Increasing numbers of birds, mammals and amphibians have moved closer to extinction in the last several decades—but not as far as they would have if no conservation measures had been enacted, researchers report in ScienceExpress this week.
The paper was published in conjunction with the 10th Conference of the Parties to the Convention on Biological Diversity in Nagoya, Japan, where world leaders are discussing the failure to meet the convention’s targets for 2010 and negotiating a revised plan for tackling biodiversity loss and new targets for 2020.
To assess the status of the world’s vertebrates, Michael Hoffmann of the International Union for the Conservation of Nature (IUCN) and a large, international team of coauthors analyzed data for over 25,000 vertebrate species categorized on the IUCN Red List of Threatened Species.
“We document just how severe the situation is for vertebrates, the species of greatest interest to people, but we also show that the situation is not futile and that the loss of populations and species along with the benefits we accrue from them can be halted and reversed,” said co-author Stuart Butchart of BirdLife International.
Global patterns of threat, for land (terrestrial and freshwater, in brown) and marine (in blue) vertebrates, based on the number of globally threatened species in total. | Image courtesy of Science/AAAS
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The scientists report that one-fifth of species is classified as threatened, and this figure is increasing. On average, 52 species of mammal, birds and amphibian move one category closer to extinction each year.
The tropics, especially Southeast Asia, are home to the highest concentrations of threatened animals, and the situation for amphibians is particularly serious. Most declines are reversible, but in 16% of cases they have led to extinction.
The researchers also asked whether conservation efforts such as establishing protected areas and adopting national legislation have made any measurable contribution to preserving biodiversity. By looking at species whose conservation status has improved in response to some type of conservation measure, Hoffmann and colleagues estimate that overall declines would have been approximately 18% worse without any conservation actions.
“And hence, even though as we’ve been hearing the Convention on Biological Diversity‘s target for 2010 hasn’t been met, this work provides good evidence that conservation actions can work and that if stepped up there is still realistic hopes of reducing some of the drivers of the biodiversity decline,” said Andrew Sugden, deputy and international managing editor at Science.
A set of projections in an accompanying Review article also forecasts biodiversity declines during the 21st century, but with a wide range of possible outcomes. This broad range arises because we have significant opportunities to intervene through better policies, and because scientific projections include large uncertainties, which is an urgent problem in itself, according to Henrique Pereira of Universidade de Lisboa, Portugal, and coauthors.
The International Union for Conservation of Nature, with the cooperation of AAAS/Science, organized a news conference on the new research in Nagoya, in conjunction with the Convention on Biodiversity meeting. An international news teleconference was organized by AAAS/Science in cooperation with IUCN.
Read the abstract for “The Impact of Conservation on the Status of the World’s Vertebrates.”
Read the accompanying Review article, “Scenarios for Global Biodiversity in the 21st Century.”