California has lost more than half of its coastal sand dunes over the past 165 years, an alarming decline that could have catastrophic effects on the state’s efforts to combat climate change.
A recent study, led by UC Santa Barbara researchers and published in the journal Earth’s Future, is the first comprehensive look at the state’s vital sand dunes. The analysis found that humans are largely to blame for dune habitat loss over the years, as infrastructure replaced entire ecosystems or invasive plants destroyed their ability to thrive. Total dune loss is estimated at around 60% across the state.
“Dunes are not just scenic landscapes; they provide critical habitat for rare and endangered species, and help protect vulnerable communities from erosion, flooding, and storm impacts,” Tim Baxter, the paper’s lead author, told SFGATE via email. “As sea levels continue to rise, protecting the dunes that remain and restoring dunes where possible will become increasingly important.”
Only about 7 square miles’ worth of dunes were lost due to natural causes, the report said.
In coastal metros like Los Angeles and San Francisco, most dunes were erased to make way for growing cities more than a century ago. In those spots, more than 95% of the original dunes have been lost.
Article continues below this ad
Central California has fared better but not by much; the area has lost about 60% of its dunes.
Dunes are a crucial part of the coastal ecosystem and a natural way to combat erosion. They’re also key habitats for plants and animals. Furthermore, since dune fields help supply beaches with sand, their destruction can further exacerbate the problem of the state’s disappearing beaches.
Adding dunes back onto the coast isn’t always a solution to rising seas, but in some places, restoration has shown how successful these efforts can be. At Surfers Point in Ventura, a restoration rebuilt dunes and created a living shoreline, replacing a bike path and parking lot that were at risk of disappearing. The State Coastal Conservancy largely funded the managed retreat project in partnership with the Surfrider Foundation and Ventura County Fairgrounds.
In Santa Monica, another living shoreline project is introducing dunes back into the ecosystem, establishing more than 8 acres between the pier and Venice Beach, with plans to expand that area to more than 30 acres. The dunes have helped retain sand, they absorb wave energy, and they even created nesting sites for the threatened western snowy plover and attracted endangered El Segundo blue butterflies.
Baxter said wide urban beaches like Manhattan Beach (which used to have giant sand dunes that were ultimately shipped to Hawaii) and Ocean Beach would be other great locations for large-scale dune restoration. “These areas could support coastal habitats while also helping to buffer communities from sea-level rise and storm impacts,” he said.
— The California town that just wants to be left alone— America's obsession with California failing— There's one US town where residents live significantly longer. It's in California.— There's a quiet housing fix spreading across California— California remote workers are bringing their high salaries elsewhere— California made them rich on paper and now they’re stuck in place