Chytrid Fungus Infection & El Nino May Have Killed Golden Toad, Not Climate Breakdown - AFP

[hatrack]

Scientists broadly agree that global warming may threaten the survival of many plant and animal species; but global warming did not kill the Monteverde golden toad, an often cited example of climate-triggered extinction, says a new study. The toad vanished from Costa Rica's Pacific coastal-mountain cloud forest in the late 1980s, the apparent victim of a pathogen outbreak that has wiped out dozens of other amphibians
in the Americas.

Many researchers have linked outbreaks of the deadly chytrid fungus to climate change, but the new study asserts that the weather patterns, at Monteverde at least, were not out of the ordinary. The role that climate change played in the toad's demise has been fiercely debated in recent years. The new paper, in the March 1 issue of the Proceedings of the National Academy of Sciences, is the latest to weigh in. In the study, researchers used old-growth trees from the Monteverde Cloud Forest Reserve to reconstruct moisture levels in that region over the last century.

They expected to see global warming manifested in the form of a long-term warming or drying trend, but instead discovered that the forest's dry spells closely tracked El Nino, the periodic and natural warming of waters off South America that brings drought to some places and added rainfall and snow to others.

The golden toad vanished after an exceptionally dry season following the 1986-1987 El Nino, probably not long after the chytrid fungus was introduced. Scientists speculate that dry conditions caused the toads to congregate in a small number of puddles to reproduce, prompting the disease to spread rapidly. Some have linked the dry spell to global warming, arguing that warmer temperatures allowed the chytrid pathogen to flourish and weakened the toad's defenses.

EDIT

http://www.terradaily.com/reports/El_Nino_And_Pathogen_Killed_Costa_Rican_Toad_999.html

[kestrel91316]

1. I always assumed that the range of fungi and other organisms was changing

because of climate change, and I also think the nature of El Nino has changed because of same. Remember, this frog evolved in an area where El Nino has presumably always existed.

I don't see how alteration of ecosystems due to climate change CAN'T lead to this exact situation.

[hatrack]

2. Yes, but that's not how tool-monkeys LIKE their causality!

Colonel Mustard in the conservatory with the candlestick - infinitely preferable.

[RaleighNCDUer]

3. The question then is, Why didn't El Nino wipe them out before, under

the same conditions?