Thursday, 31 January 2008

New Bd ecology paper

A new paper from Bosch & Rincon, on the first evidence of an indirect effect of chytridiomycosis in the field, is in press in Diversity and Distributions. We have documented how the disease may indirectly influence community structure by altering biotic interactions in which affected species participate. In PeƱalara Natural Park (Central Spain), the common toad (Bufo bufo) has significantly increased its number of breeding sites after chytridiomycosis nearly extirpated the midwife toad (Alytes obstetricans). An experiment demonstrated that breeding B. bufo adults strongly avoided laying eggs in water containing A. obstetricans tadpoles, accounting for observed patterns of pond use. Bufo bufo is far less severely affected by Bd, spends less time in the water and has higher fecundity than A. obstetricans. So, inter-specific differences in the severity of the effects of the pathogen may modify their biotic interaction indirectly favouring one of them.
We think this kind of indirect effect may be a relatively frequent consequence of chytridiomycosis, and further attention must be paid to this to fully understand the deep effects of the disease on amphibian communities.

Wednesday, 23 January 2008

Welcome to EDGE-Amphibians!

The Zoological Society of London (ZSL) has launched a major conservation program that is focused on drawing attention to the plight of amphibians. EDGE (Evolutionarily Distinct and Globally Endangered) has at its core the aim of identifying the planets most endangered species based on phylogenetic, as well as more conventional, conservation criteria. EDGE species are in cases the last surviving members of groups that have had long evolutionary histories, yet they 'are unfamiliar to both conservationists and the public, and are frequently overlooked by current conservation initiatives'. EDGE Amphibians has identified a list of Top 100 endangered species, for which extinction would represent a disproportionate loss of the worlds amphibian biodiversity. And, surprise surprise, a number of these species are at risk from chytridiomycosis. Infection by Bd is implicitly recognised in the EDGE site as a major driver of declines, and EDGE provide information on the major amphibian diseases in the Conservation section of their website. Well done EDGE and good luck!

Following is a short movie where The EDGE's own Helen Meredith explains more about EDGE Amphibians.

Tuesday, 8 January 2008

Happy New Year in the Year of the Frog

Welcome to 2008, the year the Amphibian Ark has tasked to be the Year of the Frog (Click here to visit site ) in an effort to raise awareness of the AArk’s lead role in coordinating public awareness and global captive breeding programmes for species at greatest risk of extinction. Of course, many of those species are at risk due to chytridiomycosis, not least of which is the Mt Chicken frog, Leptodactylus fallax, a species nearly eradicated from Dominica by the emergence of Bd. The frog is found also on Montserrat, where the species range was severely impacted by volcanic activity in the 90s, but where Bd appears not to have yet reached (see Garcia et al. 2007 Oryx 41(3):398-401). On Dominica, chytridiomycosis was first reported in L. fallax in December of 2002 and in less than 1.5 years Dominican Mt. Chicken frogs declined by an estimated 70% (Malhotra et al. 2007 Applied Herpetology 4:177-194), with current estimates at 8,000 individuals: the IUCN currently lists the species as Critically Endangered. The Zoological Society of London has established a small captive population for the purposes of captive breeding (Click here to read article) and the herpetology staff of ZSL London Zoo is currently battling Bd infection in this population with Itraconazole. Results so far are extremely encouraging: previously diseased males appear healthy, test negative for infection and are starting to exhibit secondary sexual characteristics.

Animal Conservation published in the last issue of 2007 a featured paper by Doug Woodhams and coauthors (Woodhams et al 2007 Animal Conservation 10:409-417), along with commentaries and a reply by the authors of the original paper. The featured paper describes the latest in a series of papers examining the relationship between amphibian species, the production of antimicrobial peptides and susceptibility to chytridiomycosis. Another recent publication by Seimon and co (Seimon et al 2007 Global Change Biology 13:288-299) provides evidence that dispersing amphibians bring Bd along with them. Furthermore, the dispersers are taking advantage of recently available habitat made available through climate change.

2008 Year of the Frog is here!

This year is going to be a busy one, and a major global focus is going to be raising awareness of the causes and effects of the amphibian extinction crisis. The Patron of AArk, Sir David Attenborough, has kicked off the year with an impassioned plea; "Today, amphibians can be found in enormous variety and occupy a wide range of water and land habitats, except for the oceans and the frozen polar regions. They are so familiar to most people that they have become part of the myths, legends, and folk tales of many cultures. Yet their habitats are being destroyed at such a speed that now many species may disappear before we even discover that they exist. Infections of chytrid fungus, for which there is no known cure, are today spreading rapidly and threatening entire species. There is thus the real possibility that much of an entire category of animals may become extinct unless we prepare to act quickly." [link] I feel that this is a good rallying call, and despite the gloom there is much to be positive about. That AArk is occurring at all is testament to the commitment of the conservation and scientific community to address the problems facing amphibians. Lets belive that 2008 will be the year that Science and Policy weld together to address the amphibian crisis. Stay tuned to this blog for further news, synthesis, treatment protocols and the launch of the Global Bd Mapping Project.