Vernal Pools

a seasonal habitat

What is a Vernal Pool?

• A temporary spring pond that forms in a depression over a layer of clay soil.

• Only full during the rainy season

• Evaporates during spring and dries up during summer

Special features of Vernal Pools

• Clay bottoms• Seasonal• Specialized

plants and animals

• Rings of wildflowers

• Fresh water

Clay bottoms(with hydric soil)

• Aka “hardpan” or “clay pan”

• Lack of oxygen

• Hard and dry in summer

Inhabited by animals that are adapted to dry seasons

• Tiger salamander

• Fairy shrimp

• Tadpole shrimp

• Birds of prey

• Butterflies

• Solitary bee

Rings of wildflowers

Fairy Shrimp• Only found in

vernal pools• Eggs become

embedded in the hard clay during summer

• Eggs hatch when rains come

• Adults die after egg laying

Tadpole shrimp• Only found in vernal

pools• Endangered• Eggs become

embedded in the hard clay during summer

• Eggs hatch when rains come

• Eggs can remain dormant for many years

• Adults die after egg laying

Solitary Bee

• Solitary Bees emerge in the spring when their host flowers are blooming.

• Female digs a nest in the ground

• Can remain up to four years underground waiting for the rains and flower bloom

California Tiger Salamander

• Endangered• Aquatic larvae

hatch from eggs laid when pools fill in spring

• Juvenile and adults migrate out during dry season