Numbers of red-legged frogs and other amphibians throughout the Puget Sound region continue to decline, and scientists have found a misfit between development regulations and the actual lives of migratory amphibians.
They’re burrowed under snow and leaf litter, and tucked deep beneath the bases of sword ferns, waiting out deep winter after migrating as long as three miles to get to their home forests — a nearly heroic journey, when it’s traveled one hop at time.
Red-legged frogs and other amphibians throughout Puget Sound country will be on the move once more. The red-leggeds in particular are headed for breeding ponds usually at least a half-mile away, sometimes far longer — even clocking three miles, scientists have found.
That some frogs travel so far is a surprise to scientists who have studied their migrations to better understand why populations of some native species, such as red-legged frogs, continue to decline in suburban areas of the Puget Sound region.
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What they found was a misfit between development regulations and the actual lives of amphibians. The animals’ movements through the seasons of the year don’t fit into tidy buffer zones, drawn in tight circles around breeding ponds. The wetlands they use for breeding and rearing are protected, but the success of those regulations is problematic. And too often, roads slice right through the migratory corridors amphibians use, and development devours the forests they need to live in much of the year.
Ironically, protections against filling and destroying wetlands even drive some developers to clear and build on the nearby upland forests that amphibians need, rather than go to the trouble and expense of avoiding or offsetting wetland destruction.
King County has adopted some of the most generous habitat protections anywhere, which in combination restrict clearing of forests, protect wetlands, and require connections between wetlands and associated forests to protect migration routes. But even the largest buffer zones, reaching 300 feet from sensitive areas in some circumstances in King County, are not always enough for amphibians on the move.
And in developments built under old rules, and in jurisdictions with less stringent regulations, amphibians often face total barriers to movement — just one more challenge for animals already battling disease and competition from exotic predators, such as bullfrogs.
The result is that common backyard animals every Puget Sound kid grew up with, such as Western toads, red-legged frogs and northwestern salamanders, are disappearing or in decline, some population surveys show.
In seven of 18 King County wetlands surveyed between 1993 and 1997, Klaus O. Richter, a senior ecologist for King County, found native species declined and some even disappeared.
“It’s not just the wetland alone that is really important,” Richter said. “They only use the wetlands for two weeks to a month, a very limited time, when they go to the wetlands to breed. But then they go to the forest to live their lives, and what we have found is that the forests are disappearing, and getting smaller, and the access to them is declining because of our sprawl.”
He remembers going to Beaver Lake Park in the Sammamish Plateau in early summer and finding the grassy areas near the lake alive with toads. “The ground would be moving, just crawling with baby toads,” Richter said.
The toads used to migrate between the lake and forest nearby. But today the forest is home to Beaver Lake Estates, and roads, including busy 228th Avenue, slice through the toads’ former migratory routes.
“I’ve been going back and looking, and I haven’t seen a toad,” Richter said. He sees a diminishing, not only of the food chain and biological diversity of the area, but of the human pleasure in living in a place so alive. “It’s sad,” he said, “they are just gone. People don’t even know what used to be here. It’s the extinction of experience.”
Counting road kills
It’s the early morning that is the most telling, says Joanne Schuett-Hames, a biologist with the Washington State Department of Fish and Wildlife. Schuett-Hames is studying a four-mile section of largely rural road west of Olympia, to assess the toll taken on amphibians by cars. After a warm, wet night in spring or fall, she’ll head out to see what happened in the night, early enough to get there before the crows and other scavengers.
She is counting road kills of seven species, including northwestern salamander and red-legged frogs, and what she has learned surprised her. The red-legged frogs are traveling routinely as far as one-half to one mile as they disperse from their breeding pond and head for their upland forest. Many don’t make it. Schuett-Hames has found as many as 100 amphibians dead on the road, killed in just one night, when she tallies her survey, red-leggeds among them, along with other species of frogs, salamanders and newts.
“We need a different way to think about how to have these animals have safe movement to get to these places,” Schuett-Hames said. “Red-leggeds are one of the most interesting: They are doing these really long travels.”
Some of her photos capture frogs, newts and salamanders as they are crossing the road, skins gleaming with rain, legs flying, and tiny toes gripping pavement that seems a vast expanse for their tiny, delicately made bodies.
They are en route to and from a large wetland complex that fuels amphibian populations for large distances around it — bigger than anything local regulations will protect.
Taking frogs into account
John Kaufman is developing several home sites on 40 acres off the road Schuett-Hames has been studying, and he has talked with her on several occasions about the frogs. “I am trying to be open and listen to what they have to say,” Kaufman said.
It’s not easy: “I’ve been strung out forever waiting for permits,” Kaufman said. “When somebody wants to come talk about frogs and things, it’s about the last thing you want to hear.”
Kaufman is working with scientists to develop more information about the frogs and their movements, and how roads affect their migration and survival.
“He’s been very supportive,” Schuett-Hames said. A range of options, from culverts to signs or speed bumps, urging drivers to slow down, are under discussion, she said. “The primary objective is to help the animals survive better over time, as more development and traffic occur.”
Lynda V. Mapes: 206-464-2736 or firstname.lastname@example.org