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How climate change may be threatening national parks

Thriving forest pests and melting glaciers may make parks a warning system for climate change effects.

By Daniel B. WoodStaff writer, Daniel B. WoodStaff writer / April 9, 2009

Threatened? Warmer temperatures and extended wildfires put Joshua trees in the Joshua Tree National Park in California at risk.

Newscom

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Twentynine Palms, Calif.

With a scruffy, desert floor extending as far as the eye can see in all directions – dotted with the Mojave Desert’s signature spiky, gnarled Joshua trees – veteran park ranger Joe Zarki kneels down in the dust.

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Pointing to an invasive, red brome grass, which has proliferated here in the past few years, he explains why the rise in temperatures that have helped it thrive could signal the end of Joshua trees within a century. “These exotic grasses dry out, which means that the fires we have are getting larger in size, spread more rapidly, and are harder to put out,” Mr. Zarki says.

Unlike lodgepole pines and other conifers that were replenished in Yellowstone National Park after devastating fires in 1988 in Wyoming, the moisture-sensitive Joshua tree grows in a specific microclimate and cannot easily reproduce itself in the wake of widespread destruction. A recent study showed that Joshua trees are not replenishing after fires that now routinely claim thousands of acres. In the 1970s, a typical fire scorched less than an acre.

The disappearance of the Joshua tree may be just one way in which climate change is affecting our national parks. According to researchers, climate change is contributing to:

• The possible loss of all the glaciers in the Glacier National Park within 20 years.

• Dying coral reefs in Biscayne and Virgin Island National Parks due to increased heat and disease.

• Insect pests thriving and destroying forests ranging from the Great Smoky Mountains to Yellowstone.

• Declining water levels at Lake Mead because of extended droughts.

Global climate change is “the single greatest threat to the health of our national parks,” says Michael Cipra, California desert program manager of the National Parks Conservation Association.

In the case of the Joshua Tree National Park, Mr. Cipra points out that the red brome grasses are also fertilized by nitrogen deposited by greenhouse gases moving east from the Los Angeles Basin. The nitrogen levels are 15 to 30 times higher than in undisturbed ecosystems, nurturing exotics such as the red brome and cheatgrass, which now represent up to 60 percent of the park’s biomass from annual plants.

And when the Joshua tree goes, so may the creatures that depend on it – the Yucca night lizard that nests in its decaying bark and the red-tailed hawks and Scott’s orioles that perch in its branches.