A Seasonal Lake

Mirror Lake was once regarded by park scientists as a stream-fed lake slowly filling in to become a meadow, but as hydrologists developed a more complex understanding of the water's dynamics, they theorized that it is a pool in a seasonal stream. Changes in the volume and speed of the stream's water cause sand to be deposited in and scoured from the pool in cycles. The rockfall that created Mirror Lake altered the streamside habitat of Tenaya Creek, allowing more aquatic and streamside plants to take hold in the pooled water and saturated soils. These plants provide habitat for ducks, frogs, and other aquatic species that prefer still water. The cliffs and rocky crevices above Mirror Lake are also prime nesting spots for peregrine falcons and spotted bats, two of the park's endangered species, while swifts and swallows roost there and feed on insects that thrive in the pooled water, and peregrine falcons prey on those insect-eating birds.

California · United States