LOOKING for a sound investment to combat the biodiversity crisis? Spend your cash on an island. It turns out they are about nine times as valuable as an equally large piece of mainland. So says the first worldwide analysis of the importance of different regions for maintaining global biodiversity.
While it is common knowledge that islands generally house ahigh number of species that live only in that location, the total diversity of life on most islands is relatively low compared with mainland areas. As a result, their importance for conservation efforts hasn鈥檛 been clear, says a team from the Universities of and , Germany, and the .
To settle this question, they calculated a new combined index which takes into account both the number of unique species in a given region and the total number of different species living there. This 鈥渆ndemism richness鈥� scale measures how much a given area of land contributes to global biodiversity. The team evaluated the endemism richness of plants and vertebrate land animals for 90 regions covering most of the Earth鈥檚 surface. They discovered that values for islands were 9.5 times higher for plants and 8.1 times higher for vertebrates, compared with similarly sized regions of mainland (Proceedings of the National Academy of Sciences, ). Tropical islands scored highest, with New Caledonia topping the list.
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鈥淭he results should lead to an increased investment in conservation on tropical island biodiversity hotspots,鈥� says Thomas Brooks, head of Conservation Priorities and Responses at in Arlington, Virginia.
鈥淭he results should lead to increased investment in conserving tropical island biodiversity hotspots鈥�
To some extent, this is already happening. For example, the , run partly by Conservation International, is in the process of preparing a multimillion dollar investment in the Caribbean islands.
Increased investment in islands should be doubly worthwhile because they are likely to lose more habitat from human impact this century than mainland regions, say the researchers.
