A Living Kaleidoscope in the Red Hills of the Sierra Nevada Foothills

I always thought that kaleidoscopes were named after someone named Kaleid, but the authoritative source (Wikipedia, of course) indicates that the name is a mixture of Latin terms that translates to "observation of beautiful forms." Today I was observing just that at the Red Hills Area of Critical Environmental Concern. I was also there less than a week ago, and in the manner of a kaleidoscope, it is changing colors. 

The Red Hills host a unique ecosystem quite unlike the oak woodlands of the adjacent Sierra Nevada and Great Valley. The underlying rocks are composed of serpentine and other ultramafic rocks, and the soils are poor in many necessary nutrients, and rich in a number of toxic metals. Few "normal" plants, most notably the grasses and oak trees, can live or grow on these soils. Some plants merely tolerate the soils, and can grow elsewhere (like the Poppies), but others are adapted to living on the soils and nowhere else. 

The foothills are semi-arid, and the seasonal lack of water is another factor in the survival of plant species in the area. But when the water comes, the hills explode with life. We've been in the grips of a horrific drought for the last four years, but this year has brought normal, even above-normal precipitation. In these few weeks of spring we are getting the best wildflower show in years.

We've made three trips to the Red Hills in the last few weeks, and it has changed dramatically with each visit. The first visit was early, and there were just a few splashes of yellow here and there around the main parking area. By the second trip, the yellow flowers had expanded rapidly, with widespread areas covered by Goldfields and Monkey-flowers.

Our trip today revealed a vast expansion of the blue and purple flowers, primarily Blue Dicks (Brodiaea) and Bird's-eye Gilia. They provided a nice contrast to the red and brown rocks (rich in iron).  You can literally think of the iron-rich rocks as rusting; they are actually green to black on fresh surfaces.

The rocks that are ultimately responsible for this wonderful scenery were once important for a different color: gold. The ultramafic rocks were closely associated with the Melones and related fault zones that were the conduits for highly mineralized fluids that worked their way towards the surface around 140 million years ago. As the chemical-rich water approached the surface, minerals precipitated out as quartz veins that hosted the gold that was so eagerly sought by miners. These rocks didn't have the gold, but it was near by. When the ores gave out, this landscape was abandoned and left behind for a century. It was the realm of garbage piles, shot-up abandoned automobiles, and off-road vehicle trackways.

It wasn't until the 1990s that people began to recognize the true value of this unique ecosystem. Volunteers cleaned up the messes, and the Bureau of Land Management reclassified the landscape as an "area of critical environmental concern", which is effectively a park designation. The "goldfields" today are the Goldfields flowers that appear after the rain falls. And all of the other wonderful colors that come just a few weeks later.

The Red Hills Weren't Exactly Red Today: Goldfields in the Gold Fields

If my blog posts seem a bit scattered of late, bouncing from one place to another, well, it's kind of true. On the other hand, there is an occasional theme that runs through many of my disparate posts: California has had more water fall from the sky this year than any of the last five. We have been and still are in the grips of the worst drought in California's state history, and so a season of slightly above average precipitation feels like a miracle of moisture.

This afternoon we paid a return visit to the Red Hills Area of Critical Environmental Concern, a small natural wonder in the foothills of the Sierra Nevada, within the Mother Lode gold belt. The "area" is protected by the Bureau of Land Management, preserving one of California's really unique habitats, the serpentine soils.

A strange thing happens with the landscape close to the park boundary: the grass and oak woodland suddenly gives way to an area of very sparse grass (if any) and no oaks. There are instead Buckbrush shrubs and Gray Pines. The precipitation and sun exposure are the same. The difference is in the weathered rock beneath. Serpentine is deficient in many required plant nutrients, and is rich in some toxic metals. As a result, almost no grass or other normal groundcover plants can survive in such conditions. Only plants that are serpentine tolerant or adapted to thrive in serpentine can survive. As a result, many of the plants here are endemic to California, and at least a few aren't found outside the preserve.

The area once was the realm of target shooters, off-road vehicles, garbage piles, and vandals. It took time for the unique nature of the area to be recognized, and now it has returned to something of its original appearance as the native plants have reclaimed their territory. When the rains come, it explodes with color, including the early season blooming California Goldfields (Lasthenia californica) that we saw today. California Goldfields in the gold fields of California...it's a beautiful sight.

Information on the Red Hills ACEC can be found here: http://www.blm.gov/ca/st/en/fo/folsom/redhills.html

Spring in the Sierra Nevada Foothills, A First Report (and a baby horsie)

It was the first day of April, and we decided to take a drive in the Mother Lode, the gold mining region that makes up the foothills of the Sierra Nevada. We weren't really expecting much in the wildflower department, as it has been a horrendously dry year, and the hills were still brown just a few weeks ago. March brought us a few serious storms so the ground is saturated and flowers are starting to grow, but few have bloomed. I included the picture of the Monkeyflower above because it was the ONLY one I could find. But at least it holds the promise of a colorful flower show in the next couple of weeks.

We headed up a road we've never followed before, Hunt Road out of Milton (and congratulations if you have ever heard of Milton). It was the kind of road so rarely traversed by sightseers that the ranchers look at you long and hard to see if you are capable of rustling their cattle. The road itself has been patched to the extent that the asphalt filling the potholes exceeds the amount of original pavement. But it was a beautiful drive. We climbed the escarpment underlain by the Gopher Ridge Volcanics, composed of the remains of island arc terranes that slammed into the western edge of the North American continent during the Jurassic and Cretaceous periods. Oak trees and the exposures of the metavolcanic greenstone were all around us. We could see the prairies of the Central Valley below and the Coast Ranges on the far side of the valley.

In the rugged terrain near the crest of the ridge we passed a stamp mill left over from the gold mining days. I don't know the name of the mine.

 After crossing the ridge, we entered into the vast meadow of the Salt Springs Valley. It looks like a flood plain filled with alluvium, but it is actually underlain by the Salt Springs Slate, which weathers quickly into a clay-rich soil.

Bedrock exposures stick up here and there, forming the famous "tombstone" rocks. The original mud and silt of the ocean floor has been compressed and hardened into the slate, but at heart these rocks are still clay, and break down quickly. The quartz bearing silt layers are more resistant to erosion.

Roadcuts into the slate reveal the inherent weakness of the rocks. Large slabs have broken off and slipped onto the roadbed. If you look carefully on the lower left, you can see some of the few poppies that we saw today.

We suspected we might find some flowers in at least one spot, so we drove south for 40 miles to the Red Hills "Area of Critical Environmental Concern" (and isn't that a mouthful?). The landscape there is underlain by serpentine and other ultramafic rocks, and grasses are so rare that other plants and flowers provide the dominant ground cover. Even the Red Hills were just beginning to show some color, with just Goldfields carpeting the rocks, and the one Monkeyflower shown at the top of the post.

In a few weeks, this spot will be alive with poppies, lupine, and a myriad of rare serpentine-tolerant flowers. We will be sure to visit in a bit and provide an update.

 Oh, as promised, a baby horse...

Springtime on the California Prairielands: An Update (and gratuitous baby horsie pictures)

We went out to investigate springtime in the California prairielands, up around the margins of the Central Valley just short of the foothills of the Sierra Nevada. There is a pretty sharp demarcation of spring and summer in this Mediterranean climate; the subtropical belt of high pressure shifts north and shuts off the rains coming out of the north, bringing higher temperatures. All the sudden it is dry and hot for six months or so, almost without exception (the exception being the occasional tatters of a hurricane out of Baja California). In those warm days of springtime there is an explosion of life on the grasslands.

The first picture above shows a vernal pool (or a very good representation of one; there were railroad tracks nearby that may have dammed the swale). Vernal pools develop on the very old alluvial fan surfaces of rivers that flowed from the Sierra during the ice ages. The muddy rivers spread all over the plains, but when the glaciers melted away the rivers started flowing with clear water. The faster moving rivers carved deep channels and narrow floodplains that they have occupied for the last 13,000 years. The surfaces above the floodplains are pockmarked with numerous small basins with small interior drainages (caused by wind deflation or differential settling of the soil). The basins are lined with clay that causes water to pond instead of sinking into the soil. The vernal pools are an ecosystem pretty much unique to the Sierra Nevada foothills.

You can see a fairly sharp delineation in the vegetation at the edges of the pools. The normal grasses don't do as well being inundated with water for a few weeks in the spring, and being rooted in solid clay. A number of plant and animal species have evolved to thrive in the unusual environment. The vernal pools have been decimated by urban and agricultural development; they were a major issue during negotiations for the siting of the University of California Merced campus. The one we looked at was in a pasture and had been heavily trampled by cattle.

A lot of flowers were visible. It's pretty amazing that I can identify dozens of minerals without breathing too hard, but I have a mental block when it comes to any flower called something other than Poppy or Lupine. I'm guessing that this beautiful small blue, white, and yellow flower is a Bacigalupi's Downingia, based on a highly sophisticated internet picture search (looking at pictures is one of those things I tell my students not to do when identifying minerals; look at the properties, I say).

I'm a little more sure that the yellow flowers above are Goldfields (Lasthenia californica). There is also some Owls Clover spread along the Goldfields (below). It took a few moments for me to notice the birds perched on the cobbles among the flowers. I am assuming they are juvenile Western Meadowlarks, but I welcome any corrections! I'm about as good with birds as I am with flowers...

I would also welcome an I.D. of the hawk that was soaring above us. I'm afraid I'm flummoxed by any hawks or eagles that don't have red tails...

The prairies that I have come to value so much in recent years are clearly under a threat. For decades the lands have been used for grazing (for better or worse), but as more and more of the prime agricultural lands in the valley have been urbanized, the farms are moving towards the less favorable soils of the foothills. I was shocked by the sudden appearance of hundreds of acres of newly plowed and planted orchards and vineyards.

As promised, there were horses roaming the grasslands, and the mares had recently given birth to foals (I say this because I know Diane and Jennifer, my horse-loving friends, will be all up in arms over the title of today's post). There is an interesting geological connection between the horses and the land here. Most of us know that horses arrived in the "New World" with the Spaniards in the 1500's, but fewer know that the horses were coming home after a fashion.

The ground beneath the feet of mare and foal contains the occasional fossil teeth of horses. Some of the fossils date from as recently as 12,000-13,000 years before the present, the time at which the horses became extinct in North America. Other fossils in older rocks beneath are of smaller horses with different teeth and extra toes. The horses evolved in North America, and there have been dozens of species found as fossils (compared to the three that we have today). Some of them migrated over the Bering Land Strait and thrived in Asia, but they eventually went extinct in America, for reasons that are not clear.

They were a beautiful sight the other day...