Saturday, October 3, 2009

Frogs Victim of Fungus in RainForest

Approximately three weeks ago, I wrote about a similar fungus that was threatening the frogs of Prince Edward Island, Canada.

It now appears that a fungus is threatening the frogs of the rainforest. Since many of the frogs that are being threatened are present in only one or two populations, once they have become extinct in that area there is no other population to take from for relocation and/or captive breeding programs.

Frog lovers the world over need to make their voices heard. I will have contact info at the end of the blog.

Hemiphractus fasciatus. It carries its eggs on its back. Photo: Roberto Brenes, via Discovery News

A fungus that appears to prefer the rarest species of frog has emerged in the rainforests of Central America. This fungus seems to be deadlier for rare frogs than common ones. This is leading to a homogenization of the local ecosystem causing changes in the local food chain; harming eco-tourism in Central America; and, hindering medical science.

Amphibians — of which frogs make up the majority — are a vital part of the food chain, eating insects that other animals don't touch and connecting the world of aquatic animals to land dwellers. Without amphibians, the insects that would go unchecked would threaten public health and food supplies.

Amphibians also serve important biomedical purposes. Some species produce a chemical used as a pain reliever for humans; one species is linked to a chemical that disables the virus that causes AIDS.

"This frog species, Hylomantis lemur, was a reasonably widespread species, originally present at five study sites. After the fungus passed through the region, it could no longer be found at any site." Photo: Roberto Brenes, via Discovery News

"Everyone knew that amphibian declines were really bad," said ecologist Kevin Smith, of Washington University in St. Louis. "But it looks like its worse than we actually thought."

Smith and colleagues looked for patterns of extinction in frogs from eight rainforest sites around Costa Rica and Panama. They compiled several years’ worth of data from previous studies, in which scientists had painstakingly surveyed frog diversity both before and after the arrival of Batrachochytrium dendrobatidis (Bd).

Bd has swept through amphibian populations globally in the last decade, often decimating populations. In Central America, Smith said, infections can wipe out half of the species at a given site.

The chytrid fungus coats the frog's skin and makes its pores non-functional. Because a frog relies on its porous skin for hydration and for some of its respiration, the fungus essentially cuts off its water supply and makes it difficult to breathe. In the end, the frog dies from dehydration.

It is not yet clear why the rare frogs are succumbing more frequently than the more common varieties; however, as they disappear so do the roles they fill in the ecosystem.

Tom Rooney, an ecologist at Wright State University in Dayton, Ohio, says that the loss of variety makes it increasingly hard for the species left behind to deal with further environmental damage.

"If you're thinking globally, studies like this are telling us that losing rare species is not a local phenomenon," Rooney said. "If they are disappearing locally, there's a good chance they're disappearing regionally, and local efforts can be even more important."

A CBCtv video discussing the danger the frogs of the world are in:

Sir David Attenborough discusses why frogs and amphibians are so important to any ecosystem.

Contact info for places that support frogs.
The Bronx Zoo
Frog Watch USA - currently under upgrade
Adopt a Pond

and you can always contact your government official to demand that issue receive the attention it deserves!

Via Discovery News and TreeHugger

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