November 1, 2008
Warming having effect on national treasures
Researchers see rapid decline of species
November 1, 2008
From Walden Pond in Massachusetts to Yellowstone National Park in Wyoming, climate change has already begun to dramatically affect the flora and fauna of these American treasures, according to two studies in Monday's Proceedings of the National Academy of Sciences.
The studies show that the warming of the Earth's atmosphere over the past few decades has caused a loss of many of the flowers that Henry David Thoreau recorded in his book "Walden" and also has contributed to a decline in several species of native animals once common in Yellowstone.
Thoreau first recorded the plants and flowers of the Concord, Mass., area in 1854. Since then, Concord's average annual temperature has risen by about 4.3 degrees, and botanists have kept a consistent record of the region's flora.
Hardest hit are species that don't respond well to temperature increases, including buttercups, dogwoods, lilies, orchids, roses, and violets, says Harvard University biologist Charles Davis, lead author of the article.
Davis says that even though about 55 percent of all natural areas in Concord are undeveloped or remain well-protected, 27 percent of the species documented by Thoreau have been lost, while 36 percent exist in such low numbers that their local extinction may be imminent.
The research points to climate change as the sole culprit and that the loss of species won't be random. "Certain lineages … are far more susceptible to decline under rapid climate change than others," Davis notes.
In Yellowstone, researchers report that climate change and the resulting droughts and lack of snowpack have caused four species of amphibians – including three species of frogs and one of salamander – to go into severe decline.
"Amphibians are a bellwether for environmental degradation, even in natural ecosystems such as Yellowstone … where species have been actively protected longer than anywhere else on Earth," writes lead author Sarah McMenamin of Stanford University.
The findings are based on climate data going back 60 years and remote-sensing data from the past 20 years, she reports.
Climate change is again fingered as the sole cause. "There is no other reason for the regional aquifer to be drying up, at exactly the same time we're seeing this change in climate," she says.
McMenamin adds that "amphibian declines, population crashes and extinctions of entire amphibian species are becoming increasingly common."
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