Mountain Messengers

Scientists scale peaks and study plants to understand the impact of warming

(Cheryl Carlin)

(Continued from page 1)

He also points out that the vegetation would not shift in an organized fashion dictated by contour lines; some species move upslope much faster than others. Furthermore, the transition from established species to new invaders could destabilize slopes, he says, leading to enhanced slope erosion and landslides.

For Brad Cardinale, an ecologist at the University of California, Santa Barbara, the loss of any species has potentially dire implications for life on the planet. In a paper published in Proceedings of the National Academy of Science (PNAS) in November, Cardinale and colleagues reviewed 44 studies conducted over two decades that simulated extinction to see how biodiversity affects ecosystem productivity.

Productivity is the term scientists use to describe the fundamental biological process by which plants grow and produce more plants. It may not sound sexy, Cardinale says, but the process is responsible for taking greenhouse gases, like carbon dioxide (CO2), out of the atmosphere, and producing the oxygen, food, wood and biofuels that allow many of the species on the planet, including humans, to exist.

Cardinale, along with many in his field, have long argued that conservation efforts should be focused on the most productive species in an ecosystem, the less productive species could be ignored. He was shocked by a key finding of his analysis: species are not redundant.

In fact, species loss dramatically affects productivity. "As species go extinct from their natural habitat, we could loose 50 percent of the species, and that's probably an underestimate," he says. "I don't think that anyone expected it to be that large. That translates into 50 percent less productivity, 50 percent less oxygen, 50 percent less CO2, 50 percent less food, wood and biofuel."

It isn't so much the loss of a particular species that matters , it is the loss of biodiversity, Cardinale says.

Recent climate change studies have shown that scientists have overestimated the ability of natural habitats to remove CO2 from the atmosphere. Cardinale's analysis points to plant extinctions as a reason "As you cause extinctions, forests, grasslands and such become far worse at taking CO2 out of the atmosphere," he says. "We potentially have this feedback: if climate change causes extinction, extinctions worsen climate change."

For Talbot, scrambling across rounded siltstone hills to establish the first GLORIA site in the North American Arctic, the sense of urgency is often hard to sustain. "A lot of it is boring monitoring work," he says. He'll have to wait three years before he returns to change batteries and download data from the 16 small thermometers he buried at the site.

The big creamy blossoms of mountain avens (Dryas octopetala) and delicate purple blooms of boreal carnations (Dianthus repens) might not be as exciting as many flashier and rarer species, but Talbot understands the value of even these humble plants to the global network. "We're a small part of the whole picture," he says. "One site alone doesn't mean much." But filling in the white spots on the GLORIA map will allow scientists to make sense of changes happening at multiple sites across the globe.

Biodiversity research is still a developing field, Cardinale says. What is clear is that mountain ecosystems may give a preview of what lies in store for the rest of the planet under warming temperatures. "It's scary enough to be seriously concerned about it," he says. "I don't think that we need to preserve every species in order to keep the planet productive. But at the same time, to lose 50 percent of all species, there are some pretty striking implications for humanity that we really haven't struggled with. And we need to begin struggling with them."


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