolón de Aldabra

Este sitio está formado por una laguna poco profunda aprisionada entre cuatro grandes islas de coral que, a su vez, están rodeadas por un arrecife coralino. Su aislamiento y difícil acceso le han preservado de la influencia humana y han hecho de él un refugio para unas 152.000 tortugas gigantes, que constituyen la mayor población del mundo de este tipo de reptil.

source: UNESCO/ERI


source: NFUAJ

Aldabra atol

Het Aldabra Atol bestaat uit vier grote koraaleilanden die een ondiepe lagune insluiten. De groep eilanden zelf is omgeven door een koraalrif. Het Aldabra atol ligt in de Indische Oceaan en is een uitstekend voorbeeld van een verhoogd koraalatol. Aldabra is een van de grootste atollen ter wereld en bevat een van de belangrijkste natuurlijke leefgebieden voor onderzoek naar evolutionaire en ecologische processen. Door zijn ontoegankelijkheid en geïsoleerde ligging is het atol beschermd tegen menselijke invloeden. Om deze reden is het de thuisbasis van de grootste reuzenschildpadden populatie ter wereld; op het Aldabra atol leven er ruim 152.000.


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Aldabra Atoll (Seychelles) © UNESCO
Outstanding Universal Value

Brief synthesis

Located in the Indian Ocean, the Aldabra Atoll is an outstanding example of a raised coral atoll. Due to its remoteness and inaccessibility, the atoll has remained largely untouched by humans for the majority of its existence.  Aldabra is one of the largest atolls in the world, and contains one of the most important natural habitats for studying evolutionary and ecological processes. It is home to the largest giant tortoise population in the world. The richness and diversity of the ocean and landscapes result in an array of colours and formations that contribute to the atoll's scenic and aesthetic appeal.

Criterion (vii): Aldabra Atoll consists of four main islands of coral limestone separated by narrow passes and enclosing a large shallow lagoon, providing a superlative spectacle of natural phenomena.  The lagoon contains many smaller islands and the entire atoll is surrounded by an outer fringing reef. Geomorphologic processes have produced a rugged topography, which supports a variety of habitats with a relatively rich biota for an oceanic island and a high degree of endemism. Marine habitats range from coral reefs to seagrass beds and mangrove mudflats with minimal human impact. 

Criterion (ix): The property is an outstanding example of an oceanic island ecosystem in which evolutionary processes are active within a rich biota.  Most of the land surface comprises ancient coral reef (~125,000 years old) which has been repeatedly raised above sea level. The size and morphological diversity of the atoll has permitted the development of a variety of discrete insular communities with a high incidence of endemicity among the constituent species. The top of the terrestrial food chain is, unusually, occupied by an herbivore: the giant tortoise. The tortoises feed on grasses and shrubbery, including plants which have evolved in response to its grazing patterns. The atoll's isolation has also allowed the evolution of endemic flora and fauna. Due to minimal human interference, these ecological processes can be clearly observed in their full complexity.

Criterion (x): Aldabra provides an outstanding natural laboratory for scientific research and discovery. The atoll constitutes a refuge for over 400 endemic species and subspecies (including vertebrates, invertebrates and plants). These include a population of over 100,000 Aldabra Giant Tortoise. The tortoises are the last survivors of a life form once found on other Indian Ocean islands and Aldabra is now their only remaining habitat. The tortoise population is the largest in the world and is entirely self-sustaining: all the elements of its intricate interrelationship with the natural environment are evident.  There are also globally important breeding populations of endangered green turtles, and critically endangered hawksbill turtles are also present.  The property is a significant natural habitat for birds, with two recorded endemic species (Aldabra Brush Warbler and Aldabra Drongo), and another eleven birds which have distinct subspecies, amongst which is the White-throated Rail, the last remaining flightless bird of the Western Indian Ocean. There are vast waterbird colonies including the second largest frigatebird colonies in the world and one of the world's only two oceanic flamingo populations. The pristine fringing reef system and coral habitat are in excellent health and distinguished by their intactness and the sheer abundance and size of species contained within them.


The property includes the four main islands which form the atoll plus numerous islets and the surrounding marine area. It is sufficiently large to support all ongoing biological and ecological processes essential for ensuring continued evolution in the atoll. The remoteness and inaccessibility of the atoll limit extensive human interference which could otherwise jeopardize ongoing processes. As such, Aldabra displays an almost intact ecosystem, sustaining naturally viable populations of all key species. 

Protection and management requirements

The property is legally protected under national legislation and is managed by a public trust, the Seychelles Islands Foundation, with daily operations guided by a management plan. Boundaries are ecologically viable but the extension of the seaward boundary some 20 km into the sea would provide additional protection to the marine fauna. While the remoteness of the property has limited human interference, thus contributing for the protection of the biological and ecological processes, it also poses tremendous logistical challenges. Tourism is limited and carefully controlled. Whilst the property displays an almost intact ecosystem, protection and management need to address the constant threats posed by invasive alien species, climate change and oil spills, particularly in the event that oil exploration increases in the wider region.