Conservation targeting called into question

Ecologists may need to reconsider methods of targeting conservation effort in species rich biodiversity hotspots such as rainforests, according to scientists in the journal Nature, 18 August 2005.

A consortium of scientists, funded by the Natural Environment Research Council (NERC), has produced the first global database of bird biodiversity. Their analyses show that hotspots of diversity in species richness, rarity and threat occur in widely differing geographical areas and that there is surprisingly little overlap between these patterns.

Co-author Ian Owens from NERC‘s Centre for Population Biology, Imperial College London, who worked on the global database said: ‘This is the first time anyone has put together a detailed map of bird biodiversity on a global scale. What interested us is that this map shows biodiversity patterns are more complicated than we originally thought.

‘Different aspects of biodiversity such as rarity and extinction risk show very different geographical distributions, so they are probably produced by different mechanisms and will probably need different sorts of conservation effort,’ added Professor Owens.

According to co-author David Orme, also at Imperial, the study is a major advance in knowledge: ‘biodiversity hotspots have a high profile in conservation, but are controversial because their underlying assumptions remain untested. The key assumption is that ‘hot’ areas for one aspect of diversity will also be hot for other aspects. Our analyses show this is not the case: we found different types of hotspot in different areas.

‘For birds, hotspots of species richness are the mountains of South America and Africa, whereas hotspots of extinction risk are on the islands of Madagascar, New Zealand and the Philippines. Different mechanisms are therefore responsible for different aspects of biodiversity, and conservation strategy needs to be based on multiple factors,’ added Dr Orme.