Mauritius kestrel reveals genetic secrets

THE MAURITIUS KESTREL REVEALS ITS GENETIC SECRETS TO CONSERVATIONISTS
Heralded as the world's rarest bird in 1974, with only a single breeding pair in the wild, the Mauritius kestrel was rescued from extinction by one of the most successful wildlife conservation and captive breeding programmes.

Following habitat destruction and pesticide contamination of a historically pristine island, the plight of this raptor stimulated an intensive conservation programme, using captive breeding and re-introduction, which was co-ordinated by the Mauritian Wildlife Foundation, the Peregrine Fund and the Durrell Wildlife Conservation Trust. The Mauritius kestrel has made a dramatic recovery and has been restored to over 250 wild pairs.

In a paper published today, 10 February 2000, in Nature, a team of scientists, from the Zoological Society of London, the Mauritian Wildlife Foundation and Queen Mary and Westfield College, has studied the genetic history of the Mauritius kestrel. DNA samples from the current population of Mauritius kestrels were analysed, and their genetic diversity was compared with that of museum specimens, some of which could be dated at 170 years old, that were collected before the 'population bottleneck' in 1974.

"We were surprised to find that pre-bottleneck genetic variation was remarkably high and was comparable with the levels of genetic diversity in widespread kestrels found on the African mainland" comments Jim Groombridge of The Zoological Society of London. "It is encouraging that despite the dramatic loss of genetic variation, the Mauritius kestrel seems to be thriving"

Contrary to assumptions that island species have always had comparatively low genetic diversity, their findings show that the Mauritius kestrel had surprisingly high genetic diversity prior to the 1974 population crash. This discovery sheds new light on the kestrel's success story, and offers hope to other critically rare island-dwellers.

Genetic studies of many endemic island populations which currently survive today show low variation within their DNA. Whether or not this has historically always been the case has remained unclear, and man's recent and widespread destruction of island species has made an accurate assessment even more difficult for conservationists. The well-documented history of the Mauritius kestrel, and the success of the conservation project provided scientists with the ideal opportunity to examine the genetic consequences of a population bottleneck on an endemic island species.

Low genetic diversity is often thought to limit the adaptability of a population, yet the restored kestrel has begun to exploit gardens and other habitats created by humans. Richard Nichols of Queen Mary & Westfield College, London finds it encouraging that "endangered and genetically impoverished species show surprising ecological flexibility".

The scientist's genetic results imply that other endemic island species may also have suffered recent genetic loss following undetected population crises associated with man's widespread destruction of delicate island ecosystems. Although this conclusion may be an alarming prospect for conservationists, the successful recovery of the Mauritius kestrel is highly encouraging.

Note to Editors

Authors:
Jim J. Groombridge
Institute of Zoology
Zoological Society of London
Regent's Park, London NW1 4RY

Carl G. Jones
Durrell Wildlife Conservation Trust
Jersey, Channel Islands

Michael W. Bruford
Cardiff School of Biosciences
Cardiff University
Cathys Park, Cardiff, CF1 3TL, UK

Richard A. Nichols
School of Biological Sciences
Queen Mary & Westfield College, London E1 4NS
020 7882 3074
(Delia Ray, Head of Press and Publications)

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