Younger Lagoon: A Rare Resource

I’ve written about wetlands in the past—about how they’re both undervalued and underconserved. I’ve also confessed to being one of those (probably many) people who have to learn about how they work in order to fully appreciate them, since they aren’t always the most aesthetically appealing ecosystems.

As another step in my ongoing personal wetlands awareness project, I recently visited the Younger Lagoon Reserve, a 72-acre parcel of former agricultural land donated to the University of California in 1973. It’s located on the western edge of Santa Cruz, sandwiched between the west side’s housing grid and the brussels sprouts fields that line Highway 1 just outside of town. UC Santa Cruz maintains the property for instruction, research and public outreach.

Map courtesy of UCSC Younger Lagoon Reserve; reserve boundaries in blue

Forty-seven of those 72 acres are open to the public every day. This section of the reserve—the former monocrop farmland—was left to lie fallow between 1973 and 1986. Shortly thereafter, active restoration efforts began to convert the land back to the coastal prairie and seasonal freshwater wetlands that it is now. Along with a trail system and numerous ongoing student-oriented management projects, this portion of the reserve contains UCSC’s Coastal Campus buildings.

The remaining 25 acres holds the reserve’s eponymous lagoon and is only accessible via a docent-guided tour that passes through a locked gate. I signed up for this tour months ago, and I finally had the opportunity to peek behind the barrier last week.

We walked into the property through a literal tunnel of shrubs which comprise the reserve’s coastal scrub ecosystem. Much of this vegetation is coyote brush, lizard tail, and coastal sage (and, yes, poison oak). Most of it was planted about 15 years ago as part of a restoration project, and it continues to serve as a study area for the health of this plant community.

Part of the way through the scrub, an observation deck interrupts the vegetation and allows for viewing of the approximately 100 bird species who live in or use the reserve. Wetlands are critical to many of our avian companions; some live in them full-time, others breed in them, and still others use them as temporary stopover points on their migration paths.

University researchers estimate that Younger Lagoon hosts about 25 resident species, including grebes, scoters, cormorants, mallards, herons, egrets, sanderlings, sandpipers, gulls, owls, swallows, and wrens.

From the observation deck, the path leads down to the beach and its critical feature: the berm. This is the spot where, for most of the year, a sandbar separates the ocean from the lagoon. The lagoon is not fed by a river or a stream; its freshwater is all from rain or local runoff.

However, most winters, the berm is breached at least once by seawater during one of the central coast’s violent storms. Pounding waves blow out the beach, allowing the lagoon’s waters to flow out to the sea while refilling it with ocean water. This past winter, the berm was breached three times.

Photos courtesy of UCSC Younger Lagoon Reserve Virtual Tour

Needless to say, these breaching events result in a fairly radical swing in lagoon conditions. In the summer and fall, when the ocean is calm and the area gets little to no rain and abundant sunshine, evaporation from the lagoon water makes for a high salt/low oxygen environment.

In the winter, a breaching event can turn the lagoon into ocean water. Afterwards, when additional storms bring significant rain to the area, the lagoon’s water can become almost purely freshwater—especially in the upper reaches of the lagoon’s “Y” formation.

These are not easy living conditions for fish, and, not surprisingly, only two species call these waters home: the three-spined stickleback and the tidewater goby.

Photo courtesy of UCSC Younger Lagoon Reserve Virtual Tour

The tidewater goby was once plentiful in California’s coastal estuaries, as it has no natural predators (no one else can survive in the radically shifting oxygen and salinity conditions of these lagoons!). However, the destruction of estuary ecosystems—mostly for beach, housing, and harbor construction—has significantly affected its numbers. Fortunately, in the summer, when UCSC students do goby surveys in Younger Lagoon, they can find one hundred of these two-inch-long fish with just one scoop of a seine net.

Photo courtesy of National Park Service

Breaching events don’t just affect the fish; they radically shift the shape of the beach and the plants and invertebrates that live on them. On our tour, we walked around small patches of beach burr, a type of ragweed that grows on coastal sands where it prevents erosion and enables other species to get established. “Those weren’t here a month ago,” the docent said. “The breach wiped everything out.” But beach burr has deep roots, and it reemerges every year.

It quickly became apparent to me that an experience of Younger Lagoon is a seasonally-dependent one. I was seeing the place two months post-breach, which meant the beach was beginning to reestablish itself. A lot of water made it over the berm, bringing with it the kelp that tints the lagoon water brown.

We’ve had a lot of rain, so that water was fresher than it is at other times of year. And we’re still early for spring blooms, so the native flowers aren’t yet out, and poison oak is still in its stealth stick-only form. I could easily come back in a month or two and see a completely different landscape.

Even the coastal stacks, the huge mudstone and sandstone features that stand just off the beach, change every once in a while. Prior to 1994, the two that can be seen today were joined. Their current separation is a great reminder that all environments are changing and evolving at all times—and that coastal ecosystems are particularly fluid.

In case I needed another reminder of that, I rode home on the West Cliff Bike Path after my tour, swerving by the two sections that have been “reclaimed” by the sea over the course of the past two winters.

Photo courtesy of City of Santa Cruz

We humans are changing the world around us—often in ways we didn’t anticipate and can’t control. And those changes are accelerating.

I’m glad we have portions of some ecosystems set aside to study the effects of our behaviors—and to preserve and even restore some of these unique places.