CHARLES DARWIN RESEARCH STATION NEWS BULLETIN
A hundred years old and still going strong!
While many visitors to the Charles Darwin Research Station (CDRS) seek out the corral housing "Lonesome George", the last tortoise from Pinta Island, most are not aware that one centenarian located nearby has helped to repopulate a whole island of tortoises - and continues to do so today!
In 1977, "Diego" the Espanola tortoise was returned home to Galapagos after having lived in the San Diego Zoo (US) since the 1930's. At the captive breeding centre at the CDRS, Diego joined the last remaining twelve females and two males found on Espanola during the 1960's. The Espanola tortoise population was unnaturally small and the scarce vegetation was further reduced by large herds of introduced goats.
Captive breeding and the eradication of the goats have now rescued the Espanola species. Even though he is probably over 100 years old, Diego, accompanied by his seven female companions, continues to help rebuild his island's population and contributes to their genetic diversity.
"Over 1400 young tortoises have been repatriated and many of Diego's offspring are now breeding in the wild," said Cruz Marquez, CDF herpetologist who has worked with the breeding program for over 25 years.
Diego's compelling success story illustrates how cooperation between international organisations, individuals and government agencies has saved a vulnerable species of tortoises from the brink of extinction. CDF recognises that the future of conservation in Galapagos is built on such team efforts, fueled by a shared vision held by all local and international supporters.
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Darwin's finches: Bigger isn't always better!
In just two decades the medium ground finch (Geospiza fortis) on Daphne Island has evolved, and now has a smaller beak. This is the first time this kind of evolution has been tracked in the wild. The research by long time CDF collaborators and CDF General Assembly members Peter and Rosemary Grant was published in the scientific journal Science in July.
Large ground finches (G. magnirostris) from Santiago Island established a new breeding population on Daphne Island in 1983. During a recent drought they competed with large-beaked G. fortis for big seeds. As a result, G. fortis with small beaks adapted to eating smaller seeds were more likely to survive and breed.
"Once this happened before our eyes, we realised we had a very unusual and potentially very important event to follow," Peter Grant said.
In 2003-2004, the lack of rain meant that seeds of any kind were scarce, and natural selection occurred. Many birds died or disappeared; only small-beaked G. fortis that ate seeds not suitable for G. fortis with larger beaks survived. As beak size is hereditary, this combination of conditions resulted in the evolution of small-beaked G. fortis on Daphne Island and it occurred within just one bird generation.
These new results contribute to CDF's knowledge base about species and ecosystem vulnerability. Internationally renowned scientists like the Grants working with CDF to learn more about the interactions between animals, plants and climatic variations help CDF to advise the GNPS when action is needed to preserve Galapagos' biodiversity and ecosystems.
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Scientists rediscover an amazing plant after 30 years
CDF botanists have rediscovered a leafless plant that had not been recorded in Galapagos for more than 30 years! The parasitic Ombrophytum subterraneum takes nutrients from tree roots and only surfaces when it produces flowers and fruits. It was found by botany staff Xavier Arturo, Freddy Nugra and Felix Burgos who were collecting and cataloging lichens and fungi in the Scalesia forest in the highlands of Santa Cruz Island in August.
The last recording of Ombrophytum was near Cerro Puntudo in the highlands of Santa Cruz Island in 1975 by Dr. Henning Adsersen, a visiting scientist from University of Copenhagen. Further field studies failed to find any specimens, and it was thought that invasive species such as feral pigs might have been eating the fleshy tuber.
"It is the strangest looking plant, something I'd never seen before," said Nugra. Further surveys will be carried out in 2007 to determine the distribution and abundance of this unusual species.
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CDF experts update endangered species lists
When evaluating the vulnerability of unique species found in Galapagos, who better to turn to than the specialist scientific team working with CDF? Scientists use the latest research studies to revise listings in Ecuador's Red Data Book of endangered species maintained by World Conservation Union (IUCN). This information is incorporated into the IUCN Red List of Threatened Species, the most comprehensive inventory of the global conservation status of plant and animal species.
This year CDF entomologists Lazaro Roque and Ana Maria Ortega have evaluated endemic moths (taxonomic Order Lepidoptera) previously not included in the listing. The effects of the introduced cottony cushion scale insect (Icerya purchasi) on the endemic plant Darwiniothamnus tenuifolius has affected the numbers of three Lepidoptera species, including Platyptilia vilema which has been registered as Endangered on the IUCN list. Last year, collaborating scientist Christine Parent recommended that many endemic snails (Bulimulus species) be increased to Critically Endangered and receive immediate conservation attention.
"Timely information is crucial for the protection and restoration of at risk populations," said CDF botanist Alan Tye. Tye chairs the IUCN Galapagos Plant Specialist Group, which is also the Red List Authority. He has recently updated endangered plant species lists for the second edition of the Ecuadorian Plant Red Data Book being published this year. His report showed that many species have suffered severe population declines, including the now critically endangered Rock Purslane (Calandrinia galapagosa).
The impacts from modern pressures affecting Galapagos highlight the need for ongoing vigilance in species monitoring and maintaining current information. This is used to prioritise future restoration activities and advise decision makers about the challenges faced by Galapagos' endangered species.
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