is not always the driving force behind extinctions. In a 2006 study tropical warming of the last decade was linked to the disappearance of 64 amphibian species. The climate change created conditions that allowed the cychrid fungus to grow and spread, which led to the lethal disease of frogs and toads, the researchers said. A recent study argues that it was the periodic and natural warming of waters off South America, El Niño, in combination with the recently introduced cychrid fungus that led to the extinction of the Monteverde golden toad in 1986 – 87.
This extinction is often cited as an example of climate-triggered extinction. Using new techniques to reconstruct past climate from tiny samples of wood drilled from tropical trees, the researchers of Columbia University and University of Maryland discovered that the dry spell of 1986 – 87 was within the range of normal climate variability. So, it had nothing to do with global warming that the Monteverde golden toad went extinct. It was just bad luck. A dry spell caused by El Niño, not long after the deadly cychrid fungus was introduced, made the toads huddle together for reproduction in the few pools that were left. This created an enormous infection pressure, prompting the disease to spread rapidly.
Proving a link between climate change and biodiversity loss is difficult because so many overlapping factors may be involved, including habitat destruction, disease introduction and weather variability. This is especially true in the tropics, because written weather records may go back only a few decades, preventing researchers from spotting long-term trends. (Source: website The Earth Institute, Columbia University)
