Many endangered species stranded outside protected areas, study finds

Posted: 2 November 2006

Author: James Randerson

The most comprehensive map of endangered species and where they live has shown that 11 per cent of birds, 24 per cent of mammals and 33 per cent of amphibians are at risk.

  • Challenge to 'hotspot' theory of conservation
  • At-risk animals more spread out than thought

But worryingly for conservationists, the map suggests that threatened species are not clustered together, making it harder to target resources. So the current "silver bullet" approach to conservation - which relies on protecting areas such as national parks which contain numerous threatened species - is missing many endangered animals.

Critically Endangered Iberian Lynx. Photo: IUCN/P. Jackson
Critically Endangered Iberian Lynx. Photo: IUCN/P. Jackson
The Iberian Lynx (Lynx pardinus) is the world's most threatened felid species. It is endemic to Spain and Portugal, and currently categorised by IUCN as Critically Endangered(CR) as a result of the fragmentation of its natural habitat by agricultural and industrial development. © IUCN/P. Jackson
"In the past what we have essentially done is identify plots using one particular [group of organisms] and said, 'Right, this is where we should put our protected areas'," said Andrew Pullin, head of the Centre for Evidence Based Conservation at Birmingham University. "We may have put our protected areas in great places for mammals or birds but we may not have adequately covered areas that are hotspots for lesser-known groups."

A guiding principle in conservation is the notion of "biodiversity hotspots". The idea was the brainchild of the British ecologist Norman Myers, who in 1988 identified parts of the planet that were both threatened by human activity and contained large numbers of endemic species.

The charity Conservation International refined the concept in the 1990s to single out 25 hotspots including the Congo basin in central Africa, the Mediterranean and the Amazon. The idea was that limited funds should be applied where they would make the most difference. But that only works if lots of different endangered species tend to be clustered in the same places - an assumption implicit in the hotspot approach.

'Red list'

The Blue Poison Frog (Dendrobates azureus) is listed as Vulnerable. Photo: Russell Mittermeier
The Blue Poison Frog (Dendrobates azureus) is listed as Vulnerable. Photo: Russell Mittermeier
The Blue Poison Frog (Dendrobates azureus) is listed as Vulnerable because of its highly restricted range. This frog is known only from the type locality on Vier Gebroeders Mountain, Suriname. It is not significantly threatened in its tiny range, but fire probably has an impact on its forest habitat. Illegal collection of the species for the international pet trade probably no longer has a significant impact, since the species is extensively bred in captivity.© Russ Mittermeier
To test whether this is true, Ian Owens at Imperial College London and his team collected information on the rarity of every known species of bird, amphibian and mammal from the World Conservation Union's "Red List" of endangered species. They combined this with painstaking observations in the wild of all 19,349 species. They have presented the information as global maps of extinction risk for the three groups.

"That's the guts of this study," said co-author David Orme. "You couldn't do it unless someone had gone to the trouble of putting together range maps for all the amphibians, mammals and birds."

Unexpectedly, the maps of threatened species did not match up, the team report in the current issue of Nature. "The fact that [threatened species] are not cropping up in the same places is worrying ... Simply picking the most species-rich areas doesn't necessarily catch everything you want to."

Dr Orme singled out Papua New Guinea as an area not included as a traditional hotspot, but a place the analysis picks out as having numerous endangered species - such as the McGregor's bird of paradise, long-nosed echidna and Goodfellow's tree kangaroo.

On the other hand two places - the Mediterranean and the Cape region of South Africa - which are traditional hotspots were not picked out by the study.

Professor Owens said the patterns arose because different animal groups were susceptible to different threats. "Endangered bird species are often at risk because their habitats are being destroyed. However, different factors entirely may affect mammals such as tigers, which are under threat from poachers, and amphibians, which are being diminished by diseases brought into their habitat by non-native fish.

"It's really important not to assume that there are simply a number of hotspots across the globe where everything living there is endangered - the picture is far more complicated."

Dr Orme acknowledged that translating the theory into conservation practice will be very difficult. "So much of the conservation on the ground comes down to politics and economics," he said.

James Randerson is science correspondent for The Guardian.

logo Guardian Unlimited © Guardian News and Media Limited 2006. This article was first published by The Guardian, (Thursday November 2, 2006). All rights reserved. Reproduced with kind permission.

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