The Andes in eastern Peru, with steep slopes and remarkable biodiversity, are what one scientist calls a “perfect laboratory” for studying the effects of climate change. E360 contributor Elizabeth Kolbert trekked there with researchers seeking to determine if tree populations can move uphill fast enough to survive warming temperatures.
“Trees are stunning,” Miles Silman was saying. “They’re beautiful. It’s true they take a little more appreciation. You walk into a forest, and the first thing you notice is, ‘That’s a big tree,’ or ‘That’s a tall tree,’ but when you start to think about their life history, about everything that goes into getting a tree to that spot, it’s really neat. It’s kind of like wine; once you start to understand it, it becomes more intriguing.”
We were standing in eastern Peru, at the edge of the Andes, on top of a 12,000-foot mountain, where, in fact, there were no trees — just scrub and, somewhat incongruously, a dozen or so cows, eyeing us suspiciously. The sun was sinking, and with it the temperature, but the view, in the orange glow of evening, was extraordinary. To the east was the ribbon of the Alto Madre de Dios River, which flows into the Beni, which flows into the Madeira, which eventually meets the Amazon. Spread out before us was Manu National Park, one of the world’s great biodiversity “hot spots.”
We were standing in eastern Peru, at the edge of the Andes, on top of a 12,000-foot mountain, where, in fact, there were no trees — just scrub and, somewhat incongruously, a dozen or so cows, eyeing us suspiciously. The sun was sinking, and with it the temperature, but the view, in the orange glow of evening, was extraordinary. To the east was the ribbon of the Alto Madre de Dios River, which flows into the Beni, which flows into the Madeira, which eventually meets the Amazon. Spread out before us was Manu National Park, one of the world’s great biodiversity “hot spots.”
“In your field of vision is one out of every nine bird species on the planet,” Silman said. “Just in our plots alone, we have over a thousand species of trees.”
Silman, who teaches at Wake Forest University, calls himself a forest ecologist, though he also answers to the title of tropical ecologist, community ecologist, or conservation biologist. He began his career thinking about how forest communities are put together, and whether they tend to remain stable over time. This led him to look at the ways the climate in the tropics had changed in the past, which led him, naturally enough, to look into how it is projected to change in the future. What he learned inspired him to establish the network of tree plots that snakes down the mountain we were standing on.
In the popular imagination, global warming threatens cold-adapted species, like polar bears and Emperor penguins. However, Silman and many other ecologists have come to believe that climate change is likely to have just as great an impact, indeed probably an even greater impact, in the tropics.
Silman, who teaches at Wake Forest University, calls himself a forest ecologist, though he also answers to the title of tropical ecologist, community ecologist, or conservation biologist. He began his career thinking about how forest communities are put together, and whether they tend to remain stable over time. This led him to look at the ways the climate in the tropics had changed in the past, which led him, naturally enough, to look into how it is projected to change in the future. What he learned inspired him to establish the network of tree plots that snakes down the mountain we were standing on.
In the popular imagination, global warming threatens cold-adapted species, like polar bears and Emperor penguins. However, Silman and many other ecologists have come to believe that climate change is likely to have just as great an impact, indeed probably an even greater impact, in the tropics.
The
reasons for this are several. Temperatures in the tropics are a lot less
variable than at higher latitudes, so tropical species tend to have a narrow
range of “thermal tolerance.” Also in the tropics, temperature belts tend to be
wider; thus, to track the temperature changes projected for the nextcentury,
tropical species will have to move a lot farther (and therefore faster) than
temperate species. Meanwhile, because the tropics are already the hottest places
on earth, temperature increases there will create “novel climates” of a sort
that probably haven’t been seen on earth in millions of years. Finally, and
perhaps most significantly, the tropics are where most species actually
live.
“When we think about climate change we often think that high latitudes are going to be the places that are affected the most,” Silman told me. “If you look at the absolute magnitude of change there, it’s high, though it’s surprisingly high in the low latitudes, too. But if we think about what’s important to organisms, it’s places on the planet where climates are going to disappear or climates are going to be so new that they’re going to present challenges to species that they’ve never seen. And if you look at either of those, what you find is that instead of the high latitudes being most affected, it’s the low latitudes, and more than that it’s the highest biodiversity areas of the low latitudes.”
“When we think about climate change we often think that high latitudes are going to be the places that are affected the most,” Silman told me. “If you look at the absolute magnitude of change there, it’s high, though it’s surprisingly high in the low latitudes, too. But if we think about what’s important to organisms, it’s places on the planet where climates are going to disappear or climates are going to be so new that they’re going to present challenges to species that they’ve never seen. And if you look at either of those, what you find is that instead of the high latitudes being most affected, it’s the low latitudes, and more than that it’s the highest biodiversity areas of the low latitudes.”
The next morning, we got up early to watch the sun rise over the ridge. Then we packed up our gear and headed down to the first plot. “Pick out a leaf with an interesting shape,” Silman instructed me once we’d descended into the cloud forest. “You’ll see it for a few hundred meters and then it will be gone. That’s it. That’s the tree’s entire range.”
Silman was carrying a machete, which he used to hack away at the undergrowth. Occasionally he waved it in the air to point out something interesting — a spray of tiny white orchids; a parasitic plant with a bright orange flower; a bright red fuchsia that’s pollinated by a hummingbird whose bill is longer than its body. Several of Silman’s graduate students were also along on the trip. One of them, William Farfan Rios, handed me a leaf the size of a dinner plate. “This is a new species,” he said. Along the transect, the students have found 30 new species of tree, and one entirely new genus. (The new genus has yet to be named.)
“That’s not like finding another kind of oak or another kind of hickory. It's like finding ‘oak’ or ‘hickory,’” Silman observed. “That’s how poorly known these forests are.” continue>>>
Silman was carrying a machete, which he used to hack away at the undergrowth. Occasionally he waved it in the air to point out something interesting — a spray of tiny white orchids; a parasitic plant with a bright orange flower; a bright red fuchsia that’s pollinated by a hummingbird whose bill is longer than its body. Several of Silman’s graduate students were also along on the trip. One of them, William Farfan Rios, handed me a leaf the size of a dinner plate. “This is a new species,” he said. Along the transect, the students have found 30 new species of tree, and one entirely new genus. (The new genus has yet to be named.)
“That’s not like finding another kind of oak or another kind of hickory. It's like finding ‘oak’ or ‘hickory,’” Silman observed. “That’s how poorly known these forests are.” continue>>>
by elizabeth kolbert@Yale: Environment 360
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