Global island conservation and research

under construction

Islands comprise a small proportion of the earth’s surface (some 5%) but support exceptional levels of diversity, with some 50,000 plant species and 15% of all mammals and birds being found on islands. Islands are vulnerable to disturbance, due in part to their isolation making recolonisation difficult, in addition island species are inherently vulnerable to extinction due to their small ranges. Accordingly it is to be expected that a high proportion of such species are threatened. For example some 20% of amphibians, 25% of mammals and 33% of birds considered to be threatened with extinction are restricted to islands. 88% of recent (i.e. since AD1500) bird extinctions have been on islands, 86% of reptile extinctions and 54% of amphibian extinctions. Consequently islands have been highlighted in several prioritization programmes such as the Global 200 ecoregions (25% of which are islands), Endemic Bird Areas (48% insular), biodiversity hotspots (29% exclusively made up of islands), Alliance for Zero Extinction sites (39%), 70% of coral reef hotspots. Island species may be at particular risk due to unusual evolutionary processes, such as a tendency towards flightlessness in many areas, which may contribute to the loss of 40% of the birds on New Zealand in 1,000 years of human history. A large number of alien species has been introduced to islands, and low diversity island ecosystems appear to be particularly vulnerable to the invasion of aliens, these have led to dramatic extinctions.
Ecological processes on islands may not be substantially different from those on continental areas, differing mainly in size and isolation. They can be considered to be miniature versions of continental ecosystems and thus may represent microcosms of processes operating at larger scales elsewhere. As a result of this changes in island ecosystems will mirror global changes but will be apparent earlier. Studying islands will provide an early warning of what we can expect the future to hold for the world’s ecosystem.

Global islands monitoring - an initiative presented at the World Conservation Congress 2008