Many small islands are characterized by a high level of endemism. For example, Madagascar has the highest number of endemic species of any country in Africa, and ranks sixth in the world. Up to 8 000 of the 9 500 species of higher plants and over 50 per cent of all vertebrate species found on the island are known or thought to be endemic. In Mauritius, around 50 per cent of all higher plants, mammals, birds, reptiles and amphibians are endemic, and the Seychelles has the highest level of amphibian endemism of any island country in the world (UNEP 2002). Over 1 200 species of reef fish, 250 species of haematitic corals and 285 species of algae have been identified in the Maldives. In addition, five sub-species of seabirds have been identified as endemic to the Maldives (UNEP RRC-AP 2003). Despite such richness in biodiversity, many species in SIDS already face extinction (Table 2). Virtually all the SIDS have species threatened with extinction and these total about 1 680 (UNSD 2003), excluding Madagascar but also including more developed countries such as Singapore and Malta. Biodiversity is threatened by habitat degradation/loss, alien species, overexploitation of living resources, climate change, and other factors.

The Pacific Islands contain the world’s highest proportion of endemic species per unit of land area or human inhabitants. There are already far too many examples of illegal access, overexploitation, and extinction of Pacific Island biological resources, and the loss of associated traditional knowledge (SIDSNet 2003c).
Coral reefs, among the most biologically diverse ecosystems, have experienced widespread degradation in all three SIDS regions due to global warming, pollution, destructive fishing practices and other pressures (Burke and others 1998, Wilkinson 2000). Many poor people are economically dependent on coral reefs and their degradation has significant implications for poverty in SIDS (Wittingham and others 2003). Likewise, reefs underpin the lucrative tourist activities of many SIDS and their economies.
A recent study shows that up to 80 per cent of shallow-water reefs in some areas of the Caribbean have been destroyed (Gardner and others 2003). However, reefs in deeper waters of the Caribbean appear to be in better condition (Kramer 2003).
Many SIDS have established both marine and terrestrial protected areas. Since 1961, over 50 marine reserves have been established in the Caribbean, with the rate of establishment increasing since the mid-1980s (Appeldoorn and Lindeman 2003).