The Vernal Pools of Mather Field

Photo by David Rosen, Wildside Photography
Photo by David Rosen, Wildside Photography
Photo by David Rosen, Wildside Photography
Photo by David Rosen, Wildside Photography
Photo by David Rosen, Wildside Photography
Photo by David Rosen, Wildside Photography
Photo by David Rosen, Wildside Photography
Photo by David Rosen, Wildside Photography
Photo by David Rosen, Wildside Photography

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The Vernal Pools of Mather Field

Millions of years of geology and evolution have created the spectacular vernal pools at Sacramento County’s Mather Field. These are exceptional examples of a rare wetland ecosystem that is unique to California. Visitors can experience this piece of California’s natural history, just 30 minutes from downtown Sacramento.

What is a Vernal Pool?

A vernal pool is a temporary wetland that fills with water during the rainy season and dries down in the spring. It remains dry for six to eight months awaiting the next winter rains. The plants and animals that are adapted to survive these annual extremes of flood and drought create a changing mosaic of life throughout the three phases of a vernal pool: wet, flowering and dry.

Geology - The role of soil

While the vernal pools at Mather Field range from 50,000 to 200,000 years old, the soils under them began forming more than two million years ago. Dissolved minerals slowly moved down through the soil, eventually forming a hardpan layer. This hardpan lies a few inches to a few feet below the soil surface.

Hydrology - The role of water

In a vernal pool grassland, the movement of rainwater through the soil is stopped by a cement-like layer called hardpan. The water stays perched above the hardpan, where we see it in the shallow depressions called vernal pools. The pools host hundreds of species of tiny aquatic organisms.

Visiting Vernal Pools

For information about visiting the Mather Field Vernal Pools and a schedule of free spring tours check out the vernal pool tours page or call 916-364-2437.

For information about visiting vernal pools in other locations, visit www.vernalpools.org.

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The Three Phases of Vernal Pools

Photo by David Rosen, Wildside Photography

Vernal pools have three distinct phases: the wet phase, the flowering phase, and the dry phase.

Vernal Pool Animals

Although most vernal pool animals are small, their complex food webs sustain many larger species of birds, mammals, amphibians and reptiles. Most of the critters in vernal pools are native to California and many survive only in vernal pools. We know little about them and less than half have been named.

Vernal Pool Plants

Over 200 plant species grow in vernal pools. Half of these are rarely found outside this unique habitat. A single pool typically supports only 15 to 20 species in an unpredictable array of combinations. In that way, vernal pools are a lot like snowflakes – botanically speaking, no two are alike.

Videos: The Microlife of Vernal Pools

Check out these amazing videos of the tiny critters that live in vernal pools, shot by the late, great Bruce Russell of BioMEDIA Associates.

Explore & Investigate

Sacramento Splash - Helping children understand and value their natural world picture

VICTORY - Splash Lives!

Thanks to an outpouring of community support, the Board of the Sacramento Regional County Sanitation District (SRCSD) voted UNANIMOUSLY to continue funding the Splash program.

Click here to find out more.

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Compare your hearing

Owls have one ear that’s higher than the other. This helps them locate the source of a sound in three dimensions: left or right, near or far, and up or down. How could this ability help this Barn Owl?

Have a friend move out of your sight and clap from different places, some high and some low. Your head will turn to find the direction of the sound. We humans have trouble finding the height of a sound. Try tipping your head sideways to see if it helps you.