Onward and Upward

I've posted items here previously on the poleward migration of many species (see here and here) -- a predicted consequence of global warming. Another type of migration has been upward; i.e., to higher elevations. This is from an interesting piece in the New York Times about the Grinnell Resurvey Project in California.

The Western harvest mouse, the piñon mouse, the California pocket mouse and the Inyo shrew had never been recorded in the relatively high-elevation park until they showed up in researchers’ traps. On average, since the Grinnell period, these species have expanded their ranges upwards by 2,100 feet in the Yosemite area.

When Dr. Patton saw his first piñon mouse, a cinnamon-colored animal with big ears, on Mount Lyell in Yosemite, he remembers thinking, “What the hell is this thing doing here?” But the mice kept showing up. “They were known up to 7,600-7,800-feet elevation, and I trapped them almost at tree line just below Mount Lyell at 10,500 feet,” he said.

Of course, you can only go so high, and it's no longer so lonely at the top.