Birdwatch News Archive
Kosrae Crake was a species found only on its island namesake in the Caroline Ilsands of the south-west Pacific Ocean; this is a painting of the two only known specimens. Image: Julian P Hume.
Rate of bird extinctions accelerates
Posted on: 09 Oct 2012
The rate of extinction of the world's bird forms is speeding up at an alarming rate according to new research from BirdLife International.
A new collaborative study with and Charles Darwin University published in the online scientific journal PLoS One reveals 279 bird species and subspecies from across the globe have become extinct in the last 500 years. The study shows that species extinctions peaked in the early 20th Century, then fell until the mid-20th Century, but have subsequently accelerated.
In David Callahan's recent magazine feature on bird extinctions (see Birdwatch 240: 25-28), he used a timeline to illustrated the extirpation acceleration as derived from the new title Extinct Birds by Julian P Hume and Michael Walters, which has a comprehensive list of all the species known to have died out since around 1300 AD. However, the new study adds further more subtle analysis to show that, after a small lull, extinctions are picking up again.
As many other authorities have concluded, most bird extinctions are indeed on the major Pacific island groups, including Australasia, and show a small lull in the middle of the 20th Century. However, when subspecies are included in analyses, the rate of extinction has indeed sped up. as we waver as to the precise definition of what a species is, this shows a definite loss of biodiversity, that of discrete and diagnosable bird forms that are gone forever.
“Until this study it had been hoped the rate of extinction was slowing”, said lead author Dr Judit Szabo of Charles Darwin University. “Historically most extinctions have occurred on islands, particularly those in the Pacific, but most of the really susceptible species are long gone.”
The study shows that the destruction of native habitat for agriculture is currently the main cause of extinctions. Unsustainable hunting and the introduction of alien species such as cats and rats have been the main causes of extinctions in the past. “Humans are directly or indirectly responsible for this loss”, Dr Szabo said.
The world’s nations had agreed through the Convention on Biological Diversity (CBD) to slow biodiversity loss by 2010, but having failed to reach this goal, the target has now been adjusted to 2020. Report co-author Dr Stuart Butchart, BirdLife International’s Global Research Co-ordinator, said many species survive only because of conservation interventions. “This list would have been much longer were it not for the work being done around the world to stop extinctions, but we need to scale up our efforts substantially to avoid further human-induced extinctions”, he said.
“Our analysis provides the most detailed picture to date of recent extinctions and will help us identify strategies to tackle the loss of biodiversity and halt future human-induced extinctions. The Conference of the Parties of the CBD that starts today in Hyderabad, India will need some firm action to achieve its target of achieving this by 2020.”
Szabo, J K, Khwaja, N, Garnett, S T and Butchart, S H M. 2012. Global Patterns and Drivers of Avian Extinctions at the Species and Subspecies Level. PLOSONE 7: e47080.
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