In winter, vernal pools swarm with aquatic life, most smaller
than a freckle. Frogs and toads come to mate and lay eggs. From
November through March, species race against the clock (and their
predators) to grow up, mate and lay eggs before the pools dry up.
Many vernal pool seeds sprout in November with the first winter
rains. The seedlings remain less than two inches tall throughout
the winter as the pools fill with water, submerging them for
weeks or months.
As the pools dry down in March, the seedlings grow, springing
into bloom during April and early May. Most grow to less than six
inches high. Vernal pool flowers create colorful rings, patches
and ribbons of yellow, white, pink and purple.
The displays change from week to week, as each species gives way
to the next, like a floral kaleidoscope.
During the hot, dry summer months, vernal pools lie brown and
barren among the grasslands. Birds, mammals and insects come to
the pools to feed on the seeds and bulbs of vernal pool plants.
While they are there, other species feed on them.
The sun-baked bottoms of the vernal pools hold the eggs, cysts
and seeds that will give life to the next generation. The winter
rain awakens them, restarting the cycle each year.
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.
