Floods Brought Wave Of Frogs And Toads To Missouri, A Boon For Biologists

Sep 18, 2019
Originally published on September 17, 2019 12:33 pm

Frogs and toads need water to breed — and this year, they had a lot of it. 

Months of springtime flooding created near-perfect breeding conditions along the Missouri River, causing a surge in frog and toad populations. For biologists, the population boom has been a rare opportunity to collect information on these animals.

In late spring, thousands of baby frogs and toads emerged from the water and set up camp in backyards in the Missouri River floodplain.

Soon after, Jeff Briggler’s phone started ringing off the hook.

“I was getting phone calls from people, telling me, ‘There’s thousands of frogs in my yard. I’ve never seen anything like this,’” said the Missouri Department of Conservation herpetologist. 

Briggler traveled up and down the Missouri River, visiting backyards to weigh and measure the tiny amphibians. With residents’ help, he collected as many as he could in plastic buckets.

Even rare species, like the Great Plains toad, became common. In his nearly two-decade career, Briggler had only captured a few in Missouri — until this year. 

“Within 15 minutes, I picked up several hundred in a person's yard,” he said. “I may never see that again in my lifetime.”

Why so many frogs and toads?

The masses of frogs and toads are closely tied to unusual weather conditions.

Record-breaking flooding along the Missouri River this spring created additional habitat for the animals, which lay their eggs in temporary pools of water on the floodplain.

Heavy rains on snow-covered land in the upper Missouri River basin triggered flooding in March. Monitoring stations along the river registered record crests that month, some of which topped those set in the Great Flood of 1993.

The rains continued into late spring, breaking records in several states. This May was the wettest May on record in Missouri, Kansas and Nebraska, according to the National Oceanic and Atmospheric Administration.

All that water on the landscape created ideal breeding conditions for frogs and toads, Briggler said.

“I used to read these old accounts in books about the word “raining frogs,’” he said. “What people meant is it was raining so hard, frogs were just everywhere. That's how it felt.”

Appreciation for amphibians

The high number of young produced this year could boost populations of these animals in years to come — which may affect humans and the environment, said Lauren Augustine, curator of herpetology at the St. Louis Zoo.

“These animals are going to control the pest populations, which are probably also booming in these ephemeral wetlands,” Augustine said. “So from a human aspect, amphibians can be very beneficial.”

Because they spend part of their lives in water and later move onto land, frogs and toads also move nutrients across the landscape — a critical part of maintaining ecosystems. 

Augustine, who has studied declining populations of amphibians in Ecuador, said Missourians are fortunate to live in such close proximity to these animals.

“That's something that we take for granted sometimes: how lucky we are to have amphibian species around St. Louis,” Augustine said. “People can generate a better appreciation for amphibians when they see them firsthand.” 

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