Terrestrial and Marine Ecology of Desnoeufs, Amirantes, Seychelles.

The Amirantes group, Seychelles, comprises 24 islands and islets lying between 5o and 6o south of the equator on the Amirantes Bank, western Indian Ocean. The islands were discovered by the Portuguese navigator Vasco de Gama on his second voyage to India in 1502, soon after acceding to the rank of Admiral, and the islands were subsequently named Ilhas do Almirante or Admiral’s Islands. Desnoeufs was the fifth island located by the Chevalier du Roslan in 1771 and he named it Ile des Neufs (Lionnet, 1970). It is the most southerly of the main group of Amirante islands, 138 km from the reefs and shoals of African Banks at the northern end. It lies 13 km south-west from its nearest neighbour in the Amirantes, the island of Marie-Louise and 290 km southwest of the island of Mahé in the granitic Seychelles. Desnoeufs was described as being well-wooded by the du Roslan Expedition in 1771 (Wilson, 1983). Today (2005) it is not wooded but it is well vegetated, a contrast to Baker’s observations in 1960 when he reported an island surface ‘bare of vegetation except for a small clump of littoral scrub on the sand by the landing place’ (Baker, 1963). In the mid-1900s, Marie-Louise developed both agriculture and guano production and it is thought that in these early days, Desnoeufs was run in a similar way, with the removal of 100 tonnes of guano, although agricultural production was much less successful than on the neighbouring island (between 1900 and 1910, about 300 pigs were free-ranged on the island (Wilson, 1983)). Five coconut palms were planted on Desnoeufs in 1900 (Ridley and Percy, 1958) and rows of pits indicate that there were once plans to develop a coconut plantation on the island but these never came to fruition. The original coconut palms are still standing on the island and were observed as the only trees on the island in 2005, with the exception of a single Hibiscus tree. Wilson (1983) speculated that, under guano exploitation, the almost complete removal of the littoral hedge at the same time as the removal of the natural woodland cover exacerbated the difficulty of tree regeneration…