Oregon spotted frog from a 2011 field count. (Fraser Valley Conservancy)

Oregon spotted frog from a 2011 field count. (Fraser Valley Conservancy)

Climate change causing concern for endangered frogs of the Fraser Valley

Declining numbers ‘nerve-wracking when dealing with a critically endangered species,’ says biologist

Climate change with its sizzling heat and damaging drought conditions is doing a real number on critically endangered frogs.

Aleesha Switzer, a biologist with the Fraser Valley Conservancy specializing in frogs, has been closely monitoring climate impacts across the Fraser Valley region.

And the news is not good.

“The past year was really challenging for frogs and salamanders,” Switzer said.

Frogs can be a keystone species, or “the canary in the coal mine” in terms of indicating climate effects.

“I’m worried about what the future holds for them.”

The Oregon Spotted Frog recovery team conducted its annual spring counts of frog egg masses in Chilliwack, Abbotsford, Agassiz, and Harrison Mills.

“The numbers of egg masses laid by these frogs were low this year,” Switzer reports. “While the numbers do fluctuate naturally, even in healthy populations, seeing declines is always nerve-wracking when you are dealing with a critically endangered species.”

Smaller populations, at extreme risk of extirpation, also saw significantly fewer egg masses this year.

The Maria Slough OSF population in Agassiz saw 35 per cent fewer egg mass this year compared to the five-year average.

While the FVC reps can hope this is just a low year for the frogs, that they will bounce back again next year, the outlook is “bleak,” Switzer warned.

The largest known population, referred to as Morris Valley near Harrison Mills, saw 20 per cent fewer egg masses laid this year than the five-year average.

“The number is just on the threshold of being high enough to keep it safe from extirpation, or localized extinction.”

The exact cause is unknown.

“Was the heat dome too intense for sensitive adults and juveniles in shallow wetland habitats? Did flooding events tear frogs away from home ranges, leaving them stranded or unable to find their mates?” she asked.

But results of this year’s breeding surveys serve as a stark reminder that climate change impacts “are very real” and the consequences are dire.

“We need to take action, and we need it now,” Switzer said.

The most significant impact comes from the sustained heat and drought.

Amphibians are wholly dependent on water as many start their lives as tadpoles in ponds. In a drought situation, tadpoles can perish if their pond dries up or overheats. As drought is often accompanied by intense heat, frogs and salamanders on land can overheat and desiccate, resulting in death.

“We need everyone to step up and help however they can.”

Here are some FVC resources from their website, and their programs.

To get involved, check out their Step to It program webpage for climate change information and nature-based solution tips.

RELATED: Finding frogs of the Fraser Valley with Frog Finders

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