Round Island is an offshore islet, situated 22.5 km off the north-east coast of Mauritius, it is the second largest of Mauritius’ offshore islands with an area of 214 ha and high point of 280m. Round Island was classified as a Nature Reserve in 1957, it is administered jointly by the National Parks and Conservation Service (NPCS) and the Mauritian Wildlife Foundation.
Access to the island by boat is very difficult and dangerous as the island has a completely rocky shoreline and the sea is usually very rough. The only reliably safe and easy access to the island is by helicopter.

The weather on the island can be characterised as being warm and windy. The driest period extends from September to November during which time droughts are frequent. The wettest period is concentrated between December and March which is also the time when tropical cyclones can occur, associated with winds that sometimes exceed 250 km/h and with rainfall of high intensity. Temperatures on Round Island vary – autumn and winter months usually fall in the range of 22 to 30 degrees Celcius whereas in summer the temperature can soar to 50 degrees C in the open.

The island is a basaltic volcanic cone, probably dating between 25,000-100,000 years. Slopes are generally steep, particularly on the upper third of the island. Over half of the island is covered in bare rock.

Round Island supports the last remnant of a lowland palm rich community that formerly covered the dry lowland areas of Mauritius. The palm community is made up of several species of palms that are endemic to Mauritius. The hurricane palm Dictyosperma album var. conjugatum is Critically Endangered with only one surviving wild individual on Round Island. The Round Island bottle palm is also restricted to Round Island and is now regenerating well on the island. Latania loddigesii is the major palm covering extensive areas on the western and northern slopes. The Round Island population of Pandanus vandermeerschii screwpine, or ‘Vacoas’, is the largest remaining population of this species. With the disappearance of the hardwood forest, only two native hardwood species, Gagnebina pterocarpa and one individual of Fernelia buxifolia managed to survive. Recently a number of other hardwood species have successfully been re-introduced to the island.

Round Island is internationally famous for its reptile community. Seven to eight species of reptiles still exist on Round Island; all of these are endemic taxa to Mauritius. Four to five species are now restricted to Round Island, Guenther’s Gecko, Telfair’s Skink, Keel-scale Boa, Burrowing Boa (possibly extinct), and Durrell’s Night Gecko. Known reptile extinctions from Round Island include giant tortoises.

Round Island is also an internationally important seabird island. It has the only Indian Ocean breeding colony of Trindade Petrel. The taxonomic position of this petrel is still unresolved. Round Island holds important colonies of Wedge-tailed Shearwater, Red-tailed Tropicbird and possibly also the White-tailed Tropicbird in the Mascarenes and these colonies are of international importance. Breeding Bulwer’s Petrel and Black-winged Petrel have also recently been found on Round Island, the only known breeding ground for these species in the Indian Ocean.

Unlike many small tropical oceanic islands around the world, Round Island has still retained many of its original elements and is the only relatively large island, in the Mascarene group, free of introduced mammals. It is also one of the very few remaining elevated tropical islands in the world that is rodent free. The island has a largely intact bird and reptile community and is free of all introduced mammals and other alien exotic vertebrates are restricted to house sparrows and barred ground doves and the occasional vagrant such as the red whiskered bulbul. The numbers of introduced insect species is thought to be low. The risk of introducing alien vertebrates, particularly house geckos and small rodents and also persistent weeds and invasive insects such as ants are a growing concern.

Mauritian Wildlife Foundation has rostered permanent wardens on the island. They have the day-to-day responsibility for running the island.

So far rodents, house geckos, insect pests and major woody weeds have not been able to reach Round Island, probably due to the large distance that separates the island from mainland Mauritius and difficult access. However their introduction to the island is a real possibility if precautions during visits to the island are not adequately taken. The biodiversity of the island is very vulnerable to any alien species introduction. Rodents, in particular rats, could cause mass extinction of the reptiles, birds and plants - as has been the case on mainland Mauritius and other islets. The survival of reptile community is dependent on the absence of such predators.

To download the Round Island Quarantine Document, please see in the Newsletter section.

Work on Round Island could not have progressed so well without the field station, which has ensured permanent presence on the island. The station has gas cooking facilities, limited 12, 24 and 240 volt power supply, electric lights, bunks, a small office and tools/hardware storage area. The island has VHF radio comm.’s with MWF Office, MWF house and the other MWF field stations + 2 handheld VHF radios. A radio link phone to the main Mauritius Telephone network is installed which allows full telephone access together with internet and e-mail. The island also has a modern and hygienic composting toilet. Living is communally based; everyone is expected to take his or her turn.

Sponsored By:
Mauritius Commercial Bank
National Parks and Conservation Service
The Darwin Initiative

Last update: 16 January 2008