Mountain islands signal peril
When I was a kid and my brother and I were trapped inside on
rainy days, we’d occasionally play
”
burning lava.
”
I know
– all lava is burning hot. Once it cools it’s not lava any more.
But cut me some slack. I was 8.
Mountain islands signal peril
When I was a kid and my brother and I were trapped inside on rainy days, we’d occasionally play “burning lava.”
I know – all lava is burning hot. Once it cools it’s not lava any more. But cut me some slack. I was 8.
The rules of the game were simple. We could under no circumstances come in contact with the floor, site of the deadly burning lava. So we’d leap from piece of furniture to piece of furniture, declaring more and more places off limits and devising ever more daring moves until one of us was instantly consumed by the fiery pit.
Game over.
I was reminded of that again last Sunday, when I read “Global warming stalks Yosemite,” a piece by Michelle Nijhuis in the San Francisco Chronicle’s Insight section.
No, volcanoes are not erupting over Tuolumne Meadows, but there’s hard evidence that the place is getting warmer than it ever has in recorded history.
Before the handful of you who like to fight about the reality of global warming begin sharpening your pencils, this is not going to be about the causes or the reality of global warming.
Global warming may be caused by the friction generated by the polyester-wrapped thighs of fat people hurrying across parking lots to the nearest fast food franchise for all I care.
Nijhuis’ article is about observed changes in the landscape, and a peril that had gone unnoticed until now.
A century ago, biologist Joseph Grinnell led a team in a great exploration. The data they collected between 1904 and the late 1930s represents one of science’s towering accomplishments.
They established camps at the crest of the Sierra and collected every living thing they could find. Grinnell himself kept a field journal until a few days before his death in 1939. When he died, it was 3,000 pages long.
Biologists today are retracing Grinnell’s footprints, using many of the same techniques. And they’re finding animals engaged in their own life-and-death game of “burning lava.”
U.C. Berkeley biologist James Patton was part of a small science team that spent the summer near the head of Lyell Canyon, a meadow stretching almost 10 miles among the Sierra’s crown jewels. The John Muir Trail travels the canyon, rising out of it at Donohue Pass.
In 2003, Patton opened one of his traps and found a small mouse with enormous ears. To a person who has spent his adult life studying Sierra wildlife, the verdict was immediate and unfathomable: piñon mouse. The mouse was eventually joined by many others who blundered into Patton’s traps.
Piñon mice are common to the lower elevations of the Sierra Nevada, wherever piñon pine predominate.
Grinnell and company only found them below 7,000 feet, and other researchers confirmed that distribution. Patton’s mice were living at more than 10,200 feet elevation. Given the mouse’s distinctive ears, and relatively high numbers around the Lyell camp, it is impossible to assume Grinnell’s team just overlooked them.
There are other changes. Four other small animals – a chipmunk, two ground squirrels and the pika (think of a large hamster and you’re close) have moved their ranges upslope by an average of 2,000 feet.
For whatever reason, Yosemite is growing warmer. Snow melts earlier in spring. Lyell Glacier is disappearing.
Animals that depend on certain climates and the plants associated with them are being pushed higher and higher, into increasingly isolated islands of habitat.
Worldwide, scientists estimate they have collected solid data on climate effects in 1,500 animal and plant species. Half of them have shifted north or upslope, chasing cooler temperatures.
Why should we care?
Because as they’re pushed further and further into the mountain heights, eventually they won’t be able to go any higher. Then they disappear.
Game over.
