What is a Vernal Pool?

Vernal pools are seasonal wetlandsWetland

An area that is fully saturated or flooded with water during at least part of the year. that do not have any permanent outlets, like rivers or streams. Since they have not permanent water source, they only appear during the rainy season and they dry up in the summertime. Vernal pools have an impermeableImpermeable

Something that does not allow water to pass or other fluids to pass through it. Hardpan and claypan are impermeable soils. layer beneath them such as hardpanHardpan

Hard soil that occurs when the soil grains are cemented together by minerals. Hardpan is not good for farming as it does not allow water circulation and is not penetrable by plant roots. or claypanClaypan

Hard soil that occurs when the soil grains are cemented together by fine particles of clay.. This helps them to hold water for several months without it soaking into the ground. The word "vernal" literally means spring and vernal pools are called this way since they result from winter rains and last throughout the spring. Warm weather causes the water in the pools to evaporate and in the summer the vernal pool looks like nothing more than a grassy field.

Because of their unique characteristics, vernal pools are an ideal habitat for the California Tiger Salamander. Fish are one of the greatest natural threats to salamander larvaeLarva (pl. Larvae)

Salamanders remain larvae from hatching until their metamorphosis at around three months., but since vernal pools only last for part of the year, fish do not live in them! In fact, any animal that needs a year-round body of water does not usually take up residence near a vernal pool.

Like the California Tiger Salamander, California's vernal pools are under threat. This is a very bad thing because California is one of the few places in the world with the correct climatic conditions to sustain vernal pools and the kinds of wildlife that depend on them for their survival. The United States Environmental Protection Agency estimates that ninety percent of California's vernal pools have been lost. Just like the California Tiger Salamander, the greatest threat to the vernal pools is mankind. Conversion of wetlands to farmland and urban development have made vernal pools very scarce.

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Here you can find out what a vernal pool is and why vernal pools are vanishing. Also, you will find out what kind of creatures like vernal pools … and what kinds don't.  nextWhat do the vernal pools in the Stanford foothills look like?

Do the vernal pools in the Stanford foothills look like the other ones we see here?