Texas Tech Researcher's Climate Modeling Shows California's Native Plant Species in
Peril from Global Warming
June 25, 2008
Putting land aside now could help these species from going extinct.
Two-thirds of the plants native to the state of California could suffer more than
an 80 percent reduction in geographic range by the end of the century, according to
a recent study.
Climate scientist Katharine Hayhoe, who contributed to the Nobel-Prize-winning United
Nations Intergovernmental Panel on Climate Change, prepared high-resolution projections
for California’s future climate for an ecological study by researchers at the University
of California, Berkeley, and Duke University. Their results will be published June
25 in the journal PLoS ONE.
The study tracked 5,500 native plants of California, including the renowned Coast
Redwood tree, and predicted how changing climate conditions could affect their dispersal
throughout the region. Hayhoe said the climate change likely will push these plants
farther north or to higher elevations, in many cases reducing the range size or even
"The bad news is that the climate change we may experience in the future could have
this kind of drastic impact on California’s native plant species," Hayhoe said. "Many
species may have to move to cooler areas in order to survive. In some of these cases,
for example, when a plant grows near the top of a mountain, there’s nowhere to go.
"But there is some good news. We can use this information to find out where we can
set aside land for conservation purposes now, so these plants can be preserved."
Because endemic species – native species not found outside the state – make up nearly
half of all California's native plants, a changing climate will have a major impact
on the state's unparalleled plant diversity, the researchers warn.
"Our study projects that climate change will profoundly impact the future of the native
flora in California," said David Ackerly, a professor of integrative biology at University
of California, Berkeley. "The magnitude and speed of climate change today is greater
than during past glacial periods, and plants are in danger of getting killed off before
they can adjust their distributions to keep pace."
The researchers caution that their study can't reliably predict the fate of specific
However, the trend is clear: the researchers believe that in response to rising temperatures
and altered rainfall, many plants could move northward and toward the coast, following
the shifts in their preferred climate, while others, primarily in the southern part
of the state and in Baja California, may move up mountains into cool but highly vulnerable
Refugia are places where large numbers of the plants hit the hardest by climate change
are projected to survive.
Coast Redwoods may range farther north, for example, while California oaks could disappear
from central California in favor of cooler weather in the Klamath Mountains along
the California-Oregon border.
Many plants may no longer be able to survive in the northern Sierra Nevada or in the
Los Angeles basin, while plants of northern Baja California will migrate north into
the San Diego Mountains. The Central Valley will become preferred habitat for plants
of the Sonoran Desert.
"Across the flora, there will be winners and losers," said first author Scott Loarie,
a doctoral candidate at Duke University’s Nicholas School for the Environment who
has worked with Ackerly and Hayhoe on the analysis for the past four years. "In nearly
every scenario we explored, biodiversity suffers – especially if the flora can't disperse
fast enough to keep pace with climate change."
The authors identified several "climate-change refugia" scattered around the state.
Many are in the foothills of coastal mountains such as the Santa Lucia Mountains along
California's Central Coast, the Transverse Ranges separating the Central Valley from
Los Angeles and the San Gabriel Mountains east of Los Angeles. Many face pressure
from encroaching development.
"There's a real potential for sheltering a large portion of the flora in these refugia
if they are kept wild and if plants can reach them in time," Loarie said.
The authors argue that it’s not too early to prepare for this eventuality by protecting
corridors through which plants can move to such refugia, and maybe even assisting
plants in reestablishing themselves in new regions.
"Part of me can't believe that California's flora will collapse over a period of 100
years," Ackerly said. "It's hard to comprehend the potential impacts of climate change.
We haven't seen such drastic changes in the last 200 years of human history, since
we have been cataloguing species."
The journal article can be downloaded from the PLoS ONE Web site: http://www.plosone.org/doi/pone.0002502.
Maps of California showing the range change of several species are available at
CONTACT: Katharine Hayhoe, associate professor, Department of Geosciences, Texas Tech
University, (806) 742-0015, (806) 392-1900, or firstname.lastname@example.org;
David Ackerly, professor of integrative biology at University of California, Berkeley,
(510) 643-6341 or email@example.com; Scott Loarie, doctoral candidate at Duke
University’s Nicholas School for the Environment, (707) 217-8479 or firstname.lastname@example.org.