May 16, 2014 Southern California’s Exquisite Coastal Ecosystems
The native ecosystems along the coast and into the mountains of southern California are breathtaking. They have been sculpted by millions of years of climate change and Mother Nature’s biological broom – fire.
The equator is bombarded with the most amount of solar radiation; and warm, moist air constantly rises, cools, rains and by the time the air returns to Earth’s surface its latitudes are about 30 degrees north or south of the equator. This coincides with the world’s great deserts.
Yet, in six unique locales a combination of local factors preclude the occurrence of deserts – instead semi arid shrublands thrive in: southwestern and southern Australia, southern California, central Chile, the Mediterranean Basin and the Cape of South Africa.
Hot, dry summers and mild, wet winters typify southern California’s weather pattern and have been classified as Mediterranean-like climate – an extremely pleasant climate but highly prone to lightning-induced summer fires.
Along the coast in southern California the vegetation is remarkably adapted to living with about 8 inches of precipitation – or desert-like moisture conditions. This plant community is called the Coastal Sage Scrub ecosystem.
The moisture within the fog that bathes this zone is crucial for this ecosystems survival. And not surprisingly plant leaves have ingeniously adapted to trap fog and funnel fog-drip to their roots.
In fact, the rarest pine species in the U.S. – Torrey pine – lives in the coastal sage scrub ecosystem along a sliver of coastline in Del Mar and on a couple Channel Islands. Torrey pines have long, blue-gray flat, wide needles that efficiently trap fog; miraculously their roots are also able to contend with high amounts of sodium in sea spray from the waves crashing along the coastline beneath the mesa where they live.
Torrey pines have also adapted to fire by keeping some of the cones shut tight with viable seeds awaiting the heat of the fire to open them.
In the springtime when this ecosystem is in full bloom with a kaleidoscope of vibrant colours it attracts pollinators like: bees, hummingbirds, moths and butterflies and the air is pungent with floral scents.
Plant odors are thought to help attract pollinators and at the same time repel herbivores from noshing on the leaves. Odors probably evolved alongside the gooey resinous coatings of many plant leaves to prevent water loss.
At least three species of prickly-pear live in this community as well as black, white and purple sages, the bodacious orange bushmonkey flower and Suzie and my favorite the lemonade berry plant. Its fleshy seeds taste like lemon and when mixed with water make a natural lemonade tonic.
Visit the Coastal Sage Scrub in the afternoon and you might just see a monogamous pair of eagles riding the warm land thermals, searching with their binocular eyes for rodents.
Moving from the coastline up the hillside the vegetation and ecosystem receives about 16 inches of precipitation, and these plants are frost-tolerant but not snow-tolerant. This zone is called Lower Chaparral extending from about 980 to 5,250 feet above sea level.
South facing slopes have shrubs with small leaves whereas north- facing slopes have shrubs and trees with larger leaves. Plants are evergreen with resinous or waxy coatings on their hard leaves.
The word “chaparral” comes from “chaparro” – Spanish for the “land of scrub oaks” – as discovered by early Spanish explorers.
Chaparral vegetation has a two layered root system enabling plants some growth in the summer when the Coastal Sage Scrub ecosystem has shut-down from drought.
Lightning induced fire occurs at intervals between 30 and 150 years in the Chaparral. Fascinating adaptations like sprouting from the stump, seed storage in the soil requiring both heat and smoke to germinate, cones only opening after the heat of a fire e.g. knobcone pines, or a combination of these strategies.
Chamise is a common plant in the Lower Chaparral; it responds to fire by stump sprouting and from seed germination post fire. It’s legendary for withstanding heat only bursting into flames when temperatures exceed 800 degrees Fahrenheit!
The black western fence lizard uses its coloration to blend into the landscape post burn, otherwise it would easily be preyed upon by raptors.
The Upper Chaparral zone occurs between 4,265 and 5,250 feet and its home to a number of drought tolerant conifers including the amazing big-cone Douglas-fir that is able to re-sprout new needles after its entire crown has burned – a trait more common in Australian eucalpyts rather than conifers.
Although the last spotted California grizzly was seen in 1908 this species frequented these coastal ecosystems and I’ve found a couple old grizzly trails next to big-cone Douglas-firs. This beauty of beasts used the same trails for generations, placing their paws in the same depressions repeatedly until the trails became a series of potholes.
Despite the fact that 18 million people call southern California home — its coastal ecosystems are magical places to reconnect with Nature and explore her wonders.
Text © by Dr Reese Halter 2013. All rights reserved.