Archive for the ‘Andrea Williams’ Category

by Andrea Williams, Vegetation Ecologist

This is installment seven of a 12-part series on grasses. Read the previous installment here.

Serpentine reedgrass (Calamagrostis ophitidis) is rare. We have tons of it.

Such seemingly incongruous statements happen quite a bit on Mt. Tam, through the magic of the “Matrix of Rarity.” It depends on the scale at which you look. The California Native Plant Society (CNPS), which reviews the distribution of and threats to California’s flora, keeps an inventory of plants and the degree of rarity they display. So statewide (and worldwide), there may be fewer than 100,000 individuals, but if all those individuals are in a three-square-mile area they may seem abundant in that spot.

  Abundant where found Few plants per population
Broadly distributed Common species, e.g. purple needlegrass (Stipa pulchra) Often rare, e.g. semaphore grass (Pleuropogon)—next month’s topic!
Narrowly distributed Often rare, e.g. serpentine reedgrass Nearly always rare

Almost half of our rare plants are restricted to serpentine soils; like wetlands and beaches, these habitat types are finite. Often, rare plants in these spots will be quite common and you may wonder why they’re considered rare at all. Mt. Tam manzanita is actually so common it’s the dominant plant over most of our serpentine soils. Serpentine reedgrass is pickier still, preferring to grow at the edge and in the interstices of serpentine chaparral.

Serpentine reedgrass

Serpentine reedgrass (Calamagrostis ophitidis)

Unlike Mt. Tam manzanita, though, serpentine reedgrass can be found outside Marin in Sonoma, Mendocino, Napa, and Lake counties, although we do have the bulk of it. This handsome perennial grass raises fluffy, open spikes one to three feet above clumps of deep green upright leaves. Some of the finest serpentine reedgrass grassland—a rare vegetation type—can be found along Pine Mountain Road opposite Azalea Hill.

Another factor feeding into a plant’s status is the threat to its populations. Serpentine reedgrass populations on Mt. Tamlapais are pretty stable: No one is bulldozing populations to build things, they don’t need fire to germinate, their habitat isn’t being taken over, no diseases are wiping them out. But in other counties that may not be the case. Like with the drought, we need to consider ourselves lucky that we are where we are and have what we have (90% of average water storage and 40 rare plant species), and continue to conserve.

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by Andrea Williams

This is installment six of a 12-part series on grasses. Read the previous installment here.

Even though I’m a cat person, every February I love to watch the two-day spectacle of the Westminster Kennel Club Dog Show. I’m just a taxonomist at heart, and I enjoy spotting the subtle differences between the American foxhound, Harrier, and English foxhound; or how the different groups came to be and why the Non-Sporting group is such a mish-mosh of breeds. But there are also the subtle cautions offered by announcer David Freese that make me think of gardening: Know your breed and pick the one that’s right for you, and don’t buy into the “fad” or “popular” breeds (e.g., dalmations after “101 Dalmations” came out, or whatever breed wins the WKC). And that brings me to pampas grass (Cortaderia sp.).

Jubata patch in slide area off Hoo-Koo-E-Koo on Mt. Tamalpais

Jubata patch in slide area off Hoo-Koo-E-Koo on Mt. Tamalpais

California’s pampas grasses are two very similar-looking but reproductively different species, and just like irresponsible breeders can churn out sick dogs to capitalize on a fad, irresponsible or ignorant plant breeders can inadvertently introduce pest plants or diseases in trying to create or capitalize on a fad. According to this excellent article in the 2004 Cal-IPC news, pampas grass (C. selloana) was originally brought up from the South American pampas for its striking inflorescences. The white, fluffy plumes are only produced by the female plant; the male plant’s plumes are darker and thinner. So for a while, only female plants were planted and exported, and no spreading could happen without the males. But fads catch on, and inevitably the male plants made their way into the world, as did the similar-looking purple pampas grass (or as I prefer to call it, jubata grass, C. jubata). Jubata grass, nearly opposite the outcross-dependent pampas grass, is apomictic—seeds form from the female ovules without fertilization. This allows it, like the also-apomictic and wind-dispersed dandelion (Taraxacum officinale), to establish new colonies over long distances and take advantage of disturbances.

Most of what we have in Marin is jubata grass; proper pampas grass is mostly strictly coastal, and found in San Mateo and Southern California (although the Richmond-San Rafael Bridge corridor is an excellent spot to see both species side-by-side). Because of its need to outcross, pampas grass can be slower to establish since the winds of chance need to blow both male and female plants within pollination distance. But that also means it may be able to adapt to changes and eventually invade more areas. The hare to pampas’ tortoise, jubata grass quickly covers disturbed and difficult-to-reach sites such as roadcuts and landslides. We try to keep on top of our populations on Tam, and have managed to mostly keep it contained in a few sites and prevent seeding. The good news is, although the seeds are numerous and far-slung—over 1,000,000 per plant traveling many miles on the breeze—they are short-lived, usually only a year. So once the adults are treated and re-invasion of bare ground is minimized, the follow-up is minimal. Better, though, if we’d had an ounce of forethought and prevention a century ago, and not introduced such an aggressive breed.

Don’t plant a pest: Ornamental grasses of the Bay Area region (California Invasive Plant Council)

An aside/post-script: Speaking of capitalizing on fads, a recently invading ornamental (Erigeron karvinskianus) that used to be called “Mexican fleabane” is now being called “Santa Barbara daisy” and people are buying and planting thinking it’s a California native … which it’s not!


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by Andrea Williams

This is installment five of a 12-part series on grasses. Read the previous installment here.

blue wildrye

Blue wildrye (Elymus glaucus)

I know I should like American robins, but I don’t. It’s just that they’re so common. And I kind of feel that way about blue wildrye (Elymus glaucus).

I first learned blue wildrye in Oregon, during those formative summers on a coastal grassland overlooking the mouth of the Salmon River. Being new to grass ID, I really appreciated how obvious it was—four-to-six-foot-tall spires in a foot-wide clump, usually a bluish-green color with short upper blades flagged straight out from the stem. The inflorescence was nice and simple, too, a narrow, bristled spike. No branching, or sterile florets, or measuring or counting veins to worry about. Just blue wildrye, plain and simple. And then I started monitoring grasslands, and I was so over blue wildrye.

Because it was everywhere. So common. And easy to collect, and easy to grow. Just bend the flowering stalks into a bag and “milk” the seeds and the ripe ones slide right out. Then scatter the seeds over a site and next growing season it will be lousy with wildrye. And these are all good things. Like robins. Sharp red breast, jaunty hop, cherry-dew song. But they’re everywhere. So common.

And so it is sometimes: The need for the new, the value we give to rarity overshadows the basic merits of a thing. I just have to remind myself to appreciate and celebrate the common, to see with new eyes instead of wanting my eyes to always see the new.


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by Andrea Williams

This is installment four of a 12-part series on grasses. Read the previous installment here.

California oatgrass

California oatgrass (Danthonia californica)

I’m sure you’ve heard the phrase “sowing your wild oats,” but did you know that California wild oats (aka California oatgrass, Danthonia californica) is the grass that loves you back? And they have a secret seed to sow?

I grew to know California oatgrass in Oregon, when I spent my summers on a coastal grassland studying the habitat of the threatened Oregon silverspot butterfly. At first I just liked how obvious it was, three fat spikelets and a little eyelash winking at you where the grass blade met the stem. It wasn’t until my time at Redwood National and State Parks that I appreciated the ingenious strategy this grass employs in reproduction. And it wasn’t until last month that I fully appreciated just how hardy and long-lived California wild oats can be.

Most grasses, California oatgrass included, reproduce through wind-pollinated flowers that turn into seeds; think wheat or rice grains. But oats, California oatgrass included, are tasty and can be browsed down before they have a chance to become a new plant. California oatgrass has a contingency set of seeds in the base of its flowering stalk. These flowers are cleistogamous, meaning—like nuns in a cloister—they are kept shut away. The flowers self-pollinate inside the stem, and when the upper (chasmogamous, opening, like a yawning chasm) wind-pollinated flowers have ripened into seeds and are ready to drop, the stem itself detaches from the basal clump of leaves. This gave rise to a new dance, the “Danthonia Shuffle,” during a native grass seed gathering expedition. Rather than plucking individual seed heads, you can shuffle your feet through an oatgrass-laden path and once a sufficient number of stems have gathered around your shins, just scoop the whole lot up into a bag! You not only have the seeds that haven’t dropped from the seed heads, but you have the straw and the secret seeds as well!

California oatgass secret seed

California oatgass secret seed

California oatgrass, once established, is a hardy and forgiving plant that tolerates mowing well. It does prefer wetter areas in grasslands, where it mixes with purple needlegrass, blue-eyed grass, and the cheery yellow of California buttercups. On Mt. Tamalpais, our oatgrass tends to have three to five spikelets above a clump of slightly greyish green leaves. On the coast, plants tend to be a little greener. Last month, as I was staffing the California Native Grassland Association booth at the Point Molate Beach opening, I looked down at the mowed-and-trampled ground and saw a little oatgrass eyelash winking up at me from an emerald clump of leaves—California oatgrass had survived decades of people walking and mowing and picnicking and parking on it.

And why is it the grass that loves you back? The arrangement of spikelets matches the hand symbol for “I love you” in sign language.

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by Andrea Williams

This is installment three of a 12-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 12-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 12-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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