Quick Take
A fresh look at North America’s coastal wetlands highlights the importance of the ecosystem in our own backyard: Elkhorn Slough. New camera-trap research and ongoing restoration offer rare insight and real optimism for the future of this landscape.
It’s dark in Elkhorn Slough when a raccoon pads through the marsh, plunges its paws into the mud and comes up clutching what researcher Kerstin Wasson calls the marsh’s “salty restaurant offerings”: crabs. Nearby, a bobcat slinks through vibrant pickleweed, its eyes locked on the raccoon, hoping for a chance at its own bite to eat.
These nightly dramas are more than wildlife theater—they’re part of the unseen backbone of coastal wetlands. A new continent-wide study led by the National Estuarine Research Reserve Association (NERRA) using motion-triggered cameras has captured thousands of such moments, revealing that tidal wetlands such as Elkhorn Slough function as crucial corridors and feeding grounds for not just birds but also land-based mammals across North America.
During the summer of 2022, Wasson, research coordinator at the Elkhorn Slough National Estuarine Research Reserve, teamed up with colleagues from 32 coastal sites, setting up at least three motion-activated cameras at each wetland. The cameras were carefully positioned on trees or posts to capture the stealthy steps of the marsh’s elusive residents.
“Wetlands can be hot, buggy and muddy. They can look quiet and empty when you’re out there during the day. But when you put out cameras, you realize that’s not the case,” Kenny Raposa, the study’s lead author and research coordinator at the Narragansett Bay National Estuarine Research Reserve, told Lookout.
What the cameras captured
The synchronized setup allowed scientists to compare wildlife use from coast to coast, producing the first standardized snapshot of how terrestrial mammals move through salt marshes, mangroves and freshwater tidal wetlands. Elkhorn Slough proved a treasure trove of wildlife moments, with footage catching a “slough” of bird species, raccoons, deer, coyotes, bobcats, bears, rabbits and mountain lions. “It definitely uncovers a secret life that most of us never get to see,” said Raposa.
The findings underscore how rare and valuable these habitats are in California. “We have mountains that meet the ocean typically … waves crashing on rocky shores. Having quiet embayments is uncommon,” Wasson said. “More than half of estuarine habitat in California has been lost and so what we’ve got is precious.”
In dry California summers, the contrast is stark: While surrounding grasslands turn brown, pickleweed in the marsh stays green and succulent. Deer and rabbits drift down from uplands to graze, and their predators follow. “We usually think separately about wetlands and uplands,” Wasson said, “that connectivity is really important for them.”
That connectivity is especially visible at Elkhorn. Kevin O’Connor, program director of the Central Coast Wetlands Group at Moss Landing Marine Laboratory, points to the estuary’s scale and geography. “Elkhorn is such a large estuary,” he said. In some stretches, agriculture runs right up to the marsh edge. In others, conservation groups have secured easements and restored former fields, allowing uplands to slope back into tidal habitat. The system also connects strongly to the ocean with sea otters and seals moving in and out through the harbor mouth, creating what he calls definite “opportunities for connectivity to the surrounding environment.”
A coastal “chain of pearls”
Though no Santa Cruz County sites were included in the camera study, its implications ripple north. The region, a mosaic of estuary types feeding into Monterey Bay, features large systems like Elkhorn Slough and Watsonville Slough, as well as smaller estuaries that O’Connor describes as a “chain of pearls.” Waddell Creek, Scott Creek, Natural Bridges State Beach and a number of other wetland areas are modest habitats but together form a crucial corridor for migrating birds and mammals.
Historically, the region’s connections were even broader. O’Connor said that Elkhorn Slough, the Pajaro River and the Salinas River once formed a vast, interconnected estuarine complex. Before levees, harbor construction and large-scale agriculture, the Salinas River drained through Elkhorn Slough to the ocean, while the Pajaro periodically mingled with its waters. Freshwater flowed through wetlands and artesian springs, creating expansive marshes. Today, these rivers drain separately, groundwater pumping has lowered water tables, and much of the historic wetland area has been diked, filled or developed.
Narrowing margins, widening protection
Sea-level rise is tightening the squeeze. Marshes occupy a precarious sweet spot: high enough to avoid drowning, low enough to catch the tides. “As sea levels rise, the window for wildlife to use these wetlands shrinks,” said Raposa.
Solutions are already in motion. At Elkhorn Slough, crews are raising marsh elevations and restoring hydrology in former farmlands. Wasson said she and her colleagues are working to find “win-win solutions” that balance farmers’ needs with wildlife restoration. Another promising step forward is the Santa Cruz County Land Trust’s acquisition and restoration plan of 247 acres at Beach Ranch, which would expand estuarine habitat in Santa Cruz County by 16%.
These efforts, combined with the study itself, offer cause for optimism. Raposa is hopeful about the status of wetlands across the continent and now sees his study as playing a crucial role in that future. “I initially wanted to conduct this study to fill key research gaps,” he said, “but now I realize that our findings, along with the vault of incredible photos we’ve collected, could also be powerful in galvanizing public support for these at-risk coastal habitats.”
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