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Brown Bag 4/10/13

April 21, 2013

The brown bag lecture on 4/10/2013 by Mason Ryan was titled “On the Trail of Missing Frogs: searching for Lost Specimens in an Age of Extinction”. This was my favorite talk so far. Mason was very passionate about his work and had many beautiful pictures with interesting descriptions of the frogs, their habitats and lifestyles, and their endangered status.
He said that it is rare to find a dead frog in the wild, but when he went collecting he found many just laying around and decomposing due to local and global die off caused by the Chytrid fungus. Chytrid can cause a loss of 80% of a species within 90 days of infection, some may rebound taking four or more years but those will lose at least 50% diversity. Chytrid is able to persist in environments and frogs have non random susceptibilities. It can persist in both degraded and pristine habitats.

Since 1980 over 100 frog species have gone extinct, and there are 168 total species that we know of that are extinct. However, this number is likely very low because species that can’t be found are often classified as “unknown” rather than extinct. 32% of frog species are extinct, critically endangered, endangered, or vulnerable. 24.5% have an unknown status, and 43% are in population decline. It is estimated that 75%-97% of amphibian species are threatened with disease. The most threatened are usually medium sized bodied with increased aquatic association living at greater than 500m elevation, but Chytrid effects all orders and families.

Even if we capture endangered species and put them in zoos there are many that we don’t have life history information about, this can be problematic because we don’t know how to get them to breed. Another problem with captivity is that a cap has been put on the number of species that can be focused on, this cap is 6; there are 7116 known species.

Mason suggested that if we search for “missing” species and populations it will be very cheap, about $8,000 per year per region, we can improve conservation statuses of many species by simply finding them. A downside to this approach is that its possible we may not find any frogs. Mason defined missing as a historically abundant species that hasn’t been detected for seven or more years despite persistent survey effort because previous definitions had been vague. He suggests searching for historically abundant species because this abundance gives a larger possibility that the frogs will be found if they are still alive. Some missing species have started to come back into existence (we don’t know how), so Mr. Ryan is hoping that the species may disappear together and come back together.

He hypothesizes that perhaps there will be national recovery because Chytrid is either becoming less virulent due to hyper success or frog immunity is increasing.


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