Celebrating island biodiversity

Abstract

The conservation of biodiversity on small islands is fraught with challenges, most of which do not apply to mainland areas and which have characteristics unique to islands. Ever since the publication in the 1960s of the theory of island biogeography by McArthur and Wilson, biodiversity assets on islands have received increasing attention. The global island human population is estimated to constitute about 10 per cent of the world’s population, with 169 islands having a population of over 100,000, of which 15 have a population of over a million. In Europe alone, there are around 500 islands larger than 20 km2, which add up to more than 70,000 km2. This is equivalent to seven per cent of the total surface of Europe. Small islands cover just five per cent of the global land area; yet around a third of world’s threatened mammals, birds and amphibians are found only on islands. Not surprisingly, islands represent between a quarter and a half of all biodiversity conservation priorities, depending on the measure used.