California is a vast, varied state which supports many plant ecology systems; these include landscapes such as deserts, mountains, valleys and beaches. With over 1000 miles of coastline, the beaches of California support a great number of plant species in several ecological systems; amongst these plant communities are California's coastal sand dunes.
The Formation of Sand Dunes
Sand dunes are formed when the wind blows tiny, dry sand particles inland from the ocean shoreline; eventually, drifts of sand are accumulated around plants and other objects. With the continuation of wind patterns, the drifted sand forms a considerable barrier which may still shift until it becomes stabilized by plant growth.
Sand dune fields consists of two or three sets of parallel dunes; the oldest sand dunes are the inland dunes which have become stabilized over time and support plant life. Sometimes inland sand dunes can date back 18,000 years. The outer sand dunes are the dunes which are closest to the beach and have recently appeared.
Plant Life and Sand Dunes
Coastal sand dunes constantly shift in shape due to the impact of ocean waves, storm systems of wind and rain and the interaction of humans and animals: the establishment of plants in sand dunes provides some stability to this fragile environment. However, plants need to be hardy to survive the harsh growing conditions of the sand dunes.
Californian Beach Plants
The new, outer sand dunes support deep-rooted succulent plants. In California, these include plant species such as:
- Yellow sand verbena – (Abronia latifolia) found in beach sand, about 100 to 200 feet from the surf; it is a perennial plant which can tolerate salt spray but not drought or frost.
- Beach strawberry – (Fragaria chiloensis) found on ocean beaches, coastal bluffs and grasslands of Central and Northern California; new roots grow from the red, horizontal stems which help to anchor the plant from winds and shifting sands.
- Silver bur ragweed/Silver beachweed(Ambrosia chamissonis) a perennial plant found on coastal strands and is native to California.
Inland sand dunes are protected from the wind and salt of the ocean; Californian plant species found on inland dunes include the yellow bush lupine (Lupinus arboreus) which is found in sandy places below 100 feet, coastal strands and the Channel Islands of California; it is a perennial plant which flowers from March through August.
The Future of California's Sand Dune Plants
California has 27 sand dune fields; the largest of these are the Monterey Bay dunes. San Diego Bay and Humboldt Bay also have major sand dune fields. Although many of these sand dunes have been in formation for thousands of years, modern day sand dune erosion is threatening the future of the dunes and the life they support.
Major coastal developments along the California coastline have increased both human and animal traffic, together with human constructions of seawalls and dams, which disrupt nature's cycle. The future of California's sand dune plants depends on the measure of the disruption placed on these fragile, ecological environments and the action taken to conserve them.
References:
California Coastal Commission 1987 California Coastal Resource Guide USA: University of California Press
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