Carmel Mountain Preserve, a 400-acre mesa top, is truly one of San Diego County’s remaining natural wonders.
When you hike its several miles of trails, you will be treated not only to ocean views, but to a landscape truly unlike any other. On its flat mesa top, there are huge patches of a hard gray moss, called ashy spike moss, that actually have an interesting purpose.
You’ll also come upon puddles of water that settle in the mesa’s depressions, which are actually vernal pools — an amazing environment that hosts species found nowhere else.
The Chaparral Lands Conservancy has called it “a special Noah’s Ark of nature surrounded by suburban development.”
Every type of vegetation found on Carmel Mountain is “unique and imperiled,” it says. Its habitats — Southern maritime chaparral, coastal sage scrub, wet meadows and vernal pools — support more than two dozen rare species, some of which have been listed as federally endangered.
Southern maritime chaparral is a habitat that occurs only on weathered sandstone formations that lie within the coastal fog belt, and exists only in San Diego County from La Jolla to Carlsbad.
“Only about 15 percent of Southern maritime chaparral that historically occurred in San Diego and Orange counties remains, and most of this is located on Carmel Mountain, in Torrey Pines State Park and in Carlsbad and Encinitas,” said Rick Halsey of the California Chaparral Institute.
Characteristic species of this habitat include chamise, white coast ceanothus — a wild lilac that can grow into huge specimens here — and mission manzanita. Endangered species — found only in San Diego and Orange counties — include white-flowering Del Mar manzanita and Orcutt’s spineflower. Threatened species include the yellow-flowering big-leaved crown-beard and shrubby Encinitas baccharis.
The vernal pools, though, are even more precious. Rarely more than 6 inches deep, the pools fill with water only after rainfall and rarely remain filled longer than 45 days at a time. When dry, they simply appear to be lifeless bare spots in chaparral or coastal sage scrub. Half of the plant species growing in California’s remaining vernal pools are found nowhere else on the planet.
“Because of their homely appearance, they provide an excellent example of how the importance of becoming familiar with native habitats and efforts to preserve them can violently collide with the desire to develop property by individuals unfamiliar with their value,” Halsey said.
Indeed, the Carmel Mountain Preserve was dedicated in 1999 after being saved from development by a coalition spearheaded by the Carmel Mountain Conservancy.
Some 97 percent of San Diego’s vernal pools, which once covered some 28,500 acres in the county, have been destroyed, and that naturally includes its rare species. Vernal pools, however, do also exist in northwest Baja.
Both plants and animals of vernal pools must be able to withstand weeks of winter rains and summer drought. Animals that live here include spadefoot toads and their favorite food, the San Diego fairy shrimp.
Living next to the vernal pools is the short-leaved dudleya, a tiny succulent that lives in only five places in the world, all in Del Mar and La Jolla, according to the Chaparral Lands Conservancy. When not in bloom, it looks like the marble-like iron pebbles that are also unique to North County coastal mesas, which helps it avoid being eaten by rabbits and rodents. When it blooms — more rainfall brings more blooms — tiny white and yellow flowers burst open. That ashy spike moss helps them thrive by preventing invasion of weeds and gophers, according to a placard on the trails.