Yosemite

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Alpine Chipmunks’ Habitat and Gene Pool are Shrinking

One of the few mammals unique to California is also one of the most threatened by climate change.

Risa Sargent

The alpine chipmunk only lives in California, and its habitat is shrinking.

The alpine chipmunk, found in Yosemite’s high country, has moved upslope as temperatures have warmed over the last century.

Now a new study out yesterday from the journal Nature Climate Change shows a warming climate may also be affecting the species’ genetic diversity. Listen to my radio story about the study on today’s California Report.

The alpine chipmunk is one of the smallest chipmunks in California. It’s also got a uniquely striped face. It’s hard to see these chipmunks in the wild unless you strap on a backpack and climb some 10,000 feet high in the Sierra.

That’s what study author Emily Rubidge did as a PhD student at UC Berkeley’s Museum of Vertebrate Geology. She’s part of a team that’s been ambitiously updating Joseph Grinnell’s historic survey of Yosemite’s wildlife from the early 1900s.

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Yosemite’s Fiery Future

Tim Walton

Photo: Tim Walton

California’s Yosemite National Park has been scarred by several big fires in recent years—the latest contained less than two months ago. But new research affirms that this crown jewel among national parks is likely to have even more fire in its future.

In late August, when fire crews attacked the Big Meadow Fire in Yosemite, it was hard to blame nature for the 74-hundred acres lost. That was a “prescribed burn” that got out of hand (or “escaped,” as the official report puts it). But nine out of ten wildland fires in the Sierra start with a lightning strike. Newly published work suggests that as California’s climate changes, the combination of warmer temperatures, less snow and more lightning strikes could mean 20% more fires by mid-century.

USGS research forester emeritus Jan van Wagtendonk co-authored the study with James Lutz at the University of Washington. He says they studied 20 years of Yosemite fire data to identify a trend. The mechanism starts with the oft-cited warming scenario, causing more rain and less snow at upper elevations.

“What happens in the mountains is that, as snow recedes in the spring the moisture in the fuels follows,” says van Wagtendonk. “The fuel starts drying out earlier and we extend the fire season by having more days available for fires to burn.”

But there’s another wildcard in the deck: lightning. Separate studies suggest that higher concentrations of atmospheric carbon dioxide will set the stage for more lightning strikes.

The study assumes a 17% reduction in snowpack by 2050—under the relatively modest B1 warming scenario, drawn from IPCC models. The results are in line with other climate studies that imply not just more fires, but more intense fires as the climate warms. It’s a trend, says van Wagtendonk, that has already started:

“We were able to trace, through satellite imagery, the change that we’ve seen in the severity of those fires just over the past 20 years, so it’s been obvious to us from those data that whatever temperature trends are occurring today are already having an effect on increased severity.”

“We see more of the same,” said the forester, “and a continued increase in both size, number and severity of fires.”

Yosemite fires from 1984-2005. The black triangles are fires sparked by lightning. Image: International Journal of Wildland Fire.

Yosemite fires from 1984-2005. The black triangles indicate fires sparked by lightning. Image: International Journal of Wildland Fire.

Scott Stephens, an associate professor of fire science at UC Berkeley, says lightning is changing the landscape in more ways than one.

Stephens recently told KQED’s Central Valley Bureau Chief, Sasha Khokha: “In Yosemite and Sequoia-Kings Canyon, they manage quite a few lighting fires in the wilderness area, away from people, and they allow these things to burn for months and months and months to try to allow that lighting fire to begin to shape the landscape again like it did 100 or 200 yrs ago. Those types of events probably increased the resiliency of the forest to deal with climate change and other impacts.”

The article is published in the current issue (10/27) of the International Journal of Wildland Fire.

KQED’s Central Valley Bureau Chief, Sasha Khokha, contributed to this post, as well as to the radio report.

Paddling to the Sea

Jessie Raeder is Bay Area Organizer for the Tuolumne River Trust. More than 200 paddlers are expected to take to the river between now and June 7, for this river awareness relay. Raeder offers this dispatch from the starting line, near the headwaters in Yosemite National Park.

By Jessie Raeder

Paddle to the Sea got off to a roaring start over the weekend.  Melting snow caused by an early heat wave in the Sierras had the river pumping at much higher flows than rafters typically face. The Tuolumne is usually rated Class 4–but goes to Class 5 when flows get over 4000 cubic feet per second.   This weekend saw the river flowing at 7000 cfs! For a while it looked like we might have to cancel all the whitewater trips due to safety concerns, but in the end one trip did go on and needless to say it was an epic journey for our Paddle-to-the-Sea team.

A paddler takes on the Clavey. Photo:

A paddler takes on the Clavey. Photo: Patrick Koepele, Tuolumne River Trust

Meanwhile, an international team of 12 hotshot kayakers ran the Clavey River, a tributary of the Tuolumne and one of only three remaining free-flowing rivers in the Sierra.  The Clavey is a class 5+ river that’s rarely run and only by experts.

Paddle to the Sea is a three-week festival to foster stewardship of the Tuolumne River. Hundreds are joining in this epic journey from the Sierra to the Sea. Kayakers and rafters will begin on the upper stretches of the Clavey and Tuolumne Rivers, travel through the Central Valley where canoers take the lead, pass through the confluence of the Tuolumne and San Joaquin Rivers, and sea kayakers will finish the trip in San Francisco Bay.

A changing and increasingly unpredictable water supply will be the first way that most people in California experience climate change affecting their own lives.  Here in the Bay Area, tap water for 2.5 million people comes from the Tuolumne River, whose headwaters start with melting snow from the Lyell Glacier (picture attached).  That glacier is on the retreat, and more frequent droughts are expected throughout the Sierra.

Paddle to the Sea is meant to demonstrate that issues that affect one section of the river ripple up and down the watershed.   Bay Area water users share this resource with farmers in Modesto, anglers in Yosemite, the commercial salmon industry on the Pacific, and a host of native fish, plant, and wildlife species, many of which are endangered.

As population and demand for water continues to grow, California will be faced with many questions about how we use water, and where it will come from.  The Tuolumne River Trust is working to ensure that we turn to water efficiency and water recycling as much as possible–alternatives which are far more sustainable and renewable than continuing to take additional water from the Tuolumne River, which has been the solution most turned to in the past.

 

A Long Trek to a Shrinking Glacier

img_5833-300.jpgThe glaciers in the Sierra Nevada are melting fast, and I really wanted to see one before it was too late. Earlier this fall, I got my wish. Reporter Sasha Khokha and I were lucky enough to travel to Yosemite and tag along with geographer Hassan Basagic on his trek to photograph the Dana Glacier as part of his research documenting the retreat of the Sierra glaciers.

The hike to Dana Glacier was stunning. We parked the car just outside Yosemite’s Tioga Pass Gate, which is at close to 10,000 feet in elevation, and began bushwhacking almost immediately. We climbed to the base of the glacier traveling through soft green meadows, up and over mountains of multi-colored boulders, and along the edges of electric blue and green alpine lakes. Not one cloud passed over our heads all day long.

While the climb was memorable for its beauty, what made the day truly outstanding was having a guide explaining the landscape around us each step of the way. Since 2003, Basagic has been tracking the changes in the glaciers of the Sierra using historic photographs. His research contains comparison photographs of several other Sierra glaciers, including the Lyell and Maclure glaciers.

Californians are thinking more than ever about water, snow pack, and our glaciers due in part to a couple of dry years and two pretty severe fire seasons. In October, Tom Knudson of the Sacramento Bee wrote an interesting piece about his trek to the Lyell Glacier with a team of scientists. Knudson and team found that like Dana, the Lyell Glacier has shrunk dramatically since 1883.

While the hike to Dana was spectacular, the glacier itself appeared less than majestic. It looked vulnerable, clinging to the side of a massive bowl, a remnant of the sea of ice that once filled the entire valley. It looked so small and fragile that I was not surprised when Yosemite geologist Greg Stock told us in an interview the next day that it’s likely the Dana Glacier will be gone in the next 25-50 years.

Check out the videos and audio slidehow of our journey to the Dana Glacier.

Listen to the radio report.

Small Mammals on the Move in a Warming Yosemite

Over the last century, small mammals in Yosemite National Park have been on the move.  A recent study published in today’s issue of Science finds that as temperatures have warmed (a 3-degree Celcius increase in the park’s night-time low temperature) and Sierra glaciers have continued to melt, small mammals like mice, shrews, and chipmunks have moved to higher elevations or reduced their ranges in response to the climate.As part of the Grinnell Resurvey Project, a team from UC Berkeley’s Museum of Vertebrate Zoology headed up by professor Craig Moritz recently documented these changes in Yosemite by conducting a survey of the animal populations and comparing their data with an extensive data set collected in the same locations by field biologist Joseph Grinnell in the early 20th century.Of the 28 small mammals observed in the study, half had expanded their range upslope by more than 1,600 feet.

Since the higher up you are, the cooler the temperatures tend to be, recent research suggests that the mammals already living at high elevations may eventually face “mountaintop extinctions,” as they run out of room to climb higher if temperatures continue to rise. For example, the alpine chipmunk, which in 1918 was common at 7,800 feet, was recently nowhere to be found below 9,600 feet, according to the study.

Scientists acknowledge that changes in populations and animal communities are natural, but, Moritz says, what is less common is the speed with which these changes occured.