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Tuesday, March 27, 2018

Treehugger Tuesday

From the website Earther:

National Parks Are About to Get a Bunch of Birds They Didn't Ask For
Brian Kahn
Thursday 6:00pm

Acadia National Park is warbler heaven. During the summer, you can hear everything from the rising call of the black-throated blue warbler to the tinkling bell-like call of the black-and-white warbler. Keep your eyes on the underbrush for tell-tale the yellow breast of the Canada warbler, or heavy thickets for the mourning warbler. In all, 25 species of warbler currently occupy park, shaping the ecosystem and soundscape.

But the avian sights and sounds will likely be completely different in just a few decades.

If climate change continues on its current trajectory, 20 of the 25 warblers that currently occupy the park will have no suitable climate. They could be forced to move or perish. Meanwhile, other species could swoop in to take their place.

Acadia is just one datapoint in a massive new study published in PLOS One on Wednesday that looks at how climate change will impact birds across the national park system. Similar stories are likely to play out everywhere from Yosemite’s granite high country to Yellowstone’s bubbling hydrothermal basins, with the study projecting nearly a quarter of bird species will turnover in parks by 2050.

That means that the 300 million annual visitors to parks will, in the future, have a completely different experience. And it means managers will have to make some big decisions on what landscapes they conserve and what species they manage for.

“There’s this recognition of the end of stationarity,” Gregor Schuurman, an ecologist with the National Park Service who worked on the study, told Earther, citing a seminal 2008 ecology paper. “We’re not an intensive management agency, we’re an agency trying to preserve things unimpaired. The end of climate stationarity is a real challenge for us and our thinking.”

Schuurman worked with scientists at the Audubon Society to apply the techniques used in a 2014 paper about climate change’s impact on the 513 species of North American birds to 277 of the 417 sites managed by National Park Service. Data on the historical distribution of these birds came courtesy Audubon’s citizen science bird counts that have taken place for decades. If you’ve participated in those, congratulations, you are now a contributor to a scientific paper.

The researchers fed that data into models that project the climate out to mid-century if emissions continue on their current trajectory, as well as if we made major cuts, and looked at how 17 climate variables—things like mean temperature, daily temperature range, and precipitation in specific months—affected traditional bird ranges across summer and winter.

The result show that between native birds leaving and colonizers showing up, parks will see a 23 percent shift in the types of birds found there if things continue on their current trend (the results are markedly better for birds if we cut emissions). In both winter and summer, new colonizers will outnumber those making an exodus, but the shift is far more pronounced in winter. Joanna Wu, a biologist with the Audubon Society who led the research, told Earther that a number of species that usually migrate to warmer climates in winter may also just stay in certain parks year-round.

Jenny McGuire, an ecologist at Georgia Tech who has done landscape modeling but didn’t work on this study, told the Earther the findings show “that birds will need more food and nesting sites than ever before within the National Parks and points to the critical importance of maintaining or growing park sizes as bird species move into them.”

For hardcore birders—who are part of an estimated $107-billion industry—Schuurman said the study offers a heads up on what species they should be keeping an eye out for.

“I can imagine Big Bend likely seeing new species never before seen in the U.S.,” he said about the park located on the Texas-Mexico border. “Birders may be interested and excited to recording new arrivals.”

But more pressing is what climate change means for park managers. Should Acadia’s superintendent prioritize preserving habitat that lets species living on the southern end of their range hang around a bit longer, or protect habitat that might be more suitable for new arrivals, some of whom may be endangered?

And that doesn’t even get into what climate change will do to the landscapes themselves, the food sources birds rely on and other factors that the current study didn’t weigh into its projections. Even in the absence of perfect information about all those relationships, Schuurman said managers better be thinking about them.

“If we’re talking water birds, do you have aquatic habitat or is there something about climate change that leads you to think we will in the coming decades? You have to have the pieces to put together,” he said.

The choices parks end up making around birds will have huge impacts on other animals as well, since birds with their fancy wings and ability to cover great distances are usually a sign of what’s to come.

“It’s going to challenging to manage for our shifting baseline in the future,” Wu said. “Birds are one of the first responders.”

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