SEARS POINT RANCH
Sonoma Baylands & Petaluma River
Restoring the Marsh
In the winter of 2017, as several storms dumped rain on the Bay Area, an unusual occurrence took place along Highway 37 — empty roads. Three weeks of them, in fact. Catastrophic flooding caused this major California highway, used by more than 40,000 cars daily, to close for nearly a month. Climate change on top of human development is likely to make catastrophic occurrences such as this more frequent in future decades.
Parallel to Highway 37 sits San Pablo Bay, the northern extension of San Francisco Bay. It is characterized by tidal and seasonal wetlands, which serve as important habitats for many native species and migratory birds. Additionally, wetlands provide an important buffer between urban areas, agricultural land and infrastructure (such as Highway 37) and the impacts of climate change — including rising sea levels, storm surges and flooding.
In 2005, recognizing the important ecological and economic benefits of wetlands, Sonoma Land Trust seized the opportunity to restore critical marshland along San Pablo Bay by purchasing the 2,327-acre Sears Point Ranch property. Located on the edge of the bay between the mouth of the Petaluma River and Tolay Creek, our vision for Sears Point was to restore tidal, seasonal and riparian wetlands, along with streams and upland habitats, for a wide range of native plants and animals. We were also focused on protecting the open space, and developing recreational and educational opportunities — including extending the San Francisco Bay Trail. While we transferred most of the lowlands ranch (south of Highway 37) to San Pablo Bay National Wildlife Refuge in 2015, we retain the Ralph Benson Center at the Baylands along with the upland portion of the ranch on the northern side of Highway 37.
Our remaining 1,142 acres of the original ranch are characterized by grasslands spanning the vast hillsides and alluvial plains, some of which were also tidal wetlands before the land was diked for farmland in the 1800s. Spectacular wildflower blooms punctuate the hillsides in spring, giving way to golden grasses for much of the rest of the year. Nearly nine miles of seasonal creeks dissect the hills, depositing sediment, nutrients and seeds into the plains. Our goals here are to restore native habitats for a variety of species, including red-legged frogs and burrowing owls, and to provide opportunities for classes, research and guided hikes — we bring people out to walk, enjoy the spring wildflowers, look for raptors and take in the beautiful vistas. And, as a working cattle ranch, we value our relationship with the agricultural community and are assisted in our land management by their cattle, who help reduce the incidence of non-native species.
Fire and Rebirth
The wildfires of October 2017 struck the hills of Sears Point Ranch hard. Two thirds of the grasslands north of Highway 37 burned, including most of Cougar Mountain. The fire also burned the ranch on the southern side of Highway 37, but, fortunately, all of the buildings — including the Ralph Benson Center at the Baylands — were unharmed, along with this burrowing owl who emerged the morning after the fire swept through. Though more than 10 miles of fencing was damaged or destroyed, the low intensity of the fire quickly resulted in abundant regrowth of vegetation and wildflowers.
While momentum for the enormous tidal wetland restoration was ramping up in 2012, there was a smaller, but significant, project underway in the largest drainage of Sears Point Ranch. Three ponds were being constructed next to a meandering seasonal stream. Our intent was to eventually entice the federally threatened California red-legged frog (Rana draytonii) to take up residency and breed there. Success in such work is dependent as much on the understanding of the science as it is on the art of constructing wetlands. For example, the depth of the pond determines when and if it will dry out each year and we needed it dry for at least a few weeks every year. This benefits the red-legged frog and discourages the non-native bullfrog, which preys on the red-legged frogs. Through several years of careful monitoring of groundwater before construction, we determined the right depth. The construction itself mimicked the appearance of naturally occurring wetlands in the local landscape, resulting in three beautiful and functional ponds. The area has been closed to cattle since construction, giving planted willows a chance to mature in pockets along the pond shorelines as well as the creek banks. We have watched small patches of the native perennial grass, creeping wild rye, grow into large fields that provide habitat for nesting mallards. Cinnamon teal dabble in the ponds and Sierran tree frogs breed explosively there each winter. The red-legged frogs have not yet made it, but we hope to see them in the years to come.
Grazing has long been a part of the ranch’s history. When we acquired the property, we worked closely with the rancher lessees and a certified range ecologist to develop a grazing plan in line with our ecological goals and to provide a viable operation for the rancher. Every year, we work to improve the range management and adapt to changing conditions — be they drought, fire or so-called normal conditions. We have an enduring partnership with our lessees, which we greatly appreciate — they’ve ranched in Sonoma and Marin Counties for five generations.
Sears Point Ranch has miles of seasonal creeks that see flashy winter flows and bone-dry summers. Many decades of heavy grazing have resulted in substantial erosion within the creeks, including deep incision, which disconnects the stream from its floodplain. This is important because as the stream cuts deeper and deeper, there is no water to support streamside shrubs and trees, and adjacent seasonal wetlands are thus robbed of moisture. Such is the case in an unnamed creek that drains the diked baylands of the Petaluma River. We call it Lakeville Creek and, in 2021/22, we will complete design plans to restore the creek to its historic elevation. In so doing, we will be restoring habitat for plants and wildlife and returning the water table to near surface elevation. Our approach, known as restoring to Stage 0, is new to the Bay Area, but has been implemented with great success in other regions of the Western United States. Restoring creeks that drain to the baylands, like this one does, is a vital step in restoring complete ecological systems that span the headwaters of creeks all the way to the bay. Complete systems are the most resilient to climate change.
Spring is the time of year when the hillsides of Sears Point Ranch come alive with color. It is also when our members and the general public spend the most time here on guided hikes. The wildflower bloom begins in March, when tens of thousands of violets (Viola pedunculata) blossom across the property. Also known as Johnny jump ups, this violet is the host plant for the endangered Callippe silverspot butterfly. As April approaches, the violets give way to lupine, checkerbloom, owl’s clover, popcorn flower, and more. The blooms are concentrated on the hillsides where the soils are thinner and less nutrient-rich. In the bottom lands where soil and nutrients accumulate, we see fewer flowers and more grasses. The exception is in the fall when the Hayfield tarweed (Hemizonia congesta ssp. lutescens), a late blooming annual that is important for pollinators, blooms profusely on the alluvial plains.