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.
