The Vernal Pool is a seasonal body of water with uniquely adapted plants and animals occupying the same pool at different times of the year. Aquatic arthropods such as copepods, fairy shrimps, and diving beetles can be found when the pool is inundated. Iris leaved rushes and vernal barley grows thickly during this period. Once the pool dries, goldfields, tidytips, and calicoflowers can be found within the basin. Vernal pools effectively filter runoff into the water table and provide important habitat for migrating shorebirds and waterfowl. 99 percent of vernal pools have been lost from Los Angeles County alone.