If you've seen a lot of mountains, you probably think of most of them as essentially cone or pyramid shaped, with evenly sloped sides leading up to a relatively pointy summit. (Think: the Matterhorn.) In reality, only about a third of the world's peaks fit that mold, according to a new study. That fact might seem trivial, but it actually could re-shape conservation priorities for mountain wildlife in a warming world.
"Species are responding to climate change in a multitude of ways, including by shifting their ranges in latitude and elevation," in search of the colder temperatures they're used to, Princeton University graduate student Paul Elsen and University of Connecticut conservation biologist Morgan Tingley write in Nature Climate Change.
As mountain-dwelling species move farther up, the conventional thinking goes, they'll have less room to move around and less to eat, which could lead to extinction. Imagine a few thousand black bears roaming around the base of Mount Shasta, and then imagine trying to cram all of them onto the California peak's summit. They wouldn't last long, even if there weren't all that snow and ice.
Only about 32 percent of the world's mountains resemble the cone or pyramid-like Alps, where the amount of room to move around shrinks as you climb higher.
The trouble is, no one had actually done a detailed study on the shape of our global landscape, so a key assumption in the argument—that there's less room at the top—could well be wrong. To find out, Elsen and Tingley gathered data on 182 mountain ranges, which they then fed into software designed to compute how much surface land area exists at each elevation in a given mountain range.
To their surprise, Elsen and Tingley found that only about 32 percent of the world's mountains resemble the cone or pyramid-like Alps, where the amount of room to move around shrinks as you climb higher. The largest category, which covers 39 percent of the planet's mountain ranges, includes peaks like Washington's Mount Shuksan, where steep sides lead to a broad plateau beneath a smaller summit pyramid. Another 23 percent resemble the mesas of the American southwest—relatively gentle slopes that give way to steep cliffs below a wide, flat top. The remaining six percent rise steeply from as low as sea level to relatively open, flat tops.
These findings paint a more nuanced picture of climate change's impact on mountain life. While true mountaintop species like snow leopards might indeed face "the threat of species literally being pushed off mountaintops," others may find opportunities in open areas at higher elevations. And while, as Elsen and Tingley point out, there are other "pinch points" to worry about—including the steep Himalayan walls that divide low- and high-altitude habitats—policymakers should take the world's mixed topography into account when setting conservation targets.
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