SANTA CRUZ, CA--The remarkable diversity of California's plant life is largely the result of low extinction rates over the past 45 million years, according to a new study published in the journal Evolution. Although many new species have evolved in California, the rate at which plant lineages gave rise to new species has not been notably higher in California than elsewhere, researchers found.
Botanists have long recognized California as a biodiversity hotspot. With more than 5,500 native plant species, 40 percent of which are "endemic" (occurring nowhere else), California has more species and more endemic species than any other U.S. state, and is more species rich than most other places on Earth. The new findings highlight the importance of California as a refuge for plant species that might have gone extinct in other regions during the climatic shifts that occurred in the distant past.
"It seems that California has been an important refuge for plant lineages for a long time," said coauthor Kathleen Kay, assistant professor of ecology and evolutionary biology at the University of California, Santa Cruz. "These findings speak to the importance of protecting areas in California so that it can continue to be a refuge for biodiversity in the future."
First author Lesley Lancaster, now at Lund University in Sweden, became interested in collaborating with Kay after taking a course from her as a graduate student at UC Santa Cruz. She and Kay developed the project together after Lancaster received a postdoctoral fellowship to study plant evolution at the National Center for Ecological Analysis and Synthesis at UC Santa Barbara.
"Because California has so many unique and relatively young plant species, it was long assumed by biogeographers and naturalists that high speciation rates were the cause of California's biodiversity," Lancaster said. "It turns out that these species have not arisen at a particularly high rate in Cal
|Contact: Tim Stephens|
University of California - Santa Cruz