Jun 25, 2008 5:36 pm US/Pacific
Study: Global Warming Will Devastate Calif. Plants
BERKELEY (AP) ―
As much as two-thirds of California's native plants could lose most of their current habitat if temperatures increase sharply over the next century as some climate scientists predict, according to a new study.
The report by researchers at the University of California, Berkeley, Duke University and other institutions projects how global warming could affect the roughly 2,400 plant species only found in California, including live oak, blue oak, scrub oak, California bay laurel and whiteleaf manzanita.
Up to 66 percent of the plants would disappear from 80 percent or more of their present ranges if greenhouse gas emissions continue to grow at their current rate, according to the study published Wednesday in the Public Library of Science's online journal, PLoS One.
But there would be much less impact on the state's biodiversity if emissions drop to below 1990 levels by the end of the 21st century, the researchers found.
While plants can respond to changing climate over thousands of years, 100 years isn't enough time for most species to adapt to the dramatic environmental changes predicted by climate models, said David Ackerly, a UC Berkeley biology professor and a study co-author.
"Our study projects that climate change will profoundly impact the future of the native flora in California," Ackerly said. "Plants are in danger of getting killed off before they can adjust their distributions to keep pace."
The researchers project that many species will shift north and toward the coast in response to rising temperatures and changing rainfall patterns, while others may move up into the mountains. Regions such as the northern Sierra Nevada or the Los Angeles basin could lose much of their native flora.
The study identified areas where large numbers of plants affected by climate change could relocate and thrive, including the Santa Lucia Mountains along the Central Coast, the Transverse Ranges separating the Central Valley from Los Angeles and the San Gabriel Mountains east of Los Angeles.
The researchers say protecting these regions, which they call "climate-change refugia," will be crucial to maintaining the state's biodiversity.
"Across the flora, there will be winners and losers," said Scott Loarie, a study co-author and Duke University researcher. "In nearly every scenario we explored, biodiversity suffers -- especially if the flora can't disperse fast enough to keep pace with climate change."
Surface temperatures rose almost 1 1/2 degrees Fahrenheit in the past century, but much of that was in the past 50 years, according to NASA. Eleven of the past 12 years are the warmest since accurate record-keeping began in 1850.
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