For many years now, chytrid fungus has been devastating amphibian populations around the world, and caused the extinction of some species. Global concern has grown as more species head towards extinction, particularly in the tropics, but also in temperate latitudes. An ongoing research project conducted by the Institute of Zoology, London, is receiving fresh impetus this year with the employment of researcher Freya Smith to examine the spread of chytrid in the UK, and on the possibility of our amphibians being adversely affected by it.
A UK survey in 2008 involved swabbing of amphibians at over 100 breeding ponds. This found 19 sites positive for chytrid, although the effects on the amphibian populations are unknown. The advice being given by advisory bodies is to engage in biosecurity, especially if working in or around ponds. Many ecologists have already been disinfecting nets and boots between ponds for the last two years, and the ARG UK network (www.arguk.org) has issued a guidance note. Hand-held bleach sprays are effective, and easy to obtain from supermarkets.
Freya says her work at the IoZ will involve a more in-depth analysis of the 2008 results, and a comparison between positive and negative sites. "This season, survey work will focus on a subset of sites which were found to be positive for chytrid in the 2008. These sites will be visited on five separate occasions throughout the year, to allow us to collect temporal data and to help determine within-site prevalence."
A second nationwide chytrid survey will take place in 2011, probably resampling many 2008 sites, as well as increasing coverage in under-represented areas such as Scotland, the South West, and Northern Ireland. The results will advise government policy (Defra is funding the 2011 survey).
Freya continues: "We do not yet know what impact, if any, this pathogen is likely to have on UK wildlife. The 2008 survey revealed that [chytrid]is already widely distributed. It is likely that additional sites, other than those known to be positive from sampling in 2008, are also harbouring the infection. It is therefore prudent to adhere to strict biosecurity precautions over the coming field season."
Updated Bd biosecurity guidelines are in the pipeline but for the time being, the best advice can be found at http://static.zsl.org/files/biosecurity-arguk4-511.PDF.
As a recent convert to herpetology, Freya says, "I feel very privileged to have the opportunity to work with such a knowledgeable and dedicated network of people. Coming from a veterinary background, herpetology is a whole new world for me but I seem to be very rapidly falling under its spell…."