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.
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 20 minutes from downtown Sacramento.
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.
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.
Over 200 plant species grow in vernal pools and the surrounding prairie. 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.
Sacramento County intends to establish a vernal pool preserve at Mather Field and manage it for the benefit of the hundreds of resident plant and animal species. Access to some restricted areas of the preserve is made possible through Splash public programs. Public access is mostly limited and prohibited in some of the surrounding areas.
Vernal Pool Public Tours are over for 2018. Thanks to the hundreds of families and individuals who came exploring with us! To be the first to hear about our public tours in 2019, please join our mailing list.
More than 90 percent of California’s vernal pools have been destroyed. We hope you will take time to enjoy and protect those that remain. For the benefit of future visitors and hundreds of vernal pool species, please:
Explore the area only on foot – no bicycles or motorized vehicles.
Avoid walking into or along the edges of vernal pools.
Keep dogs on leashes and out of restricted areas.
Leave all flowers for their pollinators and other visitors.
Unless you are on a guided tour, visit only areas open to the general public.
For 2 billion years, bacteria were the only creatures on Earth. Long before the dinosaurs, a special type of bacteria slowly increased the level of oxygen in the Earth’s air to 20 percent. Without this oxygen other plants and animals could not have evolved, including us.