.jpg) Risk Assessment of Chytridiomycosis to European amphibian biodiversity
Coordinator: Dr. Matthew Fisher
Participating countries: UK, FR, DE, ES
Link to presentation
News item (released 25 January 2010)
 Europe's Amphibians are disappearing:
18 of 81 species are experiencing some degree of extinction threat and even widespread species are disappearing from large portions of their ranges. We have found that a newly emerged infectious pathogen, Batrachochytrium dendrobatidis, a previously undiagnosed threat to Europe’s amphibians, is infecting over a third of European amphibian species and at least 10% of our amphibians are dying in the wild from the disease, chytridiomycosis. Nevertheless the extent that this invasive infectious disease is impacting on amphibian biodiversity is almost completely unrecognised by European conservation agencies, governments and academic institutions. To address this lack of knowledge RACE will assess the risk that chytridiomycosis poses to European amphibians and will implement the first pan-European attempt to mitigate disease. Using field-data on the prevalence, intensity and timing of infection/mortalities, spatial-genetic information will be used to identify the timing, and frequency, of B. dendrobatidis introduction(s) into Europe, as well as assessing the differential virulence of genotypes. These spatial and genetic data will be used to parameterise mathematical models focused on defining the principle drivers of chytridiomycosis including identifying the importance of introduced non-native amphibian species in vectoring spread of the disease into Europe. The environmental envelope associated with chytridiomycosis will be identified and projected using current models of climate change in order to assess future risk. Where appropriate, ex situ captive breeding programs may be recommended for highly at-risk species, and in tandem we will be developing antifungal based therapies to treat infected populations.
The hazard that the international trade in Amphibians poses to wild populations
The global trade in amphibians is substantial, involving hundreds of species and occurring on every continent where amphibians occur. Many of these widely-traded species are known to vector Batrachochytrium dendrobatidis and several have established themselves as invasive non-native species: principle culprits are the African clawed frog Xenopus laevis, the North American Bullfrog Rana catesbeiana and the Cane toad Bufo marinus. It is now clear that these amphibian ‘Typhoid Marys’ have led to the importation of Batrachochytrium into naïve regions of the globe, and bullfrogs are known to have led to outbreaks of the pathogen in Europe. As a first means to controlling the international trade in infected amphibians, the amphibian pathogens B. dendrobatidis and ranavirus have been listed as notifiable pathogens by the World Organisation for Animal Health (the OIE). This means that animals that are imported from a disease-endemic region now need to be certified as free from infection prior to importation.
However, for many parts of Europe, this legislation comes too late as infected populations of invasive amphibian species have already become widely established.
Desired Outcome:
RACE aims to train and mentor the development of new national chytridiomycosis-surveillance efforts, and collborators involvement in RACE will be used to leverage region-specific funding from government and non-governmental organisations. In this manner RACE will develop approaches to understanding where in situ and captive-breeding conservation efforts are most necessary to mitigate the effects of chytridiomycosis and to preserve amphibian biodiversity; these approaches will be formalised into a European Threat Abatement Plan (ETAP). Implementation and use of the outputs of RACE will be used to advise policy on an international level by involving partners in other EU-projects and the United Nations Environment Programmes 2010 biodiversity targets. Our overarching goal is to identify and prioritise conservation efforts in the light of this novel and devastating panzootic disease.
Photos:
Midwife toad and Common Toad mortalities resulting from chytridiomycosis (Matthew Fisher)
The Chytrid, Batrachochytrium dendrobatidis (Louise Walker & Neil Gow, Aberdeen)
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