Archive for the ‘Andrea Williams’ Category

by Andrea Williams

This is installment three of a twelve-part series on grasses. Read the previous installment here.

Last month I talked about California’s state grass, purple needlegrass (Stipa pulchra, formerly Nassella pulchra). This month, California’s state rock, serpentinite (although we usually just call it serpentine since it’s made up of serpentine minerals), takes center stage. California was actually the first state to designate an official rock, but serpentine is special and, like our Mediterranean climate, helped give rise to plants found nowhere else in the world.

barbed goat grass

The spikelets of barbed goatgrass look a little like goat heads, although that’s not where the name comes from.

Because of the makeup of serpentine rock, and its slow weathering, serpentine soils are thin, poor, and high in heavy metals. The mineral balance is quite different from what most plants can tolerate, so many plants found on serpentine are endemics: they’re only found on this soil type. Others can grow on serpentine and non-serpentine soils, but may be stunted or appear different when living in the strange soil.

Many weeds take advantage of disturbance and can quickly use resources, outcompeting other plants. But serpentine’s qualities make it naturally resistant to invasion, with a few notable exceptions. That brings us to this month’s grass: barbed goatgrass (Aegilops triuncialis). Originally from serpentine soils in the Mediterranean region and Eastern Europe/Western Asia, barbed goatgrass can thrive in our soils and climate. Not only does it do well on serpentine, the high silica content of the litter it produces is difficult to break down, further altering the soil and making it even harder for other plants to grow! Goatgrass also has a built-in seed stashing strategy: Each spikelet generally has two seeds—one germinates the first year, and the other lays dormant for a year—so even if you get all the plants in a year, the seedbank of this annual has a surprise waiting for you the next.

habitat restoration site

On May 17, help pull invasive barbed goatgrass in this beautiful spot.

Nearly half of our rare plants are found on serpentine soils, which makes these areas so important to protect. You have an opportunity on May 17 to help remove invasive barbed goatgrass from serpentine soils on Mt. Tamalpais, in the Azalea Hill/Pine Mountain area. We’ve been pulling goatgrass from this site for many years, and stemming the tide of invasion. Nine different rare plants call this spot home, and jackrabbits and kites are often seen as well—not to mention our state flower, state bird, and state rock!


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by Andrea Williams

This is installment two of a twelve-part series on grasses. Read the previous installment here.

California state flag

California state flag

You all know the grizzly bear is a main feature of the California flag, but did you ever give a thought to the turf below its paws? While I can’t be certain, I and others like to think they are tussocks of our state grass, purple needlegrass (Stipa pulchra, formerly Nassella pulchra). Did you not know California had a state grass? Purple needlegrass was designated our state grass in 2004, so while it’s only been official for 10 years, this pulchritudinous pastoral plant has been an important and widespread part of our state since well before there was a California. In fact, since individual purple needlegrass clumps can live more than 150 years, there may be plants alive today that have been around since before there was a California!

purple needlegrass

Purple needlegrass (Stipa pulchra) Photo credit: Stephanie Bishop

Purple needlegrass is not only widespread and long-lived, but also quite distinctive in its look. Its inflorescence of delicate purple pennons wave above a mound of fine emerald blades. This fine look has it also available at many native plant nurseries. Some may mistake ripgut brome (Bromus diandrus) for purple needlegrass, but the former—a non-native annual weed—holds a fistful of red bristles on single stalks, with no basal clump of leaves. And while ripgut brome is a danger to grazing animals, purple needlegrass remains an excellent forage species—for cattle, elk, deer, or bears!


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by Andrea Williams

This is installment one of a twelve-part series on grasses.

When someone asks what my favorite grass is, I prevaricate. Who can have just one? If pressed, I’ll pick California oatgrass (Danthonia californica), for reasons I’ll get into another time—but as a genus, fescues (Festuca sp.) are the best. Several of them have made their way into our gardens as lawns and ornamentals, but they’re natural standouts.

Most of our native fescues like to grow in big tussocky stands, sending slender stalks of spikelets to wave above dense clumps of fine leaves. Idaho (or blue) fescue (Festuca idahoensis) is probably our most well-known native; the tight blue bunches accent many a drought-tolerant landscape, and it’s found in our hottest driest spots on Mt. Tam as well. In the wild, it’s a little looser and tends to silver instead of blue, and can be hard to tell from red fescue (F. rubra) on occasion. Red fescue’s leaves aren’t red, but its flowering stalks often are. The fine leaf blades are rolled in long needles, and in most cases are a deep emerald green—the exception being, of course, when it grows in drier spots with Idaho fescue and the two species are almost indistinguishable. Red fescue is at its finest on the coast; the most common cultivar ‘Molate’ is from Point Molate, just on the Richmond side of the Richmond-San Rafael Bridge, where the coastal grassland was nearly lost to development.

California fescue on Azalea Hill

California fescue on Azalea Hill

Our largest and perhaps most striking native fescue (or fesque, as it used to be spelled) is California fescue. Clusters of blue-green leaves grow as tall as three feet and tussocks can reach four feet across; single flowering stalks reach six or more feet in the air. The plant keeps its flowering stalk and stays mostly green year-round, keeping things visually interesting as the seasons turn. I usually find it at moist edges of woodlands and forests, and the stands near Azalea Hill and along Bolinas-Fairfax Road are some of the finest anywhere. Sometimes people have difficulty telling California fescue from the thirsty fungus-harboring invasive non-native tall fescue (F. arundinacea), but the coarse broad green blades and tillering spread of tall fescue are dead giveaways.

So whether you’re seeking a good-looking grass for your yard or on a hike, just remember: it’s fescue to the rescue!

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by Andrea Williams

Photo of temperature-controlled dryers.

1. Senior Collections (Herbarium) Manager Debra Trock shows the temperature-controlled dryers, the first stop for freshly collected plants from Mt. Tamalpais.

The Marin Municipal Water District and the California Academy of Sciences recently wrapped up year two of a three-year citizen science project to catalog the plant life of Mt. Tamalpais. In keeping with new tradition, those who participated in the process were invited to a gathering at the Academy. This year, we were also treated to a tour of the herbarium and the process our plants go through after they are collected and squished flat (see photos 1-5 from the tour).

Seeing our specimens added to the Academy’s herbarium reinforced, to me, the purpose of the project: to use this snapshot in time as a way to compare with past and future plant assemblages. The information we contribute is added to the larger pool (or cabinet, in this case) and can be combined, manipulated or extracted to form knowledge. How is the mountain today different from 100 years ago? When did a particular weed show up? Is this the last stand of the tanoak (Notholithocarpus densiflorus)?

Tanoaks are dying off on the mountain from Sudden Oak Death (SOD), caused by the water mold Phythophthora ramorum. I don’t know that tanoaks will be around in another 100 years, if they will disappear from the wild and live on as botanic garden curiosities and herbarium specimens. A study came out this year looking at the pathogen responsible for potato late blight, Phythophthora infestans, which caused the Irish potato famine. To help us understand plant epidemics, the researchers took DNA from herbarium specimens of infested potato (Solanum tubersoum) leaves from the 1840s and sequenced the pathogen, then compared it to modern strains. Like SOD, the pathogen spread quickly and clonally. But it was soon replaced by a separate strain, which is now the dominant type. Unlike SOD, the potato late blight pathogen and its hosts share a similar root and centers of diversity—plant breeders could use the related dwarf wild potato (Solanum demissum), which evolved with P. infestans in Mexico, to breed in resistance to the blight. While there are other species of Lithocarpus in China, where P. ramorum is from, our tanoaks have diverged into a new genus, and their situation is more like the eastern chestnut and its blight—a native tree decimated by a non-native disease.

However it turns out for tanoaks, a portion of their history is now preserved (likely along with the SOD pathogen) in the California Academy of Sciences, along with the hundreds of other plants from the mountain and the millions of plants in the Academy’s collections; history that will be accessible and shared with researchers for decades or centuries to come.

Photo of walk-in freezer.

2. The walk-in freezer is the next stop, to destroy any pests that may have survived the dryer.

Photo of specimens being flattened.

3. Specimens are further identified, if necessary, glued onto archival paper with an identification label, and stacked with foam cushions topped with a weight to dry overnight.

Photo of Academy's collection area.

4. Plants collected from the mountain are integrated into the approximately two million specimens in the Academy’s collections and into an online herbarium database.

Photo of Miconia specimen.

5. Specimens include not only collections of California’s plant species, but “type” specimens from as far back as the 1700s, such as this Miconia from Brazil, collected during the first voyage of English explorer Captain James Cook.

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Speeding to Recovery

by Andrea Williams

This post is the eighth in a year-long series celebrating the 40th anniversary of the Endangered Species Act. Read the previous post here.

Peregrine falcon

Peregrine falcon (Photo courtesy of Mike Baird)

Fastest animal alive, and thanks to the Endangered Species Act it’s still around. I’m talking, of course, about the American peregrine falcon (Falco peregrinus anatum) and its mind-boggling 200 mph killing dives. In the 1950s and 1960s, peregrine populations themselves were in a dive—from organophosphate (mainly DDT) pesticide use after World War II and also egg collection for falconry. By 1973, when the Endangered Species Act was passed, there were only a few hundred birds in the United States; peregrines were gone from the East Coast and down to fewer than five breeding pairs in California. The ban on DDT in the early 1970s, combined with a strong captive breeding and release program, has helped the U.S. population climb to over 3,000 birds and the American peregrine falcon was de-listed in 1999.

Sometimes my mind tries to make riddles out of how humans have changed the landscape, and how other animals have changed along with that. So instead of asking “How is a raven like a writing desk?”* I ask “How is a skyscraper like a cliff face?” And peregrines have answered the latter question with “I can lay an egg on it.”

During their rebound in the 1980s, peregrine falcons not only returned to their historic breeding sites in rocky spots such as Pinnacles National Monument and steadily increased at Point Reyes National Seashore, but started showing up in cities—nesting on the Golden Gate Bridge and Bay Bridge, as well as on tall buildings and smokestacks nationwide. But it can be dangerous raising young in an urban environment. While there are fewer predators (great horned owls and golden eagles, e.g.) and lots of pigeons, falling out of a nest that’s on a building or a bridge is much more deadly than one on a cliff, and first flights in a city can involve cars and buildings. Reintroduction (augmenting the existing population) stopped in California in 1992 but wild hatchling relocation continued until this year by groups such as the Santa Cruz Predatory Bird Research Group (SCPBRG) for those reasons. Nest productivity for both urban and wildland pairs appears similar in our area.

Generally, if I want to see a peregrine falcon I head to the coast. That’s where I saw my first one in the mid-90s, slicing through the air over the bluffs, and that’s where I most reliably see them today. But starting in February, you can see them anywhere you have an internet connection: numerous nest-cams exist, and the SCPBRG maintains a camera on a nest site at the PG&E building in San Francisco.

*The higher the fewer. Also, inky quills.

Additional resources:

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by Andrea Williams

When I first heard the phrase “fossorial mammals” and how important they were to grassland ecology, I thought of giant ground sloths (Megatherium) and saber-tooth tigers (Smilodon). Sadly, I was wrong. “Fossorial” just means “ground-dwelling,” like “arboreal” means “tree-dwelling.” Although the days of giant sloths and pygmy mammoths have passed, our grasslands are ruled still by fossorial mammals: pocket gophers (Thomomys).

great blue heron eating a gopher

Great blue heron eating a gopher. Herons usually dip the gophers in water (either to drown them or make them go down easier). Photo courtesy of National Park Service/Andrea Williams.

If you have a lawn, you probably know how much earth a gopher moves in a very short time. They’re major engineers in grassland ecosystems, putting up impressive numbers: estimates have 1-3 mounds per day, 70 mounds per month, as much as 2.25 tons of earth moved in a year (or an average of just under 50 tons for a population of 50 gophers). In many grasslands, there are 20-30 gophers in a single acre turning over a quarter of the soil. While this may seem like a nuisance in your yard, it’s enormously important to many wildflowers and plants that need the bare mineral earth to establish; and the burrows are used by dozens of other animals. Plus have you ever seen a coyote, bobcat or great blue heron eating a gopher? Very cool. We generally consider ourselves lucky to still see grassland mammals—the aforementioned coyote and bobcat, plus badgers and meadow mice and ground squirrels—but not the poor unappreciated gopher or mole. Moles, they can smell in stereo, and know which nostril is picking up a particular scent. And although they may make your yard lumpy and eat your favorite plants, gophers (and to a smaller extent, moles) are foundations of a healthy grassland ecosystem, creating space for numerous other plants and animals to live.


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by Andrea Williams

western fence lizard with ticks

Western fence lizard or bluebelly (Scleroporus occidentalis). Note ticks on lizard’s neck.

Every new thing I learn about lizards just reinforces my belief that they are awesome. Growing up in the Bay Area, western fence lizards (Scleroporus occidentalis)—or bluebellies, as they are also known—were everywhere, not just skittering around fences but doing their territorial pushups on rocks or sitting on the stoop catching some sun. I knew then how to catch them with a lasso made from a wild oat stem; that they lost their tails as a defense mechanism; and that the color on their bellies ranged from turquoise to sapphire.

It’s what I have learned in the past few years, though, that really impresses me. Lizards have antibacterial blood. Ticks that feed on lizards (who knew that happens?!) are cleansed of Lyme disease. That’s almost surely why we have so little Lyme disease in California.

One thing lizards cannot do, though, is run on linoleum. We had a lizard stray inside our building at Sky Oaks a little while ago. We tried to shoo it out the front door so it went toward the back, got to the kitchen and all its forward momentum stopped. So I picked it up to take it somewhere it would be safe, checking the blue of its belly and counting the ticks on its neck, silently thanking it for helping to keep me safe too.

The Marin/Sonoma Mosquito & Vector Control District tests Pacific Coast ticks (Dermatocentor occidentalis) for the causal agent of Lyme disease, the bacteria Borrelia burgdorferi, in several areas of both counties. They tested hundreds of nymph and adult ticks and found the rate of “positive” ticks at between 2 and 5 percent. You can see the report and more information here. Their website also has additional information on preventing tick bites and how to properly remove a tick if it bites you.

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Why Do We Need It?

by Andrea Williams

This post is the third in a year-long series celebrating the 40th anniversary of the Endangered Species Act. Read last month’s post here.

In talking about saving rare things, the question of “What good is it?” is often raised. After I set aside my unvoiced, impertinent rejoinder of “What good are you?” I still find the question of a species needing to have use a rather odd one, along the lines of “What good is beauty?” or “Why keep all the pieces of the jigsaw puzzle?” And I could talk about intrinsic value, or about potential undiscovered uses, or about the morality of stewardship over destruction, but I won’t.

I want you to think of a place. A wild place that you love, and what makes it different from any other place for you.

Unlike Mt. Tamalpais, which has thousands of acres of serpentine soils that provide homes for plants found nowhere else on earth, San Francisco only has a few patches. In the early 1900s Alice Eastwood named a new kind of manzanita the Franciscan manzanita (Arctostaphylos franciscana), as it grew on three of the rare patches of thin soil in the City and nowhere else. But San Francisco was a growing metropolis and the first site was lost to a subdivision; two others remained in cemeteries. But when San Francisco’s land became so valuable the buried dead were shipped to Colma, the last populations of Franciscan manzanita were also dug up. Alice Eastwood bemoaned the loss of the wild plant she loved as Laurel Hill Cemetery fell to the blade, even though her colleague took cuttings to grow in a garden; would we celebrate the last wild tigers living in zoos? She grieved the loss of a plant that made “her” place what it was, a place like no other on earth.

In a new chapter for the Franciscan manzanita, ecologist Dan Gluesenkamp doing what many of us do—scanning roadsides for weeds—saw a mound of manzanita growing next to an off-ramp. The area had been cleared of taller vegetation in preparation for the Doyle Drive work near the Golden Gate Bridge. He thought perhaps it was the endangered Raven’s manzanita (Arctostaphylos montana ssp. ravenii), another plant that once grew with the Franciscan manzanita but still exists in a single genetic individual growing as clones around the Presidio. The shrub turned out to be the Franciscan manzanita, now a listed endangered species that has been moved to a different spot on the Presidio.

Mt. Tam Manzanita

Mt. Tamalpais manzanita (Arctostaphylos montana ssp. montana)

So how does this tie to Tam? We have our own “rare” serpentine-loving manzanita, the Mt. Tamalpais manzanita (Arctostaphylos montana ssp. montana), but instead of a few individuals we have several thousand. It’s one of the dominant plants in our serpentine chaparral, one of the plants that make Tam different from any other place. And as the closest living relative to the endangered manzanitas of San Francisco, plant experts turned to our populations to test germination methods for any seeds of the Franciscan manzanita in the soil salvaged along with the plant. Our wealth of serpentine and foresight in setting land aside a century ago may help contribute to the saving of a species, returning a piece of uniqueness back to the world.


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by Andrea Williams

leopard lilies

Leopard lilies on the Mt. Tamalpais Watershed

The Marin Municipal Water District and the California Academy of Sciences held a bioblitz a few weeks ago. I haven’t written about it yet, because all I can give you are numbers and words. I can’t make you present in the Throckmorton Fire Station engine bay in the morning, the air electric with anticipation for the day’s sites, where people would be going, and the things they might see. I can’t take you to a spot lush with green grasses and sedges, show you the impossibly vibrant colors of a leopard lily while you’re immersed in the rank odor of hedge nettle. You won’t be there, part of a focused team, each with a task essential to documenting the plant life at that spot, at that instant of time, blending centuries-old herbarium specimen collection methods with present-day GPS camera technology. You aren’t back at the fire station in the afternoon, surrounded by waves of laughter and chatter as people share details of the day’s experience, pool their data, ask questions about their plant specimens. And I couldn’t save you a piece of MMWD’s birthday cake. But you can share in a solitary facsimile of the process, by taking photographs and locations of plants you see and uploading them to iNaturalist or Calflora, or using one of their smartphone apps, to contribute to the body of knowledge about the mountain.

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by Andrea Williams

This time of year, there’s a lot of perfectly legal tent camping going on around Mt. Tam. Our native tent caterpillars are recreating in the oaks, and it’s fun to see!

Western tent caterpillar

Western tent caterpillar (Malacosoma californicum). Courtesy of Shirley Freitas.

We have three tent caterpillar species in California, probably all of which can be found on the watershed (I just haven’t seen the forest tent caterpillar yet). The most obvious is the western tent caterpillar (Malacosoma californicum), which spins the most complete tents, where the caterpillars hang out, eat, and molt. Their covering of fine orange bristles over a black base gives them a cinnamon hue, but like the other two species they do have some blue and white speckling as well.

While western tent caterpillars are attractive, I must confess to finding the Pacific tent caterpillars (Malacosoma constictum) much cooler—maybe it’s the blue racing stripes down the sides, offset with white tufts, and just a hint of orange in the central black stripe. These caterpillars spin a more rudimentary tent which they just use to change (molt their skin, that is); they feed in communal masses outside the tents.

Forest tent caterpillar

Forest tent caterpillar (Malacosoma disstria Hubner). Courtesy of Thérèse Arcand, Natural Resources Canada, Canadian Forest Service.

The forest tent caterpillar (Malacosoma disstria) doesn’t even make a tent, but spins silken mats on branches or trunks where a bunch of them will group together to rest or molt—the equivalent of just tossing a tarp on the ground to sleep. These dark blue caterpillars have a striking white keyhole pattern down their backs flanked by wavy red-brown lines.

Another noticeable caterpillar on our oaks is the California oakworm, which later in life becomes the California oakmoth (Phrygandia californica). These caterpillars are also mostly black, with creamy stripes and some blue-green and reddish mottling; but unlike the tent caterpillars, the oakworms are hairless with a large, round, orange-brown head. In a good year for them, they can completely defoliate a coast live oak (Quercus agrifolia).

Like most moths, the caterpillars are much showier than the adults. Both young and adults are a couple of inches long, but where the larvae are all blacks, blues, rust and white with patterns and bristles, the adult color ranges from cream to buff to cinnamon-sugar with a couple of paler or darker diagonal lines on the wings. The moths are a nutritious treat for insect-eating birds such as black phoebes (Sayomis nigricans). While the damage from these native caterpillars certainly looks bad, the oaks can easily shake it off and hungry caterpillars have never been known to kill a tree. They just camp out for a few weeks in the spring!

Much of this information is distilled from a fabulous and useful publication from the U.S. Forest Service’s Pacific Southwest Research Station, “A Field Guide to Insects and Diseases of California Oaks” (General Technical Report PSW-GTR-197 July 2006). It is available for free online, although if you can find a printed copy it’s much nicer!

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