Wildflowers of the Sierra Nevada Foothills: Red Hills Area of Critical Environmental Concern

Red Hills Area of Critical Environmental Concern: a big name for a special place in the Sierra Nevada Foothills.  Markedly different from surrounding areas and supporting a unique assemblage of species, this area is considered a biological or ecological island.

Bitter root (Lewisia rediviva)

Driving past the Red Hills area on highway 108/120 west of the junction with highway 49, observant motorists will notice a striking difference between the grassy, oak-dotted hills that provide rangeland for grazing cattle, and the sparsely vegetated rocky terrain of the Red Hills. 

Buckbrush and Gray Pine cover Red Hills

The inhospitable soil of Red Hills excludes the annual (and exotic) grasses of surrounding areas and instead supports an assemblage of scraggly-looking gray plants, including Gray Pine (Pinus sabiniana) and Buck Brush (Ceanothus cuneatus), with an understory of herbaceous plants which put on a striking and unexpected wildflower show in the spring. 

In the spring, Goldfields (Lasthenia californica) carpet the ground at Red Hills.

The difference between the grassy oak savannahs and scrubby Red Hills, one might guess immediately, is a product of geology.

Five Spot (Nemophila maculata)

Most people probably immediately link that precious mineral gold to the Sierra Nevada foothill region, otherwise known as the Mother Lode.  But what many don't realize, is that tucked along the base of the Sierra Nevada mountains is a belt of metamorphic rock - slate, marble and the like - which includes a fair amount of California's state rock, serpentine.  Serpentine rocks and the soils derived from them underlie the unique landscape of Red Hills.

Bird's Eye Gilia (Gilia tricolor) - one of my favorite!  Notice the blue pollen on the anthers - a unique feature of gilias.

To understand the origin of these metamorphic rocks, one must travel back through millions of years of geologic history.  Between 544 and 65 million years ago (during the Paleozoic and Mesozoic eras), subduction was occurring along the western edge of the North American continent as plates converged.  As material from the seafloor, limestone reefs and even parts of oceanic crust was scraped up and "smashed" against the edge of the continent, intense heat and pressure metamorphosed or transformed this material into metamorphic rocks.  Differing occurrences of various minerals account for different types of rock.  For example, rocks from the earth's mantel, which have large amounts of the mineral olivine, form the rock serpentine. 

Bolander's Linanthus (Leptosiphon bolanderi) characteristically shows a slight affinity for serpentine soils.

The Red Hills area includes a large portion of the Tuolumne complex of ultramafic rocks, metamorphic rocks that are unusually high in magnesium and iron, as well as nickel, chromium and cobalt.  These minerals are not conducive to the growth of vegetation (magnesium, for one, causes calcium deficiency in plants); in high enough doses, they are toxic to plants.  Coupled with low amounts of the basic nutrients plants require (nitrogen, phosphorus, potassium), these serpentine soils create inhospitable growing conditions. 

Ithuriel's Spear (Triteleia laxa) is endemic (limited) to California.

 Yet, remarkably, life will always find a way, and a small handful of plants, often referred to as serpentine endemics, have adapted to grow and even thrive in these impoverished soils.  Gray Pine and Buck Brush, while present in other areas, seem oblivious to the unfavorable conditions of serpentine soils, and flourish where other foothill species cannot.  Several plants occur only in the Red Hills area and surrounding Tuolumne County, such as California Verbena (Verbena californica) and Rawhide Hill Onion (Allium tuolumnense).

Blue-eyed Grass (Sisyrinchium bellum)

The first time I visited Red Hills ACEC was on a field trip for a botany class I took at CSU Stanislaus; the second and third visit were also for field trips in other botany classes!  But there is clearly a reason this place holds such appeal for botanists, with its unique assemblage of species found nowhere else sprinkled amongst more widespread species that have managed to eke out existences in an otherwise unfriendly landscape. 

Shooting Star (Primula sp.)

Much like our desert regions, the Red Hills area has been neglected over the years: it was "unproductive" from an agricultural as well as mining standpoint, useful for little else besides a dumping ground and place to recklessly drive off-highway vehicles.  Thankfully, since the early 1990's it has been protected by the federal government and this valuable ecological island will be preserved.

Showy Red Sierra Onion (Allium obtusum)

Spring is undoubtedly the time to visit Red Hills: the creeks are running (in wet years), the wildflowers are blooming.  Goldfields color the otherwise gray hillsides, and it seems everywhere one looks, delicate blooms can be found hiding among rocky outcroppings.

Cream Cups (Platystemon californicus)

About 17 miles of looping trails wind throughout the area, providing ample opportunities for the hiker and the equestrian... during the winter and spring months.  (Conditions become quite desert-like during the long, hot, dry stretch of summer and fall.)  I highly recommend bringing a trail map with you, as trail markers are not always dependable.  A map can be accessed through the Bureau of Land Management's website:

https://www.blm.gov/sites/blm.gov/files/documents/files/media-center-public-room-california-red-hills-acec.pdf


Purple Mouse Ears or Douglas' Monkey Flower (Mimulus douglasii) is a miniscule flower
(the whole plants stands a proud 2 - 3 inches tall) with an affinity for serpentine soils.

For more information on the geology of the Mother Lode region (much, much more information) a geologic guide book titled "Roadside Geology and Mining History of the Mother Lode" is available in PDF form through the Bureau of Land Management, and can be accessed through their website.

 https://www.blm.gov/ca/pdfs/bakersfield_pdfs/field_trips/mother_lode_south/pdfs/2006_part_1_maricopa-jackson.pdf



Comments

Post a Comment

You Might Also Like:

Birds of the Desert: Residents & Spring Migrants

Image
Nearly everyone knows the desert as a barren, desolate land of extremes: high heat, low precipitation; little available food and water; prickly, spiny, unfriendly plants growing in a sea of rocks and sand as far as the eye can see.  But for those who stop and look closer, the desert reveals itself as the beautiful, incredible, mesmerizing place it truly is, teeming with unexpected life. Juvenile male Costa's Hummingbird visiting chuparosa blooms next to our campsite in Anza-Borrego Desert State Park. I particularly love the desert in the spring, when the annual wildflowers, cacti, flowering trees and shrubs are all in bloom.  (I've experienced the desert in the searing 120 degree heat of summer, and the rainy, even snowy cold of winter... and spring wins every time!)  Eric and I just returned from a week in the Colorado desert, exploring the imperiled, accidental Salton Sea (more on that coming soon), the vital wetlands of the Sonny Bono Salton Sea National Wildlife Refu
Read more

A Shorebird Primer: Godwits, Curlews, Willets and Whimbrels

Image
For those of us living in the Great Central Valley, autumn is the time to head to the coast.  Of course, there is no bad time to visit California's magnificent coastline.  But as the heat and haze of summer drag on in the Valley, the sea becomes increasingly tantalizing: September and the onset of autumn bring sunny weather and an abundance of migratory seabirds and shorebirds to our coast. A new birder visiting California's Central Coast will undoubtedly be met with a splendid array of very confusing birds.  Among these are small shorebirds like  "peeps" (sandpipers), Sanderlings and various  plovers .  But the larger birds can be just as confusing, until you learn a few distinguishing features.  Four large shorebirds that are commonly seen (and commonly confused) along California's Central Coast are Godwits, Curlews, Willets and Whimbrels. Marbled Godwit (upper left), Whimbrel (upper right), Long-billed Curlew (center front) The distinguishing featu
Read more

Birding in Adverse Weather Conditions: Wind and Rain

Image
Though I often extol the virtues and merits of winter in the Central Valley , especially when it comes to birding, the whole truth is that we experience "bad" weather also, just like anywhere else.  But even when the winter weather rolls in, the birds are still out there!  And sometimes, despite our best planning efforts, a birding day happens to coincide with crummy weather.   In that case, what's a birder to do?  Usually, we go birding anyway!   Birders far more intrepid than I regularly brave the ice and snow of northern winters to see their favorite birds, so perhaps you should look to them for real tips on winter birding!  For those of us in the valleys of California, the worst weather we see - wind and rain - is really comparatively mild.  Birding on an extremely windy day! I don't know of anyone who actually likes birding in the rain.  But I would argue that birding in the wind is just as aggravating as trying to bird in the rain!   Wind can be utterly infuri
Read more

What's Wrong With This Tree?

Image
If you've spent any time in an oak woodland (and I sincerely hope that you have!!) you may have noticed something odd: strange growths on the branches and leaves of oak trees.  You might wonder if the trees are sick or diseased, or plagued with a dangerous pest. But not to worry; these fascinating growths are a normal part of a healthy oak community.  Spined Turban Gall on Valley Oak, with a bonus gall: the tiny orange sphere to the left of the larger gall might be a gall of the California Jumping Gall Wasp (inconclusive) These growths are in fact galls, and are caused by a variety of cynipid wasps.  Galls form when a wasp lays eggs in a plant's tissue, releasing chemicals which stimulate the plant to use its own tissue to form protective structures around the eggs.  As the insect larvae develops, it feeds on plant tissue from within its cozy gall home.  Galls form on a variety of plants, including alders, poplars, willows and even sagebrush.  But the best known and m
Read more

Joshua Tree Woodlands: A Tale of Sloths, Moths and the Trees that Need Them

Image
In 1844, early California explorer John C. Fremont gave a somewhat scathing review of Joshua trees when he wrote, "...their stiff and ungraceful form makes them to the traveler the most repulsive tree in the vegetable kingdom."  Rather unkind, don't you think?  But when Joshua trees were formally described by scientist William Trelease in the 1890's, he noted that Joshua Trees are "the most attractive of all the Yuccas."  I am inclined to agree with this sentiment, and must disagree most heartily with Lieutenant Fremont! I, for one, adore Joshua Trees, with their whimsical shapes and great ecological significance!  If you struggle with plant identification, the iconic Joshua tree, hallmark of the Mojave Desert, is a good place to start.  With densely spiked tufts protruding from the ends of gangly arms stretched towards the heavens, this looks like a plant straight from a Dr. Seuss book.  Native people called these trees “humwichawa,” and used thei
Read more

Invasive Species: European Beachgrass

Image
Visit a beach in California, particularly in the northern half of the state, and you are likely to come across stands of European Beachgrass ( Arundo arenaria ).  It looks so innocuous, picturesque even, waving in the Pacific breeze and blurring the line between land and sea.  But this grass, a plant you've probably never thought twice about, is much more than it seems.  Innocuous it is not.  European Beachgrass is one of California's most wanted offenders: an introduced, aggressive invasive species. This picturesque photo of the California's Pacific Coast has a secret...  Most people won't notice that the grass seen here is an imposter; it's not native to the area, but a species that doesn't belong in this ecosystem. The main crime this grass is guilty of is being too good at its job.  In 1869, European Beachgrass was planted around Golden Gate Park in San Francisco, and since 1900, it has been introduced to other parts of California's coast in an
Read more