By Greyson Howard, Sierra Sun
Many doomsday predictions of climate change focus on rising oceans, flooding coastlines and submerged cities, but some scientists are watching the Sierra to gauge other significant impacts.
Looking into the future it isn’t hard for researchers to picture the many different Sierra ecosystems — wrapped like bands around different elevations — retreating rapidly upward, squeezing each other and eventually running out of elevation to climb.
As future temperatures rise, predictions are for snow to melt faster and streams to swell earlier, out of sync with the breading cycles of aquatic species like fish and frogs. Dry summers would leave entire forests more susceptible to fire and pests than ever before.
And, many experts agree, the changes become amplified as they move up the food chain, throwing the Sierra Nevada’s entire ecosystem, meticulously established over millennia, out of balance in a matter of decades. The bottom line, some scientists conclude, is the extinction of vulnerable mountain species and increased fire risk for the Sierra’s human inhabitants.
“Our concern is with the rapidity of change — most species can evolve over time and the planet has always been in flux — but it’s the rate of change, which is really unlike anything we’ve been able to study,” said Josh Viers, assistant research ecologist at UC Davis.
The Sierra Nevada has been characterized as the “canary in the coal mine,” according to the U.S. Forest Service, an early alarm for the deleterious effects of rising temperatures. But all parts of the Sierra won’t be treated equal. Despite Truckee-Tahoe’s more northern latitude, the area will likely be hit harder than the taller mountains to the south.
“The area around Tahoe and Donner Summit, for example, would be more affected then Kings Canyon,” Viers said.
And so Tahoe National Forest has been picked as an open-air laboratory for climate change — a focal point in a global issue — with researchers from academic bodies, conservation groups and the U.S. Forest Service gleaning whatever they can learn from the surrounding woods.
“When I started I was a naysayer, ready to poke holes in global warming,” said Carol Kennedy, the watershed project manager for Tahoe National Forest. “I don’t poke holes anymore.”
Retreating trees
Perhaps easiest to predict and already in progress in some cases is the steady retreat of vegetation away from rising low-elevation temperatures and towards ever-shrinking snow melt, said UC Davis’ Viers.
...
The water problem
While rising temperatures will directly affect many species, indirect affects through changing water availability may be even more drastic.
“Between 7,000 and 9,000 feet the rain/snow mix line will be most severely affected,” Josh Viers said.
This means the timing and flow of streams and river could change, possibly three to seven weeks earlier, he said.
“Everything from what’s in the streams — frogs breeding to vegetation along the side of the streams — a whole series of affects, will come from just the timing,” Viers said. The breeding cycles of both the mountain red- and yellow-legged frogs of the Sierra may no longer match with stream flows he said.
Trout require cold water, no more than 20 to 21 degrees Celsius, meaning many streams could become too warm, Viers said. Flowering plants may bloom with high flows before pollinators like bees and mosquitoes emerge.
Aspen trees, already diminishing in the West, are at risk because of drying stream habitat, Nechadom said.
And moisture could be dropping on the order of 40 to 60 percent by the year 2100, Kennedy said.
To view the entire story, please visit website.
