![]() Some anglers aren’t very happy about it, though. Frogs, newts, salamanders, and toads have already started to recolonize lakes recently cleared of fish. In North Cascades National Park, where fish removals have been under way since 2009, the benefits to biotic communities are already apparent, says Regina Rochefort, the research coordinator for the park. Your tax-deductible membership donation of $25 or more entitles… See more › You can read this and other stories about history, nature, culture, art, conservation, travel, science and more in National Parks magazine. “It’s a question of getting the most bang for your buck,” Palen says. To help park biologists determine where best to spend their money and time, Palen and Ryan are developing a model that will prioritize lakes for fish removal by showing which are most likely to persist in future climate scenarios. In larger lakes where gill-netting is unfeasible, pesticides are sometimes used, which brings an entirely different set of challenges. Biologists must visit targeted lakes frequently for five years or more, catching trout with gill nets until all of them are gone. But that is a long and difficult process. To aid amphibian communities, and as part of a larger climate-adaptation strategy, some national parks are considering removing fish from what were naturally fishless lakes. The only places frogs and salamanders are still found in any great number are lakes without trout-a relatively rare commodity-and those many small ponds scattered throughout the landscape that are most at risk for drying out. Once in the lakes, the trout were efficient predators and duly ate almost all the amphibians that lived there. (Although official stocking was discontinued years ago, some dedicated anglers still pack trout into backcountry lakes.) In the 1800s, settlers, and later fish and wildlife managers, stocked many of those ponds and lakes with trout-first for food, and then to promote recreation. But that brings Palen to the second experiment and the force that’s squeezing amphibians from the other side. Palen and Ryan sometimes find little piles of desiccated tadpoles on the cracked muddy bottoms of empty ponds, where the last puddles lingered.įor the frogs and salamanders, the solution would seem fairly straightforward: Simply move downslope to lakes and ponds that are less likely to dry out. When there is less of it, as is predicted with climate warming, the ponds are shallower and thus more likely to dry up. It is a finely tuned system that requires a lot of snow. The tadpoles grow throughout the summer and, after two to three months, metamorphose just before the first snowfall. Females lay their eggs in small seasonal ponds that are fed primarily by snowmelt. ![]() After spending much of the year under several feet of it, Cascades frogs emerge in the late spring and summer to mate. Cascades frogs and other amphibians, like the long-toed salamander, need snow. Throughout the American West, she argues, amphibians have endured-are enduring-two massive unintended experiments. And, for Palen, they are the perfect animals to illustrate what she calls “the amphibian squeeze.” Tough and elusive, Cascades frogs live only in alpine wetlands in the Pacific Northwest and are rarely found below 2,000 feet in elevation. For the past two years, the two of them have waded into ponds in the high alpine regions of three national parks in Washington- North Cascades, Olympic, and Rainier-in search of Cascades frogs. Palen and Ryan are biologists from Simon Fraser University and the University of Washington, respectively. She thinks some individuals may live 25 years or more. She still finds some of the frogs she tagged during her first year in the park. These are small glass capsules about the size of a grain of rice that Palen injects under the frog’s skin. Palen has worked in Olympic National Park since 1999, and in 2000 started tagging Cascades frogs with passive integrated transponders, or PIT tags.
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