‘More years like 2015 do not bode well for the frogs …’
LINZ — This year’s fierce drought in the Pacific Northwest has given researchers a chance to see how climate change may affect the region long-term, and the outlook is not good for amphibians.
The low winter snowpack and long, hot summer have left some frogs high and dry as their mountain ponds dry up and disappear. Those conditions could be the norm in another 50 years, said Se-Yeun Lee, research scientist at University of Washington’s Climate Impacts Group and one of the lead authors of the study published last week in PLOS ONE.
“This year is an analog for the 2070s in terms of the conditions of the ponds in response to climate,” said Se-Yeun Lee, research scientist at University of Washington’s Climate Impacts Group and one of the lead authors of the study.
“We’ve seen that the lack of winter snowpack and high summer temperatures have resulted in massive breeding failures and the death of some adult frogs,” said co-author Wendy Palen, an associate professor at Canada’s Simon Fraser University who has for many years studied mountain amphibians in the Pacific Northwest. “More years like 2015 do not bode well for the frogs.”
Losing mountain ponds will also affect a much broader range of species. Along with providing breeding habitat for frogs, toads, newts and several other salamanders, the ponds are watering holes and feeding grounds for birds, snakes and mammals that feed on the invertebrates and amphibians that breed in high-altitude ponds.
The assess climate change impacts the researchers categorized wetlands according to their persistence: ephemeral, intermediate, perennial and permanent. Loss of snowpack and increased evaporation will drive changes in all of them.
More than half of the intermediate wetlands are projected to convert to fast-drying ephemeral wetlands by the year 2080. These most vulnerable ponds are the same ones that now provide the best habitat for frogs and salamanders.
At risk are unique species such as the Cascades frog, which is currently being evaluated for listing under the Endangered Species Act. Found only at high elevations in Washington, Oregon and California, Cascades frogs can live for more than 20 years and can survive under tens of feet of snow. During the mating season, just after ponds thaw, the males make chuckling sounds to attract females.
“They are the natural jesters of the alpine, incredibly tough but incredibly funny and charismatic,” said Maureen Ryan, the other lead author, a former UW postdoctoral researcher who is now a senior scientist with Conservation Science Partners.
“It’s hard to truly quantify the effects of losing these ponds because they provide so many services and resources to so many species, including us,” Ryan said. “Many people have predicted that they are especially vulnerable to climate change. Our study shows that these concerns are warranted.”
Land managers can use the study’s maps to prepare for climate change. For example, Ryan and co-authors are working with North Cascades National Park, where park biologists are using the wetland projections to evaluate and update priorities for managing introduced fish and restoring natural alpine lake habitat.