Breeding success in fight to save mountain chickens
An emergency rescue operation to save the critically endangered mountain chicken frog from certain extinction has had a major breakthrough with the birth of four batches of tadpoles at Durrell Wildlife Conservation Trust and Parken Zoo.
Conservationists at Durrell are also delighted to have captured high quality film footage of the female frogs caring for their young, giving an invaluable insight into the behaviour of this species. The births at the two institutions follow a rescue mission earlier this year, during which 50 individuals were taken from the Caribbean island of Montserrat following the outbreak of a deadly fungal disease, Chytridiomycosis. These tadpoles are now the best hope of saving this species on the island.
The mountain chicken frog Leptodactylus fallax is one of the largest frogs in the world, but it has also become one of the most threatened. Thought to have once occurred on seven Caribbean islands, it is now restricted to Montserrat and Dominica. However, the arrival of chytrid fungus all but wiped out the population on Dominica and since February this year has caused major declines in Montserrat pushing this species to the brink of extinction.
Durrell Wildlife Conservation Trust has worked with mountain chickens in Montserrat and in captivity for ten years. As soon as dead frogs were discovered by the Montserrat Department of Environment, Durrell sent a team of herpetological and veterinary experts to the island to survey the extent of the disease and train local forestry staff in bio-security techniques to limit the spread of the disease. A cause for hope came with the discovery of an apparently healthy population that had remained isolated in one of the most important sites for the frog, a location in a mountainous area, called Fairy Walk.
A recovery programme was quickly set up and 50 frogs were brought into captivity to breed and ensure the long term survival of the species. Twelve frogs came to Durrell’s headquarters in Jersey, 12 went to London Zoo and 26 to Parken Zoo in Eskilstuna, Sweden. All frogs are kept in strict bio-secure conditions to minimise any risk of disease transmission either to or from these animals. The challenge for each of the institutions holding the animals was to get them to reproduce, as they are notoriously difficult to breed because of the intense parental care behaviour. Although there are mountain chickens in more than 20 institutions worldwide, only Durrell has managed to breed them regularly in Europe since 1999.
These four batches could result in over 100 frogs available within the first generation born from the rescued population. Dr. Gerardo García, Durrell’s Head of Herpetology, says this is extremely exciting; “Not only have we been able to start breeding the frogs within the first six months of the rescue operation but we were also able to watch and film the females feeding unfertilised eggs to their tadpoles. It is normally such a private and secretive moment that we never thought we would be able to capture it with such clarity. These are incredible images that show us a new facet of their behaviour as we race to save them from extinction.” - Watch Video
The goal of the captive breeding programme is to build up a large number of frogs that can be introduced back into Montserrat to chytrid free areas of the island within the next two years. The birth of these four batches is an important step towards this goal.
Through the collaborative efforts of Durrell, Parken Zoo and the Zoological Society of London the restoration of this species looks promising by studying the spread of the fungus in the wild, how it may be controlled and then how animals can be placed in safe locations on the island.
Helena Olsson, Zoo Director of Parken Zoo was very excited when the nests were confirmed fertile, “I have been working closely with colleagues in Jersey to create the conditions that would best replicate the situation in the wild and get the animals breeding. We used modeller’s clay to build nest burrows that would suit the frogs and it seems to have worked. Our huge commitment to this programme has bourn fruit and we’re proud to be part of the effort to reverse the fortunes of this species”.
Amphibian chytridiomycosis was first discovered in 1998, when it was found to be the main cause of amphibian declines in the rain forests of Australia and Central America. Since then, this disease has been associated with amphibian declines and extinctions in many countries. Indeed, it has been found to be an emerging threat to > 300 species (of frog, toad, newt and salamander) representing at least 14 amphibian families across 6 continents. In Dominica, which is the other island with mountain chickens, chytrid first emerged in 2002 when large numbers were reported to be dead or dying. The disease quickly spread across the island and the mountain chicken population declined by approximately 80% within two years of the first confirmed cases.
The mountain chicken recovery programme
A Species Action Plan (SAP) is a scientifically authoritative, strategic document that defines specific, measurable objectives and actions for conserving priority species. The SAP for the Mountain Chicken in Montserrat was developed at a participatory workshop, held in October 2007 in Montserrat. The Plan’s Vision is of “a thriving, sustainably managed population of mountain chickens generating pride in Montserrat’s natural and cultural heritage for present and future generations.” Its aim is to bring about “a measurable increase in the security of the mountain chicken population on Montserrat” over the next five years. Due to the outbreak of the chytrid fungus in Montserrat early this year a Recovery Programme is being developed to stop the accelerated process of extinction of the wild populations in the island and their revival through an intensive captive breeding and reintroduction programme.
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Posted 12 August 2009