Life on the Watershed: Lizards, Lyme Ticks and Us

They’ve been hibernating through winter, but the new clear weather is bringing out the sun-loving Western fence lizards--which happen to lower our risk for Lyme Disease. 


From grassland to brush and forest, we spot them basking on rocks, logs, trail-side benches, and other open areas—where they can be easy prey for certain birds and small mammals. But the native reptile has protective devices too, like quick reflexes and the ability to scurry quickly into a crevice or other shelter. It can readily discard its tail to get away--and the tail will grow back.  

   

Spring is mating season, when males establish and defend a territory. The "push-ups" we see them do are indicators of another nearby male, or a female. Females lay eggs, which hatch in mid- to late summer.

Western fence lizards eat spiders and insects. In turn, they are favorite hosts for tick nymphs--and that's a good thing for us.

It turns out that Lyme disease (carried by a tick species called the deer tick) is much lower out here in Western fence lizard country. That's because there's a particular protein in the lizard blood that permanently kills off the Lyme-causing bacterium inside the young insect, So only a small percentage of adult deer ticks are Lyme carriers.

                                                                                                   
                                                                                                                                                                                                                                  

Easter Wildflowers on the Watershed

Areas of serpentine soil are currently yielding a profusion of native wildflowers along the Peninsula Watershed ridges.

Serpentine soil is derived from California’s state rock—the greenish metaphoric serpentine rock originating from the earth’s mantle. Serpentine rock outcrops are closely associated with California fault lines. The soil is high in magnesium and iron, but low in calcium, aluminum, and nutrient-rich clay, so that it is thin and inhospitable to many plant types. Its plant communities are typically composed of stubby, low-growing native grasses and small herbaceous plants.

Conversely, serpentine soil attracts a variety of native wildflowers—many of them rare or endangered—that thrive in the extreme conditions so unfavorable to many of their more common or non-native competitors. To check out this year’s serpentine displays on the Peninsula Watershed, join a guided hike or bike ride along the Fifield-Cahill Ridge Trail.

Life on the Watershed: Nesting Season Under Way

The Peninsula Watershed is home to an abundance of diverse native birds and, after the rainiest winter in decades, spring nesting season is now under way. 

The wet weather has caused some of the hawks and other larger species here on the Peninsula to hold off a little longer than usual this year. But smaller songbirds have begun to nest, and the  tiny iridescent Anna’s hummingbirds are some of the first.   

The roughly 2-inch-diameter hummingbird nest, deep in the  greenery of trees or shrubs, is made of such materials as plant fibers, downy feathers and animal hair bound together with spider silk. Tufts of lichen woven into the exterior help to camouflage it from predators. It’s the female who builds the nest and raises the young alone, without assistance from the male.

For the most part, Anna’s hummingbirds are year-round residents. Their high-frequency wing beat allows them to hover by one flower, gleaning the nectar with a long thin bill—and even longer extendable tongue—before they dart off to the next flower, and the ones after that,  pollinating as they go.  

Spring Forward along Watershed Ridge Trail

Catch vivid springtime green ridges, carpets of wildflowers, ocean vistas and more along the Peninsula Watershed’s Fifield-Cahill Ridge Trail.

Access is by reservation only, with docent-led events scheduled for certain Saturdays, Sundays and Wednesdays. They can range from native plant or birdwatching strolls  to fitness hikes and rides. Among the activities scheduled so far between now and June are two 8-mile round-trip- hikes, a 13-mile one-way hike along the entire trail and a 13-mile but hilly and rigorous bike ride. Events are limited to a maximum of 20 participants; click here to reserve your space. For more specifics on what to expect, visit here.

AND, if you want to tailor a day on the watershed to your particular interest or  pace, consider joining our corps of volunteer trail leaders. Application forms are available here, at the bottom of the page. Or contact our Ridge Trail Program Manager John Fournet, jfournet@sfwater.org, for more information on these and other opportunities.

Sawyer Camp Trail Update: Spring Weeds, Work, and Wildflowers

After all the welcome rain, it’s no surprise that weeds have returned to the watershed, and our crews are back too along the Sawyer Camp Trail. They’re taking out a new groundcover of freshly re-sprouted acacia seedlings, along with different invasive thistle species and poison hemlock. Though a small truck might at times be parked on a shoulder along the trail, community trail use will not be affected.  We'll be planting acorns--with healthy young native oak forests to follow—as soon as the ground is ready for them.  

So, if you go:  late March is a great time to watch for a seasonal highlight—the showy Indian Warrior currently dominating the oak woodland understory along the trail’s southern half.  A cousin to the popular red-orange Indian Paintbrush, this native wildflower seems to have a particular affinity for another oak woodland community regular—the manzanita—and will flourish at the base of the manzanita’s shiny reddish trunk.  It’s said that Indian Warrior was once used by Native Indian Warrior was used by some Native Americans as a muscle relaxer.     

Life on the Watershed: The Inimitable Lichen

Freddy Fungus met Annie Alga, and they took a lichen to one another.    

They made their home in a nearby native oak,

and were always there to support their woodland community neighbors.

There’s nothing else quite like it. Two separate organisms (a fungus and an alga) combine into a totally different life form—lichen. The two original parties coexist in mutual dependence: the fungus is on the outside to capture water and minerals from the atmosphere for the alga within,while the alga produces food for both of them by photosynthesis. Together, they are a ready friend to other oak woodland community dwellers. 

We see different species of lichen  in various colors on rocks, trees and other surfaces—but  only where the air is clean enough for it to survive, like the Peninsula Watershed. Always especially noticeable is the pale greenish lace lichen, drooping in thick long strands from nearby native oaks.

Lace lichen may look like a parasite that’s weakening or killing the tree. But it’s actually a source of extra nourishment because its broad surface area captures nutrient-rich dusts blowing in from the ocean. Rains then wash the accumulated oceanic dust into the ground, where soil bacteria break down the nitrogen for the tree roots to take in. (Trees with lace lichen are healthier and grow faster.) Lichen photos by Shelly Benson  

Along the tree’s branches, lace lichen harbors spiders and insects,which are food for various birds. Some bird species, like house finches, tuck their nests inside lichen clumps, where eggs and checks are protected from predators. 

Others, like hummingbirds, will line their nests with lace lichen, or weave its strands along the outside. Voles and other rodents use it to line their nests, and fallen lichen pieces are food for deer, rabbits and other woodland animals.

For us, the presence of lichen is an indicator of clean, healthy air. Pollution will kill it off.  

Historic Unfailing Dam Ready for Next 130 Years

                                          Lower Crystal Springs Dam after the 1906 Quake

It was built to last. The 1888 Lower Crystal Springs Dam, situated next to the San Andreas Fault,  survived two major earthquakes—the great earthquake of 1906 and the Loma Prieta in 1989—with no damage.  A critical recent upgrade plus our vigilant 24/7 operation ensure that the historic 175-foot-high dam is able to safely contain Crystal Springs Reservoir drinking water even in a year of record rainfall.

The main upgrade under the Water System Improvement Program was the widening of the spillway—an emergency device for the safe release of water during heavy rains—on top of the dam. The new expanse gives us the ability to release 2.5 times more water than before—if necessary. But again, a spillway is an emergency feature---and one that we haven’t had to use for decades, according to SFPUC Local-Regional Water System Manager David Briggs. 

The real safeguard is the day-to-day monitoring, anticipating and adjusting by our system operators.  They open valves to release controlled amounts of water into San Mateo Creek, and divert water northward to San Andreas Reservoir (at left), on to the Harry Tracy Water Treatment Plant (below), and then to customers. They continually forecast the anticipated amount of rain and runoff into the reservoir and assess that inflow’s impacts on reservoir level.  As needed, our operators will  release controlled amounts of water from the dam—but always taking into account the timing of high tides coming up the creek from the bay.   

We’ve been releasing water from the reservoir this way all winter, and have not come close to spilling water over the dam. 

The San Mateo Daily Journal talked with Briggs a couple of weeks ago.  You can read more on what he had to say about the safety of historic Crystal Springs Dam and our regulation of the water system here.