Friday, July 8, 2011

Belly Rubs and Frog Slime: Young Citizen Scientists help study Amphibian Disease in CT

In the past 20 years, a deadly fungal pathogen has decimated amphibian populations on all continents and in all kinds of habitats, ranging from undisturbed rainforest areas to (sub)urban developments. The fungus, Batrachochytridium dendrobatidis (or Bd as it is usually referred to) can cause the deadly disease chytridiomycosis in frogs, toads and salamanders. Some amphibians may act as carriers of the fungus and can be infected without developing the disease, while other species tend to die shortly after becoming infected. The exact mechanism behind this resistance is not well understood yet, but there appears to be a correlation with animal's ability to produce specific peptides in their skin. Initial studies in 2010 by Yale University, Connecticut Audubon Society, the Department of Energy and Environmental Protection and White Memorial Foundation revealed that roughly 30-35% of Connecticut amphibians tested were carriers of the fungus, although no signs of frogs, toads or salamanders dying of the disease were noted.

Many amphibians such as this Spotted Salamander are very secretive and their populations are difficult to monitor. As a result amphibian species have gone extinct before anyone noticed any problems.

As reported previously in this blog and on our website, summer campers, student interns and other field assistants helped CAS Science & Conservation staff to collect amphibians so that we could increase the sample size and geographic coverage of the study. Every frog, toad and salamander caught gets a little 'belly rub' with a toothpick to collect some skin cells, which are later analyzed at a lab at Yale University for the presence of fungal DNA. The animals are then released unharmed back into their natural habitat.

Danielle Breakell (L) from Brown University and Emily Allen (R) from the Kent School volunteer their time and frog catching skills to help CAS Science & Conservation staff survey amphibians in our Croft Preserve in Goshen. Skin swabs from 27 individuals of 6 different species were collected in a few hours.

This year, Connecticut Audubon Society continues its cooperation with Yale University to better understand the status of our native amphibians and to assess whether they are at risk of developing catastrophic population crashes, as has happened in many places worldwide. All field work on CAS sanctuaries now includes attempts to collect skin swabs from local amphibians, and extra efforts are made to gather samples in sanctuaries with particularly good habitat or with known populations of state-listed amphibians.

An additional component to the study of Bd was added this year by Yale University's Hannah Bement and Samantha Attwood who investigate how our native amphibians are protected from the fungus and from developing the disease. In order to do so, they collect skin secretions from amphibians to study their antimicrobial properties. Hannah and Samantha accompanied us to Mondo Ponds in Milford recently to collect samples from frogs that were caught by summer campers from our Milford Point Center. Many hands make light work and there are no better frog-catchers than kids!

Unfortunately, heavy rains in the preceding days had raised the water levels in Mondo Ponds to extreme levels and in spite of our concerted efforts we only managed to catch one single Bullfrog. However, it donated some nice frog slime to the project and will hopefully help Hannah and Samantha with their research. Even though we did not catch many frogs that day, everyone involved learned lots about amphibians in Connecticut, got to participate in some real and important research and most of all had loads of fun!

Hannah Bement (L) and Samantha Attwood (R) from Yale University collect frog slime from a recently captured Bullfrog while explaining the process to summer campers

There will be several more attempts this summer to collect additional frog slime and we are all primed and ready after our first trial run of the season. If you want to help out, please contact our Fairfield center for summer camp schedules in a CAS center near you at (203) 259 6305, extension 109.

Posted by: Twan Leenders, Conservation Biologist.
All photographs Copyright Twan Leenders

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