The Zurich-Aldabra Research Platform (ZARP) was initiated in 2011 with money from the Forschungskredit of the University of Zurich (UZH). ZARP is a multi-disciplinary collaboration between scientists based mainly at the University of Zürich and the Seychelles Islands Foundation (SIF) that aims at supporting local SIF staff based on Aldabra Atoll in their research on the Aldabra giant tortoise.
Photos (from left to right): Aldabra giant tortoise (Jock Currie), Aldabra's limestone landscape (Christina Quanz) and Aldabra rail (Jock Currie)
Aldabra Atoll, located in the western Indian Ocean, is the second-largest raised coral atoll in the world. It has a land area of 155.4 km², but an average height above sea level of only around eight meters. The atoll consists of a ring of four major islands: Grand Terre, Malabar, Polymnie and Picard enclosing a large lagoon, which floods and empties through a series of narrow channels with the rise and fall of the tide. The atoll is unique in the region; its isolation and remoteness have protected it from undue human influence and it stands as an unspoilt Eden, while surrounding islands have suffered heavy degradation. Aldabra is a place of superlatives, supporting many globally-threatened species, such as green turtles (Chelonia mydas), hawksbill turtles (Eretmochelys imbricata), the dugong (Dugong dugon), the Aldabra giant tortoise (Aldabrachelys gigantea) and the Aldabra rail (Dryolimnas cuvieri aldabranus), the last surviving flightless bird of the western Indian Ocean. In recognition of its special status, Aldabra was declared a UNESCO World Heritage Site in 1982 and a Ramsar Wetland Site of International Importance in 2009.
Photo from Google Earth
The Seychelles Islands Foundation is a public trust established in 1979 charged with the management and protection of Aldabra and the other World Heritage Site of Seychelles, the Vallée de Mai. The Foundation organises research and carries out basic monitoring and surveys on the atoll as well as managing the research station and a team of rotating staff on the atoll. The SIF team and associated researchers, usually 10–15 people, have formed the only human population on Aldabra for over 30 years.
Population Genetics: ZARP is establishing a detailed study of the Aldabra giant tortoise, the last remaining native population of giant tortoises in the Indian Ocean. Our main focus is a sub-population on the third largest island, Picard. Here we hope to sample as many individuals as possible and to reconstruct family relationships, together with information on pathogen loads and nutritional status. This will be complemented by an island-wide survey of other animals.
Tortoises, Vegetation and Climate: Tortoise densities on Aldabra are extremely high and herbivore biomass per unit area generally exceeds that typically found in ecosystems dominated by large mammalian herbivores. The vegetation on Aldabra is highly seasonal, and we plan to uncover the links between climate, vegetation and tortoises using satellite images, LIDAR, long-term tortoise counts and vegetation exclusion plots. This will provide vital information on the possible impacts of climate change on the atoll.
Photos by Christina Quanz
Photo by Michal Šúr