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.
 

The Outdoor Nature Lab at the Great Valley Museum Takes Shape

For thirty years it was nothing more than a dream, something hoped-for, but never realized for lack of funds. Ten years ago it became a possibility when our country passed Measure E to redevelop the campus of Modesto Junior College. But there were many, many projects, more than the measure could pay for. But there was still enough of a dream that the faculty and museum staff requested that the vacant lot north of our Science Community Center not be developed in any way in hopes that the last of the Measure E funds might be utilized to construct the Great Valley Outdoor Nature Lab (some administrators wanted to put in grass along with irrigation and walkways; we knew if that happened, the lab would never come into being).

The decision was finally made a year or two ago. The last of the funds would be devoted to the Outdoor Lab! Then came the proposals and planning. Then the budget realities and deciding what parts had to be cut. And finally at the end of the summer the construction began.

There was the very fun business of selecting many tons of boulders and watching them get dropped into place. When I left for the holiday break there were only hummocks of dirt but when I returned this week the concrete walkways had been completed. With the boulders in place, the irrigation system could be installed and in the next three weeks or so an entire woodland of native vegetation will be planted.

The greenhouse is coming along, as are the two mock paleontology dig sites. We have hopes of adding a dinosaur to the landscape, a reasonable facsimile of an Augustynolophus Morrisi, the state dinosaur. The first dinosaur ever found in the state was discovered in our county (it was a Saurolophus of some sort, possibly an Augustynolophus). Interpretative signs are being designed.

Many of the children in our region are not able to visit the wild areas that remain in the Great Valley and adjacent Sierra Nevada Mother Lode. The Great Valley Outdoor Nature Lab will be a microcosm of the valley and foothill ecosystem, with native vegetation, native rock outcrops, and a vernal pool. It is our hope that the native birds, reptiles, and other animals will start making a home in our little microenvironment.

It is a marvelous feeling to see a decades-long dream coming at last to fruition. It's an exciting time for us! More updates to come...

Volcanic Violence and California's Most Endangered Habitat: The Vernal Pool Prairie

The green hills of California's prairie barely conceal a horrific violent past. Around 20-23 million years ago, huge volcanic eruptions shook the western part of North America. Ash (pulverized volcanic rock) blasted into the atmosphere in unimaginable volumes, 100 cubic miles or more. Some of the ash was driven into the upper atmosphere, to be spread around the world with the wind currents, but much of it settled in layers that covered tens of thousands of square miles. Living things would have been buried at best, incinerated at worst. Any one of these events would have been a catastrophe. But there were many of them.

Some of the ash clouds rolled off of highlands that once existed in central Nevada and flowed west into California and down the western slopes of the slowly rising Sierra Nevada. These ash deposits are called the Valley Springs formation, and this rock still influences life in the present day.

The ash eruptions subsided, but new volcanoes developed at closer quarters, near or just east of the present-day crest of the Sierra Nevada. An occasional lava flow reached the lower foothills of the Sierra, but more often, it was a volcanic mudflow, or lahar, that came to inundate the landscape. The rocks today are called the Mehrten formation. Numerous animals lived on the resulting river floodplains and lakes, include tremendous six-foot long salmon (with "tusks"), and tortoises the size of their Galapagos cousins. Mastodons, horses and camels wandered the plains, chased by fearful carnivores, including the ancestors to the Sabertooth cat.

The geologic violence subsided, and erosion has subsequently smoothed off the hard edges of the volcanic rocks. In the semiarid climate, it is mostly grass and annuals that grow here, although the occasional oak survives in the barren landscape. The volcanic rocks contributed to the unique habitat that exists here today, providing through the weathering process copious amounts of clay.

Most of the minerals in ash will decay over time into one of the clay minerals. Soils that develop at the surface tend to be clay-rich, or clay may be present just below the surface, forming an impermeable barrier that prevents water from percolating into the ground. Because wind can blow out hollows, and because clay-rich layers can differentially settle, small pools of water may remain after major winter rainstorms. Because the water can't percolate, it doesn't disappear until it evaporates. The resulting ponds are called vernal pools. The pools are one of our more unique and unusual habitats in California.

A large number of species of plants and animals have evolved to survive in this environment that swings wildly from wet to dry within a period of weeks, and many of the species are endemic to the state. Colorful wildflowers bloom quickly in the drying rings of the "shores" of the little ponds, growing and setting seed before the water has completely dried up. The seeds can repose in the soil for years at time when drought dominates the landscape. Frogs and other amphibians may burrow into the soil and estivate (remain inert) for months on end, waiting for the rains to return.

We spent a delightful afternoon out on the prairie last weekend. It's not too hard because our village lies on the edge of the grasslands. We traveled Willms Road south of Knights Ferry near Highway 108. The spring flowers were just beginning to make an appearance following a warm dry February. There had been fears that this was the end of our rainy season, but a number of vigorous storms are on tap for the next two weeks, so the pools may be filling again for awhile.

Many birds call the prairie home. We felt especially lucky to see a pair of Great Horned Owls in a hollow along an ephemeral creek. The Valley Springs formation is soft and easy to excavate, but the holes are architecturally sound.

A Savannah Sparrow favored me with a pose on a fence next to the road. It was the first time I've had a chance to photograph one.

It was also the first time that I captured a Horned Lark. I thought at first that it was a Western Meadowlark, but I realized the markings were all wrong.

The Meadowlarks were certainly out and about, though. We could hear them all along our drive. At this time of year, they're looking for mates, and aren't at all bashful.

It was a beautiful afternoon in a serene "wilderness" (these are really private ranchlands), but we were also chastened by the sight of thousands of acres of new almond orchards that have been planted just to the west. The water for the trees is coming from irreplaceable groundwater aquifers, and when they have been sucked dry, the almonds will die away. In the meantime, hundreds if vernal pools will have been destroyed.

Where the Rivers are "Upside-Down": A Hike to the Stanislaus Table Mountain

Around 10 million years ago, a lava flow surged from a volcano near present-day Sonora Pass in the Sierra Nevada. Composed of latite, but non-viscous like basalt, it flowed off the volcano and into the channel of the ancestral Stanislaus River, eventually flowing close to sixty miles. The river eventually eroded another valley and the lava flow was left relatively intact. The Sierra Nevada rose and tilted westward, and erosion removed the surrounding softer rock, leaving the former river valley as a ridge several hundred feet high. This was the origin of the Stanislaus Table Mountain, an inverted stream.

In this GoogleEarth image, the trail mostly follows the white line along the base, and then climbs the forested slope on the right.

Table Mountain forms a mesa-like ridge around Sonora and Jamestown in the Mother Lode of the Sierra Nevada. A lot of it is on private property, and as such is inaccessible for close investigation. But one portion lies within the boundary of the U.S. Bureau of Reclamation lands around New Melones Reservoir. The Bureau has constructed a trail to the summit, and that's where we were headed today on our Geology Club hike.

The trail is about 1.5 miles in length, and the first mile is a gentle grade through meadows and oak woodland. The grass was still green and wildflowers were reasonably abundant, but it isn't going to last. The soil felt bone dry, crunching under our feet. It's going to be a long, hot summer.

For the last half mile, the trail becomes increasingly steep. It's a climb of several hundred feet to the top of the lava flow. It was hot today, nearly ninety degrees, and I was appreciative that our trail was on the shaded north side of the lave flow. Oak trees provided shade, but also obscured the view but for a few choice moments.

The view provided us with confirmation of our progress up the mountain. But near the top the trail became a near scramble up the rocks. The short-cuts of use were hard to distinguish from the actual trail, as both were so steep.

The scramble was short, however, and we broke out into the barren surface of the top of the inverted stream. It was an alien landscape. Alien in the sense that it was covered mostly with actual native vegetation, unlike the grasslands below, which have been taken over almost entirely by European or Asian invasive grasses. The invasive species cannot compete in this harsh, mostly dry habitat. It was most certainly dry on this day, as we have had few rainstorms since February.

These rocky flats sometimes contain vernal pools and swales, and constitute one of California's rarest habitats. This section of the flow is one of the only protected portions of this type of landscape. The pools exist for only a few weeks at a time in the winter and spring seasons. At least one of the flower species here is found nowhere else in the world. In spite of the intense dryness, a few flowers persisted here and there, including on the shaded north slopes.

The top of the flow was a fine lookout for views in all directions.

The cliffs drop off steeply on both sides. The local casino lies directly below, and the abandoned open pit Harvard Mine lies just to the east.

To the north lies the nearly dry New Melones Reservoir.

It's a strange and wonderful environment on top of the lava flow, one that is quite different than any found elsewhere in the state. We explored the summit area for awhile, had lunch and started down the trail back to the road.

We visited Table Mountain in an entirely different time back in 2011. We arrived in a wet year, and hot on the heels of an overnight rainstorm. It's hard to describe just how different the scene was on that trip. There were pools and rivulets all over the summit area, and hundreds of small waterfalls cascaded over the cliffs. Flowers were everywhere. It was a totally different experience.

Here are a few scenes. For more, check out these posts from 2011:http://geotripper.blogspot.com/2011/03/day-in-fieldday-backwards-on-fun-having.html, http://geotripper.blogspot.com/2011/03/day-in-fieldday-backwards-on-fun-having_22.html and http://geotripper.blogspot.com/2011/03/day-in-fieldday-backwards-on-fun-having_23.html

Oh, Nuts. What a Great Reason to Destroy the Remaining 5% of the Original California Prairie

Vernal swales on the summit area of Table Mountain. These have some similarity to vernal pools on the valley floor but are also different in some important respects. Click on this post for more info.

Word comes today in the Modesto Bee that a local "farmer" has been fined $160,000 and ordered to purchase conservation easements worth $1,000,000 after he oversaw the destruction of 33 acres of prime vernal pool habitat. He was in the process of converting 850 acres of leased grazing acreage to an almond orchard when his tractors "deep-ripped" 380 acres, including the vernal pools. He had been warned to get a ground-working permit from the U.S. Army Corps of Engineers, but he didn't do so. He was confronted by officials on September 12 who stopped the tractors, but the damage had been done. The investor responsible said only that "I want to farm. That's all I want to do". No, he wanted to cash in, pure and simple. He knew he was flouting the law, and the penalty is appropriate.

Vernal swale on Table Mountain above Jamestown in the Sierra Nevada foothills

Vernal pools are one of the most unique aspects of the California prairie of the Great Valley and lower foothills of the Sierra Nevada. Many endemic species thrive in the pools, and they provide an incredible show of wildflowers in the spring (See this post for an example of the richness of the environment). They are a precious resource that deserve protection, and indeed many of the remaining pools are being preserved, at least on paper. They are defenseless against lawless land-developers, apparently.

There is very little of the original California prairie left, no more than five or ten percent. A lot of what is left has already been altered by grazing, but such lands are not getting particularly worse under that form of land use. It seems we hear that this new development or that one will only take only a few more acres, and a few more. Repeat over and over, and the last of the pools will be gone, especially if the politicians go through with their plans to restrict the power of the Environment Protection Agency and other government organizations to do their jobs and enforce the law.

Vernal pool east of Modesto

As the Bee article points out, People can comment on the proposed penalty by Dec. 18 by emailing r9hearingclerk@epa.gov or sending mail to Steven Armsey, U.S. Environmental Protection Agency, Region IX, 75 Hawthorne St., San Francisco, CA 94105. I hope you will consider writing and supporting the penalty. The water pirates are trying to cash in on the almond craze, and this landscape can ill-afford to be abused in this way. The water isn't there for the long term, and the orchards will die. But not before they've pulled every little bit of short-term profit they can.

Read more here: http://www.modbee.com/news/local/oakdale/article4005292.html#storylink=cpy

So many trees, so little water to keep them alive. But profit is profit.

It's a crime that the last vernal pools are being destroyed this way, and it is ultimately for a money-making scheme that is futile anyway. I talked about the groundwater issue a few months ago, and I am cutting and pasting the information below. Water is the ultimate controlling factor that will leave this as a wasted, barren landscape.

From March 14, 2014: The Water Pirates: A Can a Day is All We Ask (plus 107 million gallons)

New orchard on the California prairie

It's a sad and familiar story for California: there is a valuable resource in the ground, free for the taking. There are those who come to exploit the resource, tearing up the land and leaving behind a wake of destruction. There are no laws to control the behavior of the miners, except for a few arcane rules from a previous century. In the end the resource is gone, and so is the chance for any sustainable use of the land for future generations. In the end, it was all about money, which landed in the hands of a few powerful people. It certainly didn't benefit the ones who did all the physical work.

This could describe the effects of the California Gold Rush of the 1850s, but unfortunately it is not. It is a story that is happening right now in my neck of the woods (prairie?), and the worst of the destruction still lies ahead. And right now, there isn't a whole lot anyone can do to stop it. It's not gold, it's water. And despite the fact that gold is worth somewhere around $1,000 an ounce, the water is far more valuable.

Our local paper, the Modesto Bee, has been running a series of reports recently including this one by reporter J.N. Sbranti that should receive much wider exposure. Almonds have become a valuable and profitable commodity these days, and there is a wild rush on to plant as many acres of almonds as possible. In many cases farmers are simply switching from corn or other yearly crops and putting in orchards. The most destructive aspect, however is the planting of some 30,000 acres of almonds and other nut trees on the former prairie and grazing lands east of Modesto adjacent to the foothills of the Sierra Nevada.

The problem with the trees on the valley floor is that one can't let the fields lie fallow in the driest of years like the one we are now suffering through. The trees must be watered or they die, and they require 4 acre-feet of water per acre each year. If the water gets prohibitively expensive, so what? They'll have to pay the price.

California's version of "snow". The almonds are beautiful when they are blooming.

What's worse are those almond orchards in the foothills. They can't be irrigated by normal means, as there is no infrastructure to deliver water there from the local irrigation district. The only source of water is from the ground, and there are few if any rules regarding the use of the groundwater. The large agribusinesses simply buy up the cheap grazing lands, put in the trees, and start pumping vast amounts of groundwater to water them. According to the Sbranti report in the Bee, the 30,000 acres of new orchards are consuming 39 billion gallons of groundwater each year, which is more than is currently pumped for domestic use across the entire county. The groundwater resource is limited, and will likely be depleted in the service of these orchards. When the water runs out, the orchards will die, but the owners will have gotten their cash. All legally of course, and damn the consequences.

It's all well and good to complain about government regulations, but theoretically government exists to watch over the well-being of the citizens. When there is no governance, the pirates take over, and we all lose. There oughta be a law, but I don't hear about anyone working on it. Much too arcane a political issue. At least until the wells run dry...

A Cat in the Bird House? It haz no 'egrets, but I do!

The other day I posted about our discovery of a nearby treasure, a bit of the California Prairie being returned to a "pre-European" condition with the purpose of preserving a viable part of the migratory flyway for birds in the midst of their journeys between the Arctic and the Equator. It's the San Luis National Wildlife Refuge Complex, a fascinating combination of riparian habitats, marshlands, wetlands and grasslands that is both a permanent home for many birds and other animals, and a stopping place for millions of others.

The other day we just followed a short auto trail, but some research told us that the refuge had much more to offer. The park recently added an excellent visitor center, and offers a number of other auto tours and hiking trails. It's not the prime part of the year to see the migratory birds, but there were plenty of other interesting things to do.

The visitor center was quite interesting with lots of interactive displays, including Lucky the resident cat. She was a feral member of the refuge who was hanging out around the visitor center while it was being constructed. When it was finished, the staff seems to have adopted her, and she has a free run of the exhibits. As the staff points out, that as an indoor kitty she has a huge playground, can't eat the native birds, and won't get eaten by one of the resident carnivores.She is quite friendly...

The building has other interesting aspects. It is a LEED (Leadership in Energy and Environmental Design) Platinum building, with a carbon neutral footprint. Solar panels provide 100% of the energy used in the building, and it uses less than half the water of similar sized complexes.

After our visit with Lucky (oh, and the exhibits), we set out on the waterfowl auto tour. Being the height of summer we didn't expect to see many animals. We were the only visitors on the road (and there should be more). As it turned out, we saw a fair number of interesting birds, almost all of them egrets.

I took the picture above without noticing the herd of elk in the distance! The thing about the egrets is that they were wary of our presence and tended to take off quickly, so we tended to point quickly and shoot before they flew off. Like below...

Zoom lenses were handy, which explains the fuzzy look to some of the pictures. That also happened because we dispensed with tripods. There was never enough time to set up before they took off.

Oh, there's another one flying away!

Does a geological connection seem to be missing? I actually do write about other things sometimes, but I'm coming to realize that a place like the San Luis National Wildlife Refuge complex is very geological in nature. It's not just a layer of sediment. The four environments in the complex (riparian, marsh, vernal pools, and grassland) are all related to activity along the ancestral floodplain system of the San Joaquin River, which has recently started to flow through the refuge again due to legal agreements designed to maximize conditions for the migratory birds and to restore the salmon fishery. There was once a complex intermixing of these environments that was destroyed by the diversion of water for irrigation, and plowing for agricultural development. Groundwater conditions changed radically. It is taking a concerted effort at understanding the dynamics of streamflow and groundwater distribution that is making it possible to restore this complex prairie and riparian environment. It's a multi-decade project, with clear progress in many areas. I was impressed with what I saw!

To my local friends who teach: this refuge is just a few miles from Modesto, Turlock, Los Banos, and Merced, and is a perfect destination for class field trips. Kids will be fascinated with the place, both indoors and out.

Next, the big mammals that live on the complex...