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Frog Friday: Climate Change

Dried-up breeding site in the Cascade Mountains. Photo by Wendy Palen/Simon Fraser University.

The current and future impact of climate change on biodiversity is poorly understood, but it’s likely to result in large numbers of extinctions and substantial changes in how ecosystems function. Of the 5,743 species of amphibians known to science, nearly 33% (1,856) of all amphibian species are considered threatened with extinction. At least nine species have actually gone extinct since 1980 and another 113 species have not been found in recent years.

Cascades Frogs in amplexus. Photo by Wendy Palen/Simon Fraser University.

Although the cause(s) of these declines and extinctions are variable, climate change has been a contributing factor in many instances. As our climate continues to warm, not all of the changes in our environment are as dramatic as melting glaciers and sea level rise. Many are very subtle and less obvious. Climate change may create problems in the timing of reproduction (known as phenology) for some species. If frogs emerge too early because of warmer winters, they and their eggs may be vulnerable to a late season freeze. For others, a shift in weather patterns may not provide enough water suitable for reproduction and metamorphoses.

An example of the impact climate change can have on frogs can be found in the Pacific Northwest. Far above the raging wildfires, the severe drought affecting most of the western United States is making life very difficult for the Cascades Frog (Rana cascadae). This species inhabits alpine mountain ponds and is able to survive harsh winters buried under tens of feet of snow. But the lack of a winter snowpack and abnormally high summer temperatures has led to massive breeding failures and death to some of the adults. Although frogs have naturally occurring “boom and bust” reproductive cycles, a prolonged drought and continued breeding failures is something the Cascades Frog may not be able to survive. And when you live at the top of the mountain, there really isn’t anywhere else to go. Read more on the plight of the Cascades Frog here.

Photos by Wendy Palen/Simon Fraser University.

  • September 18, 2015