As California's vernal pools enjoy their springtime flush of activity and color, UC Davis researchers are conducting several new and continuing studies in these unique ecosystems.

Vernal pools are shallow depressions that fill with rainwater. These pools are home to several hundred species of tiny, uncommon plants and animals, all adapted to survive inundation in winter and desiccation in summer.

More than two-thirds of the state's naturally occurring vernal pools have been destroyed by agriculture and urban development. Some animals living in vernal pools are so rare that they are on lists of threatened and endangered species.

"There is great concern that we are running out of time to protect the vernal pools that are left," said Michael Barbour, a UC Davis professor of environmental horticulture. "To do that, we need to know much more about the nature of the plant and animal communities that make vernal pools what they are."

A number of UC Davis faculty members and students have vernal-pool research projects in full swing this season.

- Michael Barbour is principal investigator on a three-year, $445,000 project to thoroughly survey the plants of vernal pools. Barbour has assembled a team of the state's most knowledgeable vernal-pool botanists and three of the world's experts on botanical classification, or phytosociology. The study is funded by the David and Lucile Packard Foundation and the California Department of Transportation.

- Brad Shaffer, a UC Davis professor of evolution and ecology, and his students have three studies underway of tiger salamanders in vernal pools. One project is assessing the genetic consequences of hybridization between native and non-native salamanders in Monterey and San Benito counties. It is funded by the U.S. Environmental Protection Agency for $430,000 over three years.

The second project is assessing the genetic makeup of tiger salamanders across California to help establish conservation plans; this project, in collaboration with San Francisco State University, is funded by a CalFed grant for $850,000 over three years.

The third project is one that Shaffer has worked on without external funding for 10 years at the UC Hastings Reserve; it asks whether tiger salamanders stay in their birth pool, or migrate from one to another.

- Nancy Emery, a UC Davis doctoral student in population biology, is investigating the ecological and evolutionary bases of plant distribution in vernal pools.

"I'm really asking, what causes the characteristic concentric rings of flowers that emerge as a vernal pool's water level drops?" Emery explained. "From the ecological perspective, I'm asking about the importance of the physical stress of being submerged; competition with other plants; and seed dispersal. From the evolutionary perspective, I ask, how can the distribution of a plant population remain constant over long periods of time -- what keeps the plants in the pool?" Emery's advisors are Maureen Stanton, a professor of evolution and ecology, and Kevin Rice, a professor of agronomy and range science.

- Graham Fogg, professor of land, air and water resources (LAWR), is studying the movement of water into and out of vernal pools. Working with him on a two-year Caltrans grant of $150,000 are Randy Dahlgren, also a professor in LAWR, and Thomas Harter, an associate UC Cooperative Extension specialist in LAWR. They are testing two hypotheses: that vernal pools act like kidneys in cleansing surface water of agricultural contaminants and that vernal-pool water ultimately enters streams and rivers and contributes significantly to their summertime volume. Their work will identify and describe the hydrologic conditions needed for sustaining vernal-pool ecosystems.