The Merced River of California: A Place for Wildflowers and Landslides (and Yosemite Valley)

The Merced River is one of California's extraordinary waterways. First and foremost, it is the river that carved Yosemite Valley, which is one of the world's most spectacular valleys. You may be forgiven for thinking that glaciers carved Yosemite Valley, and they certainly had an important role, but it was learned years ago that the heavy-duty work of carving the 3,000-foot-deep gorge was done before the ice ages ever arrived 2 million years ago. The glaciers certainly modified the shape of the valley, but the depth was first achieved by water flowing over stone.

We spent a couple of days in the valley at a time when the crowds are few, the snow is in retreat, but the green of spring is still some weeks away. It was neither winter nor spring, but the waterfalls were full and the birds were becoming more active, and we had a marvelous time. This morning brought a sight we had never seen in dozens of previous visits though: the beginning of a controlled burn. 

The native Americans who first lived and hunted in the valley knew the value of fire. They would regularly set fires to the forest and meadows to clear out undergrowth and maintain the extensive meadows on the valley floor. When the park was established in 1890, fire became the enemy and any hint of a fire was quickly put out. As a consequence the meadows shrank from the original 750 acres to less than 100 today. The forest became choked with young trees, and fuel built up on the forest floor. It was a major disaster-in-waiting. In recent years, the park management has sought to return the valley floor to something resembling the environment that existed prior to European colonization. Some of the activity has involved some controversial logging operations, and the controlled burns can interfere with the experience of visitors, but the eventual changes will be a vast improvement over present conditions.

One of our real motivations for the trip actually involved a different part of the Merced River, the deep canyon downstream of Yosemite Valley. The Merced River canyon downstream of the lowest extent of the glaciers is a different place entirely. The vertical walls of glacially-shaped granite give way to a V-shaped river valley covered by vegetation that often obscures an extensive belt of metamorphic rocks that are hundreds of millions years older than the granite intrusions.

While not as "spectacular" as Yosemite Valley, the canyon is not without scenic wonders. Indeed, for a few weeks in the spring the walls of the canyon can explode into a color palette that puts the gray granite cliffs of Yosemite Valley to shame. Wildflowers like golden poppy, lupine, and fiddleneck and many others can cover the slopes from the river to the canyon rim.

The climax (if it comes; it's been a dry year) lies a few weeks in the future. But here and there, the slopes provided a hint of what is to come.

The redbuds are just getting started with their not-red buds. More of a pink/purple shade if you ask me.

The slopes of the gorge are also an environment adapted to fire. In the Mediterranean climate the winters are cool and wet, and the summers are very hot and dry. Fires have always swept through the gorge, but those of recent years have been particularly intense due to the extended droughts and higher temperatures due to global warming.

Ultimately fires are a necessary part of the environment, but they can seem particularly tragic in the short-term, especially when people are killed or developments destroyed. The wildflowers play an important role in the recovery of the slopes, as they are pioneer species that help rebuild nutrients in the soils that can assist in the return of the shrublands and forest. The seed may lie in the soil for years before conditions are right for germination, and then the barren slopes come alive with color.

The Golden Poppy is a particularly visible part of the wildflower population. It is California's state flower, and it was a great choice because it thrives in many if not most of California's diverse ecosystems. They're common in the Coast Ranges, the Great Valley, the Sierra Nevada foothills, the volcanic landscapes of the Cascades and Modoc Plateau, the mountains of southern California, and in the Mojave Desert (the Antelope Valley Poppy Reserve is spectacular right now, from what I am hearing). They can also grow on California's strange serpentine soils that most plants cannot tolerate.

A final sight were looking for was the Ferguson Slide. The slope at this particular turn in the river was always unstable, but in 2006 the entire slope slide downwards and covered the highway with tens of thousands of cubic yards of boulders. Far more debris remains on the slopes above, and for a time there were fears that a truly massive slide could block the river and form a natural dam with a lake several miles long. A number of "fixes" were considered, and in the meantime "temporary" bridges were built to provide one-way access on the busy highway. Temporary in the sense that they have been there for fifteen years and counting.

In the end they have decided to build an "avalanche shed", but for rocks instead of snow. The cost is in excess of $180 million (which at the time was about the entire budget for Yosemite National Park). Nature doesn't take kindly to attempts at altering the physics of the slope, and some of the first attempts at stabilizing the upper slopes were laughably sloughed off. There was an earlier coating of the fencing material that was destroyed soon after application. They spent several years carting off nearly 150,000 cubic yards of metamorphic rock and have again tried to fence in the slope. It will be interesting to see what happens when the construction of the shed actually begins.

The photo above is the most comprehensive picture I've been able to capture. I made sure to be last in line when the traffic light changed and allowed the line of cars to follow the one-lane road. I lingered a few seconds to get the shot, and hurried along to make sure I didn't run into oncoming traffic on the narrow bridge. 

There are many more stories to tell of the Merced River downstream, where it flows through the Mother Lode, the places where it lies trapped in the waters of Lake McClure and Lake McSwain, the dredge pits at Merced Falls, and the slow journey across the floor of the Great Valley where it ends in the San Joaquin River. Those will come another day!

California's Rarest Ecosystems: The Serpentine Soils of the Red Hills (Part Two of a Two-part Miniseries)

 

Imagine a world turned upside down and inside out. A place where the underworld realm is exposed to view, where all is out of equilibrium. It sounds like the introduction to a dystopian horror movie, but in this case, it is a description of one of the truly rare and unique ecosystems in California: the serpentine soils. 

This is the long-delayed second part of my two-part miniseries on rare ecosystems. Part one on the prairies and vernal pools was published back in April.

The Red Hills Area of Critical Environmental Concern is a rather clumsy name for one of the most unique places in all of California. It comes by the name righteously, as can be seen in the Google Earth image above. The soils have a distinct red-brown color, even though the serpentine-rich rocks they come from are generally green or black in color. And these are truly alien rocks. They are not part of the surface realm; they are the materials of the earth's depths, far below the crust that we live on. The earth's mantle lies at depths of 15 to 40 miles beneath the surface and is composed of iron and magnesium-rich minerals like olivine and pyroxene. These minerals may be stable deep within the earth's interior, but if they are exposed at the earth they are out of chemical equilibrium and subject to rapid reactions with oxygen, water, carbon dioxide, and acids in soils. The iron quite literally rusts during oxidation.

The thing about soils rich in iron and magnesium is that they are poor in macronutrients like potassium and calcite, and include some toxins like selenium or nickel. The vast majority of plants cannot tolerate these chemical conditions. But there are a few.

At the west end of Red Hills the oak woodland gives way to a gray pine-ceanothus scrubland

The change is stark. Driving up Red Hills Road from the west, one passes through typical foothills oak woodlands, with a thick covering of grass. And then just like that the grass disappears along with the oaks. One enters an area dominated by Buckbrush with the occasional Foothills Pine (Gray Pine). In many areas, barely any vegetation covers the rocks at all.

The region was long seen as having no particular value. The ultramafic (mantle-derived rocks) were related to the gold-bearing lodes, but rarely had any valuable ores in and of themselves. Despite the Homestead Act in the late 1800s that sought to give citizens free land in the west, there were no takers in the Red Hills. No useful crops could be grown on the soils, which was a requirement for owning the property. For many decades the Red Hills were used as a de facto garbage dump and shooting range.

By the late 1980s the Bureau of Land Management, the federal agency in charge of the Red Hills area, belatedly recognized the unique nature of the ecosystem here, and declared it an "area of critical environmental concern". Clean-ups were organized, and minimal tourists facilities (trails, parking areas, vault toilets, and a nature trail) were constructed. Today the park (why not just call it a park, after all?) is a local favorite for wildflower enthusiasts, birdwatchers, and hikers, especially in the spring.

So what is the geologic story of this strange and wonderful landscape?

The Mother Lode is famous as the source of the ores during the Gold Rush in 1848-53, and many people know of the association of quartz veins with the gold. What is less known is that the Mother Lode consists mostly of metamorphic rocks like slate, greenstone, and marble, not the granite that is found in the higher parts of the Sierra Nevada. These metamorphic rocks are the twisted and baked remains of sea floor muds and silts, lime from tropical reefs and shelves, and volcanic rock from the oceanic crust. These collections of crustal rocks (called "exotic terranes") were transported across the Pacific Ocean and slammed (in the geologic sense; they moved at maybe 2 inches a year) into the western edge of the North American continent, mostly in the late Paleozoic and Mesozoic eras (the Mesozoic era, from around 251 to 65 million years ago, is best known as the "age of the dinosaurs"). The different terranes are separated from one another by major fault systems.

California Goldfields (Lasthenia californica)

The rocks of the Red Hills were part of the huge fault systems and included slices of the earth's mantle, consisting of the dunite and peridotite mentioned above. The original mantle rocks were mostly metamorphosed into serpentine on their upward journey along the fault systems.

Blue Dicks (Brodiaea) and Poppies

Serpentine (or more properly serpentinite) was declared the California State Rock in the 1960s, in part for its association with asbestos, which is a fibrous crystal form of serpentine. Asbestos was a "wonder mineral" from at least Roman times, as it was fireproof, and could be woven into a fabric. As fire insulation it no doubt saved many lives, but there was a cost. Those who were constantly exposed to asbestos were far more likely to contract a deadly disease called mesothelioma. It is now a cottage industry for people in the business of removing asbestos from older buildings.

There was a political brouhaha in 2010 when some groups tried to change the state rock to something else, but geologists objected on the grounds that it was an appropriate symbol of the state due to the research value of having mantle rocks at the surface, and the value as an ore for other important metals such as chromite (used in armor and stainless steel), and mercury (used original to separate gold from its host ore). The proposed bill was never voted on.

The Red Hills are semiarid with only a few creeks that dry up quickly as the summer progresses. But a few small springs and pools persist through the year and in those pools is an endemic fish, the Red Hills Roach, a distinct subspecies of the California Roach. It is found nowhere else in the world. We saw some of them a few weeks ago during our visit, but the video below is from an earlier, wetter year.

The rest of the photos are some of the flowers we saw this year, some old friends, and one or two new discoveries.

Poppies

Five Spot (Nemophila maculata)

Monkeyflower (Erythranthe sp.)

Bitter root (Lewisia rediviva)

The last flower was one we've not noticed before. It seems to be a Fort Millers Clarkia, but I am open to correction!

Fort Miller Clarkia (?) (Clarkia williamsonii)

There are just a few flowers left in the Red Hills as of last Friday, but to see the spectacular show you'll need to wait until next spring. But...the rocks are always there!

The Red Hills Area of Critical Environmental Concern is in the Sierra Nevada foothills near Chinese Camp off of Highway 120. If you want to learn more, or pay a visit, information about the Red Hills can be found on this BLM website, and the trail and road map can be found here.

Went Looking for Rocks and Birds, Came Back With Flowers and Butterflies

Oh boy, do I ever have a blind spot for learning. I can't learn flowers or butterflies. I'd blame it on age, but I've managed to learn something like 200 bird names in the last three years, so it's not that. Whatever the cause, I headed into the hills of the Sierra Nevada today looking for rocks and birds, but I came home with a bunch of flower pictures with butterflies that I couldn't confidently identify. So I won't try...I'll depend on your help! The comments section is below.

We were headed to Yosemite Valley to see the waterfalls before they dried up (it has been an excruciatingly dry year). We had already missed what was apparently a spectacular Golden Poppy extravaganza in the Merced River canyon downstream of Yosemite, but there were still plenty of wildflowers to be seen, especially on the shady north-facing slopes. But the unexpected delight of the day was the abundance of butterflies on what flowers there were.

One poor individual flew into our car and had a confusing time trying to get nectar from a pillow.

There was even bits of drama with butterflies vying for the best flowers. The one in the pictures above and below drove off several Checkerspots.

I guess if I get tired of trying to identify every bird I see, I'll turn to flowers and butterflies. The thing is, birds are a year-round project. The flowers are ephemeral, and so are the organisms that feed off of them.

There weren't just butterflies in the wildflower fields. I caught the Ladybug below too, and any number of bees and flies.

It was a spectacular day, and not just from the flowers. Look for some new posts on Yosemite Valley as soon as I get the chance!
 

California's Rarest Ecosystems: The Prairies and Vernal Pools (Part One of a Two-part Miniseries)

The lower foothills of the Sierra Nevada are one of the most unique and almost universally ignored parts of California. Caught between the famous and heavily-visited forests and alpine regions of Yosemite's high country and the utilitarian agricultural fields of the Great Valley, the lower foothills are made of soils too poor to be developed, and too "plain" to be noticed by people rushing up the highways to the mountain resorts. For much of the year they seem barren and lifeless. But these prairies are one of the most precious of California's diverse ecosystems.

The prairies of California once extended the length of the Great Valley, a 400-mile-long grassland supporting millions of grazing animals, birds, and predators, including Tule Elk, Pronghorn, Deer, Grizzly Bear, Mountain Lions, Coyotes, Foxes, and numerous rodents, reptiles, amphibians, fish, and insects. In earlier times (more than 10,000 years ago) there were camels, horses, bison, giant ground sloths, Columbian Mammoths, Saber-tooth Cats, and Dire Wolves.

There were also modern-day wolves, and it is ironic and coincidental that a wolf returned this week to the Great Valley for the first time in a century. It is a young male from Oregon who made an epic journey through Modoc County into the Sierra Nevada near Yosemite Valley, and then into the Sierra foothills of Fresno County, and across the Great Valley (including two freeway crossings). At last report it's now in Monterey County (it's wearing a radio transmitter). 

The prairies were covered with native grasses that were quickly replaced by invasive species when European colonizers arrived and started herding sheep and cattle. Farms eventually replaced the ranches, and the remaining prairies, no more than 5% of the original land cover, were relegated to the fringes where the soils were poor and no water was available for irrigation. Those remaining prairies form a belt through the foothills of Sierra Nevada.  A narrow remnant can be found along the Coast Ranges and the Carrizo Plains west of Bakersfield.

The prairie soils in the Sierra Nevada foothills are notably poor in nutrients because they have not been part of an active floodplain in tens of thousands of years, and the fertile components have been leached away, leaving behind reddish iron oxides and thick clays. Differential settling and wind deflation has left small hollows and depressions that collect rainfall during the relatively rare winter storms. The clay prevents the water from seeping underground, so pools will persist for weeks or months at a time. These pools are the basis for one of California's rarest ecosystems, the vernal pools.

The vernal pools are islands of diverse life in the otherwise barren grasslands. Numerous species of plants and wildflowers, amphibians, and invertebrates have evolved to survive the weeks of water and the months of dryness. As the waters evaporate away, one species of plant after another germinates, grows, and goes to seed. The pools are often rimmed in colorful zones of different flowers.

I'm writing about the vernal pools today because the limitations of travel in the times of a pandemic have kept me pretty close to home. I live on the edge of the prairie between the Tuolumne and Stanislaus rivers and I was out there today. A few pools are left, and flowers are blooming across the region. The views are expansive, extending to the snow-capped peaks of the High Sierra.

The pools and plants provide food and cover for multitudes of bugs and other wiggly organisms, so the pools are trafficked by a large variety of birds, and dozens of species can be identified by discerning and observant individuals, and occasionally by me as well. 

I saw a half-dozen American Avocets in one pond a few weeks ago.

The prairies are one of the best places to see the rare and threatened Burrowing Owls. The area around Crabtree, Willms, and Cooperstown Roads are among the most dependable places to see them in our region.

Savannah Sparrows are a common species, and they'll occasionally cooperate with photographers.

The Western Kingbirds seemed to arrive from their winter homes in Mexico all at once last week. I saw none a week ago, and dozens today, including this one that hung about long enough for a picture.

I have no picture, but I came upon a Gopher Snake in the road that was in serious danger of being run over. I stopped, looked at it carefully to make sure it wasn't a rattlesnake, and then I picked it up to put it in a safer spot. I was suddenly reminded of how Gopher Snakes sometime pretend to be rattlers! They can flatten their normally narrow heads into the triangle shape of a rattler, and will strike in a similar manner. I didn't hold it for long...how do you explain to the EMTs that you picked up a rattlesnake that you thought was something else?

If you are lucky enough to live near a California prairie, this is a good time of year to explore them. If you tend to rush through this unique part of the Sierra Nevada and the Great Valley on your way to Yosemite or some other mountain destination, slow down and give these precious and unique lands a quick look. You won't be disappointed.
 

A Day on the California Prairie: Finding the Precious Places Near Home

Yosemite National Park is closed. The coastline is closed. The state parks are closed. Am I complaining? Not in the least. We are facing an unprecedented threat, so we must curtail our freedoms a bit until the scientists and the doctors (and all of their heroic support staff from nurses to foodworkers to custodians) can do their work protecting us. And we must continue to do our part, isolating ourselves from each other, and from the virus itself. I pray that you are able to stay healthy and safe, and if tragedy strikes, that you find peace in some way.

In the meantime, there are a few legal ways to maintain sanity. Exercising in isolation from others near home is one way. If the city parks are crowded, find a deserted road on the edge of town to walk along. It is a way that we can find the precious and undiscovered treasures that have always been just outside our towns. As it turns out, some treasures are ephemeral, lasting only a few weeks.

My town lies on the edge on one of the few remaining largely untouched prairies left in California. These prairies used to extend across the entire Great Valley, but agricultural development has displaced 95% of the grasslands. There are a series of wildlife refuges up and down the valley that protect some of the remaining wildlands or rehabilitated farmlands. The rest of the prairie tends to be found on the margins, in the foothills of the surrounding mountains where the soils are too thin to support agricultural development.

The rainfall this year has been perilously low, with not a drop in the entire month of February. But March and April saw a resurgence in precipitation and the drying sprouts reawakened, and flowers have appeared in abundance throughout the Sierra Nevada foothills.

We took a drive through the prairie that remains between the Tuolumne and Stanislaus Rivers, and were treated with an explosion of color. I'd love to say I was an expert botanist and tell you all the species, but beyond lupines and poppies, my knowledge of flowers is sadly lacking. What I enjoyed today was the profusion of color.

We are living in one of the most challenging times many of us will ever experience short of all-out war. Natural disasters horribly affect particular regions, but there is always help from elsewhere, and there are places of retreat and refuge if an earthquake or hurricane strikes. But this one is a worldwide viral attack, and all we can do is shelter in place until it passes. It's scary, it's dangerous, and many are suffering. I hope there are a few moments of peace and serenity to be found here in these little treasures close to home.