IUCN Management Category IV (Managed Nature Reserve)

Biogeographical Province 3.25.13 (Mascarene Islands)

Geographical Location About 4km north of Cap Malheureux, between the Cape and Flat Island. 19°56'S, 57°37'E.

Date and History of Establishment 14 January 1970

Area 76ha

Land Tenure Government

Altitude Sea level to 162m

Physical Features The island comprises a mass of volcanic rocks, forming a wedge-shaped cliff with stratification dipping on one side towards Mauritius and the other towards Ile Plate (Flat Island). The top of the cliff is flat with a layer of volcanic soil. The island is composed of tuff, though this is overlain by basalt flows in the eastern part. The coast is rugged, and the surrounding rough sea prevents reef formation. Rainfall averages 900mm per year, and falls mainly between November and April during the warm, wet summer. Mean temperature during February is 27.8°C, and during July 21.9°C. The islands are subject to cyclones in winter.

Climate No information

Vegetation Seventy species of plant are found on the island, with eight species being endemic to the Mascarenes. These form four basic vegetation types, Zoysia grassland, Padanus/Latania scrub, Heteropogon thorn scrub, and coastal communities. There are extensive colonies of the endemic liliaceous aloe-like plant Lomatophyllum tormentorii (a species endemic to Gunners Quoin and Round Island) in the Zoysia grassland, and a few individuals of Dracaena concinna, and the endemic shrubs Scutia myrtina and Eugenia lucida is the thorn scrub. The fan pine Latania loddigesii is now rather less common than the screw pine Pandanus vandermeerschi. The islet is much invaded by exotic weed species (there are some 36 introductions), and thicket of introduced Santalum album has become established over a large area on the top of the cliff.

Fauna The island is a breeding site for three species of seabird, the white-tailed tropic bird Phaethon lepturus, the red-tailed tropic bird Phaethon rubricauda rubricauda, and the wedge-tailed shearwater Puffinus pacificus chlororynchus. Four species of reptile are also found, two skinks Scelotes bojerri and Ablepharus boutonii, and two geckos Phelsuma ornata and Nactus coindemirensis sp. nov. (the last endemic to Gunner's Quoin), although three further species were known to be present before the introduction of exotic mammals.

Cultural Heritage No information

Local Human Population No information

Visitors and Visitor Facilities No information

Scientific Research and Facilities A survey of the islet was recently carried out (Bullock et al., 1983), as part of an expedition to this islet and Round Island. One aim was to assess the suitability of Gunner's Quoin for the introduction of Round Island reptiles, which have been captive bred by the Jersey Wildlife Preservation Trust. The island was considered unsuitable because of the presence of black rats Rattus rattus.

None

Conservation Value No information

Conservation Management Total. Protected under the Forest and Reserves Act 1983.

None

According to North and Bullock (1986), effective control of invasive plants and rats in necessary before any reintroduction of native plants and animals could be reasonably contemplated. However substantial resources, currently beyond the Mauritian authorities, would be required.

Management Constraints The effects of various exotic species, both plant and animal, have had very severe effects on the native vegetation. For example, rats are reported to be contributing to the low regeneration rate of fan palm and screw pine. Also contributing to this is the invasion by exotic ruderal species such as Santalum album. The black-necked hare Lepus nigricollis is also found as an exotic, though numbers are reported to be low. (This was introduced following an abortive attempt to introduce rabbit.)

Staff Periodic visits are made by Forestry and Fisheries Department staff.

Budget None

Local Addresses

Forest Department, Ministry of Agriculture, Fisheries and Natural Resources, Curepipe.

References

Ayres, P.H.B. (1860). Geology of Flat and Gabriel Islands. Trans R. Soc. Arts and Sci. Mauritius, New Series Vol. I, part II: 220-232.

Bullock, D., North, S. and Grieg, S. (1983). Round Island Expedition 1982. Final Report.

Bullock, E.J., Arnold, E.N. and Bloxham, Q. (1985). A new endemic gecko (Reptilia: Gekkonidae) from Mauritius. J. Zool. Lond. 206: 591-599.

Bullock, D.J. (1986). The ecology and conservation of reptiles on Round Island and Gunner's Quoin, Mauritius. Biological Conservation 37: 135-156.

Cheke, A.S. (in press). A review of the ecological history of the Mascarene Islands with particular reference to extinctions and introductions of land vertebrates. In: Diamond, A.W. (Ed.) Studies of the Mascarene avifauna, Cambridge University Press.

North, S.G. and Bullock, D.J. (1986). Changes in the vegetation and populations of introduced mammals of Round Island and Gunner's Quoin, Mauritius. Biological Conservation 37: 99-117.

Date 1984