Friday, March 31, 2017

Plant Life of the Colorado Desert

The Colorado Desert, the portion of the Sonoran Desert that spills over into California, is a wonderfully diverse ecosystem, botanically speaking.  The Sonoran Desert extends across southern Arizona and south into Mexico and Baja California on both sides of the Gulf of California.  In the state of California, we are lucky to claim a little corner of the Sonoran Desert as our own.  The assemblage of plant life in California's Colorado Desert is markedly different from our more northerly Mojave Desert.  The Colorado Desert, like other regions of the Sonoran Desert, experiences two rainy seasons, one in winter and a second at the end of summer.  This allows for a greater diversity of species here than in the adjacent Mojave Desert.

Chollas, with blooming Desert Senna (Cassia armata)

A drive through Joshua Tree National Park allows visitors to experience both desert ecosystems.  The northern part of the park, where its namesake Joshua Trees are found, lies within the Mojave Desert.  This desert is slightly higher in overall elevation, with cooler average temperatures.  The Mojave Desert can receive a small amount of winter snow, while it very seldom freezes in the Colorado Desert.  The southern part of Joshua Tree National Park lies within the Colorado Desert.  An excellent place to see an assemblage of typical Colorado Desert plants is in the vicinity of the Cottonwood Visitor Center, along the Bajada Nature Trail and on the hike to Lost Palms Oasis.

Trail to Lost Palms Oasis

Sonoran Desert plant communities show greater species diversity as well as more variation in plant form than other deserts.  For example, while the Mojave Desert is dominated by acres and acres of evenly spaced Creosote Bush (Larrea tridentata) and Joshua trees (Yucca brevifolia) - both fascinating plants in their own right - the Sonoran Desert supports more layers of desert vegetation, with towering Saguaro cacti (though just a few are within the borders of California), sub-trees such as Palo Verde and Desert Ironwood (Olneya tesota), and a variety of small-leaved shrubs.  (Creosote Bush also occurs in the Colorado Desert, though mixed with other species; its presence is not quite as obvious as it is in the Mojave Desert.)  The Colorado Desert also supports more species of cacti than the Mojave, giving it more of the "typical" desert look.

California Barrel Cactus (Ferocactus cylindraceus)

In addition to cacti, shrubs and sub-trees, the Colorado Desert supports an abundance of wildflowers.  Common species include Desert Sand Verbena (Abronia villosa), Desert Sunflower (Geraea canescens), several species of phacelia, plus numerous species of desert primroses. 

Engelmann's Hedgehog Cactus (Echinocereus engelmannii) with yellow desert primrose (Oenothera sp.)
and purple phacelia

Two rainy seasons allow more species of wildflowers to flourish in the Colorado Desert.  Annual wildflowers that are adapted to respond to several months of light winter rains (like those of the Mojave Desert) as well as those that respond to short periods of intense summer rain (like those of the Chihuahuan Desert) overlap here, both types able to grow and bloom in the Sonoran Desert.

Sand Blazing Star (Mentzelia involucrate)

Desert Chicory (Rafinesquia neomexicana)

If you've just botanized in Death Valley and the Mojave Desert, then traveled to Joshua Tree National Park eager to explore the flora of the Colorado Desert, expect to recognize some familiar Mojave species, like my favorite, Apricot Globe Mallow (Sphaeralcea ambigua).

Apricot Globe Mallow (Sphaeralcea ambigua)

Apricot Globe Mallow (Sphaeralcea ambigua) growing in a desert wash.

Other common (or noteworthy) plants of the Colorado Desert include Ocotillo (Fouquieria splendens), Indigo Bush (Psorothamnus schottii), Chuparosa (Justicia californica), yuccas, agaves, and a number of species of cacti, including the chollas (which may look huggable, but don't get too close!)

Teddy Bear Cholla (Cylindropuntia bigelovii)

A unique habitat in the Colorado and Mojave Deserts is the palm oasis, where western North America's only native palm is found.  Desert Fan Palms (Washingtonia filifera) indicate the presence of water in the desert.  Oases occur along fault zones, where the movement of tectonic plates has pulverized underlying rocks, grinding some into clay.  The crushed rocks and clay act like an underground dam (or impermeable barrier) to force groundwater toward the surface.  Southern California is the best place to visit a fan palm oasis.  There are only 158 desert fan palm oases in North America, and few exist outside of California. 

Lost Palms Oasis, a California Fan Palm oasis in Joshua Tree National Park

As you might have already guessed, fan palm oases provide a luxurious patch of critical habitat for a great number of desert dwellers, humans included.  Desert Bighorn Sheep (Ovis canadensis nelsoni), Coyotes (Canis latrans) and Gambel's Quail (Callipepla gambelii) visit oases, feeding on palm fruit and subsequently dispersing the seeds.  Orioles (Icterus sp.) nest in the "skirts" of the palms, and a species of bat roosts exclusively in these palm oases.

Trail through the Ocotillos

I highly recommend the 7.2 mile round-trip hike to Lost Palms Oasis in the southern portion of Joshua Tree National Park (hike only in the winter or spring).  The trail passes through beautiful Colorado Desert vegetation (including a neat stand of Ocotillos) and leads to a secluded fan palm oasis, tucked at the bottom of a canyon.  A more accessible (though less impressive, in my opinion) oasis can be seen at the Oasis of Mara visitor center, near the northern entrance to Joshua Tree National Park.

Colorado Desert hillside with chollas and blooming Brittlebush (Encelia farinosa)

Wednesday, March 29, 2017

Plant Profile: Ocotillo (Fouquieria splendens)

The Ocotillo, Fouquieria splendens, is splendid indeed!  Although, some might disagree. 

This seems to be one of those polarizing plants: you either love it or you hate it.  It seems difficult not to form an opinion of this prominent Sonoran desert plant, with its cluster of gangly branches reaching into the clear desert sky like a bundle of sticks in a vase.  (Bonus: this makes it an easy plant to identify!)  My opinion is probably not a surprise: I love this plant!  It demonstrates impressive adaptations for life in the hot desert, and its brilliant red flowers provide a valuable nectar source for hummingbirds on their northern migration.

Ocotillo at Joshua Tree National Park

Desert plants have many different strategies for coping with the hot, dry conditions of their habitat.  Some have small hairs on their leaves and stems, called pubescence, which provide shade for the plants' surfaces; others have waxy coatings on their leaves to prevent water loss.  Most desert plants have very small leaves to minimize surface area exposed to drying conditions.  Many desert plants have succulent leaves and stems for storing water, like the well-known members of the cactus family. 

Ocotillo flowers, perfectly adapted for pollination by hummingbirds.

But Ocotillos are not cacti.  They are technically woody shrubs, albeit oddly-shaped shrubs, in their own family (Fouquieriaceae).  The Ocotillo family consists of 11 species, with Ocotillos being the northern-most species.  (Other species are found across the Sonoran desert, mostly in Mexico.)

The way Ocotillos have adapted to life in the desert is somewhat unique.  For most of the year, these plants resemble a giant bundle of dry brown sticks.  But when the rains come, their brown stems turn green and sprout an abundance of tiny leaves.  The leaves grow quickly, turning the plants completely green within several days of the first rain.  Brilliant clusters of tubular red flowers bloom at the ends of long branches, and the plant's transformation is complete.  When conditions turn dry, the plant drops its leaves and returns to its brown resting state.  With the summer monsoon rains common in the Sonoran desert, the Ocotillo springs to life once again, responding with a second flush of green growth.  Ocotillos can go through this green-to-brown cycle several times each season, dictated entirely by the rains.

Ocotillo, with a naturalist for scale. 
These plants can grow up to 20 feet in height and live for 100 years or more!

The ability to turn green in response to rain is a strategy that allows the Ocotillo to take advantage of prime conditions in the desert, and save its energy at other times.  By shedding its leaves during the dry season, the Ocotillo conserves water that would otherwise be lost through the extra surface area. 

Looking up into hummingbird heaven

Visitors to the desert in the spring will be stunned by this plant and its towering wands of red flowers.  Ocotillos bloom in the spring, and sporadically in the summer as rains allow.  The spring bloom coincides with the northern migrations of hummingbirds, which rely on this plant for food as they make their way across the desert.  Other desert animals, such as Verdins (Auriparus flaviceps), carpenter bees, and antelope ground squirrels (which can climb the branches), feed on Ocotillo nectar as well.

In California, look for Ocotillos blooming between March and May in the Colorado desert.  (The portion of the Sonoran desert that extends into California is known as the Colorado desert.)  Two excellent places to see Ocotillos in bloom (along with a host of other neat desert plants) are Joshua Tree National Park and Anza-Borrego Desert State Park.

Sunday, March 26, 2017

Ode To The Wetland: More Than Just A Marsh

I realize this is the third post in a row I've written about California's wetlands.  But bear with me.  They are fascinating ecosystems that are both beautiful and rare (nowadays).  I'll be back to singing my praises of springtime in the desert soon! 

Wetlands and wildflowers at the West Bear Creek unit of the San Luis NWR

Yesterday, Eric and I were able to spend the afternoon exploring San Luis National Wildlife Refuge.  We drove the auto tour routes, hiked the trails and generally reveled in the beauty of spring in the Great Valley. 

In case you've never been out that way, or don't get the chance to visit any of the remaining wild corners of the valley this spring, come along with me on a little tour.

A portion of the waterfowl auto tour route at San Luis NWR

 The San Luis National Wildlife Refuge Complex is composed of several wildlife refuges in Merced and Stanislaus counties.  The San Luis, Merced and San Joaquin River National Wildlife Refuges are open to the public, but the Grasslands Wildlife Management Area, which consists of privately owned land under permanent conservation easements, is not.  Together, these refuges protect 45,000 acres of riparian woodland, wetland, grassland (or upland) and vernal pool habitat. 

This assemblage of distinct habitats represents the San Joaquin Valley's main habitat types.  As such, these protected lands are host to a wide assemblage of plants and animals, including endangered species such as the California Tiger Salamander and the San Joaquin Kit Fox.  The refuge is located within the Pacific Flyway, making it a critical stopover point and overwintering ground for a vast number of migratory birds.  Adjacent to the San Joaquin River, the San Luis National Wildlife Refuge Complex protects the largest remaining network of freshwater wetlands in California. 

Red-winged Blackbird

We begin our tour at the San Luis NWR visitor center, located at 7376 S. Wolfsen Road, Los Banos, off highway 165.  The visitor center gets guests of the refuge oriented, providing interactive displays that allow visitors to learn a little more about the area and its wildlife before venturing out. 

Grassland, beyond the tules.  Note the line of trees marking riparian habitat along the horizon.

Perhaps most obvious to the casual observer is the grassland or upland habitat.  Take the 5 mile drive along the Tule Elk auto tour route to see an example of California's grassland.  Along the way, you will see the refuge's herd of Tule Elk, an endemic species that was nearly lost to hunting and habitat loss in the 1800's.  Animals from this herd are periodically relocated to establish or join other elk herds around the state in an effort to restore the species.

Grasslands make up 75 percent of the refuge complex and are dominated by annual and perennial grasses.  Unfortunately, much of California's native perennial bunchgrasses have been lost and exotic annual grasses from the Mediterranean are now dominant.  Creeping wild rye (Leymus triticoides) and alkali sacaton (Sporobolus airoides) are two of our native perennial grasses.  These perennial grasses are green for a longer period of time each year than the exotic annual grasses we're used to blanketing California's hills in dry gold throughout most of the year.

Upland soils are often saline and alkaline in the San Joaquin Valley, a condition caused by low rainfall and an arid climate.  Plants that grow here must be adapted to these harsh conditions, like salt bushes (Atriplex spp.) and Salt Grass (Distichlis spicata).  Wildlife of the grasslands includes Mule Deer, Desert Cottontail Rabbits, Black-tailed Jackrabbits, voles, California Ground Squirrels and coyotes.  Western Meadowlarks sing from sign posts, Loggerhead Shrikes stake out high vantage points from which to search for prey, and Savannah Sparrows forage for seeds in the grass.  Burrowing Owls make their homes in burrows dug by ground squirrels, and Red-tailed Hawks soar overhead. 

Loggerhead Shrike

The 8-mile waterfowl auto tour route at San Luis NWR meanders through wetland habitats, with stops along the way at three short nature trails.  The first trail, the Chester Marsh trail, crosses a wetland before reaching the San Joaquin River and surrounding riparian habitat.  Riparian woodlands, marked from a distance by a winding line of trees, are dominated by willows, cottonwoods and oaks. 

Riparian woodlands provide a diverse habitat for a number of species, perhaps most notably birds.  High densities of songbirds can be found along riparian corridors, and living trees as well as dead standing snags provide nesting habitat for all sorts of birds.  Waterbirds, like egrets and herons, as well as raptors like hawks and Great Horned Owls nest in large stick nests.  Woodpeckers create nest cavities that are also used by cavity nesting birds, like Wood Ducks, Western Screech Owls, Western Bluebirds and Tree Swallows.  When walking through a riparian woodland, stop often to watch and listen.

Tree Swallow

The majority of the waterfowl auto tour route winds through wetlands.  Some are permanent marshes, dominated by tule reeds, while most other marshes are seasonal wetlands.  The seasonal wetlands are filled with water in the fall, kept full through spring to provide additional habitat for overwintering waterfowl, and allowed to dry out in the summer.  During the winter, Sandhill Cranes, geese, Tundra Swans and a wide array of duck species make their home in these seasonal wetlands.  Important plants of the seasonal wetlands include swamp timothy (Crypsis schoenoides), smartweed, dock and sedges, which provide food for waterfowl. 

Wetland along the Sousa Marsh Trail

The tules and cattails of permanent wetlands provide nesting habitat for non-migratory marsh birds, such as coots, blackbirds, bitterns and Marsh Wrens.  Long-legged shorebirds - American Avocets, Black-necked Stilts, yellowlegs, sandpipers and dowitchers - abound in the wetlands!  Take the time to get out and walk the trails at the Sousa Marsh and Winton Marsh, both near the end of the waterfowl auto tour route.

American Avocet

Hopefully, this little "tour" has broadened your appreciation for the Great Valley and its diverse assemblage of hidden habitats that have been largely lost to development.  The Valley is more than just something to drive through on your way from north to south; it's more than one town after another along the 99 corridor, and it's more than just rows and rows of crops.  It's a rich and thriving ecosystem, begging to be studied, explored, appreciated and protected.

Learn more about the San Luis National Wildlife Refuge Complex at its website:

Friday, March 24, 2017

Wetland Wanderings: Exploring the Great Valley's Marshlands

In my previous post about Elkhorn Slough, I outlined some of the major environmental services wetlands provide.  I also mentioned their intrinsic value: the satisfaction of knowing these wild places exist and are protected, as well as the enjoyment that can be found in visiting such places.  California's Great Central Valley is a beautiful and biologically rich place.  Once a vast prairie crisscrossed by free-flowing rivers, this grassland was historically one of the most productive and diverse grasslands in North America. 

Spring has arrived in the Great Valley!

But the Great Valley was more than a grassland; it also supported a large system of seasonal freshwater marshes, fed by snowmelt from the Sierra Nevada.  The largest concentration of these marshes lined Tulare Lake, in the southern San Joaquin Valley.  As recently as 1900, Tulare Lake was the largest lake west of the Great Lakes.  Surrounding the lake were vast stretches of seasonal wetlands that supported great biodiversity.  Since 1900, rivers have been dammed, water diverted and wetlands drained.  By the 1930's, Tulare Lake and its wetlands were gone.

This is the tale of about 94% of California's freshwater marshes; less than 6% of original marshland has been preserved, and even the remaining wetlands are extensively managed.  But so far, migratory and over-wintering birds seem to have adapted to the new arrangement: fields are flooded in the winter to provide habitat for birds and other wildlife.  Many species have declined, of course, as the Great Valley has been plowed and paved, but many are survivors, clinging to the last wild places.  Some excellent examples of wild lands in California, especially wetlands, are found in our National Wildlife Refuges.

A cloudy spring day at Merced NWR

I will urge you every chance I get to go out and visit one of our local National Wildlife Refuges.  October through April are the best months for viewing wildlife, and offer visitors the most comfortable temperatures.  Beyond May, the managed wetlands will be dry and the birds will have moved on along their natural migration routes.  That being said, we have about a month left in the wetland season.  Wildflowers are blooming, our summer songbirds that winter in the tropics are returning.  Some ducks and winter birds are still hanging around.  (Most of the geese and Sandhill Cranes have headed north already, but there might be a few stragglers.)

A Marsh Wren, singing at its nest.

The wetlands are alive with birdsong: Marsh Wrens, Red-winged Blackbirds, Western Meadowlarks and Song Sparrows fill the air with song.  Get out there and explore!  You never know what you will see!

Yellow-headed Blackbirds - you can't miss them, with their bright coloring and noisy behavior!

A few days ago, Eric and I found a large, noisy flock of probably 80 Yellow-headed Blackbirds (Xanthocephalus xanthocephalus) at the Merced National Wildlife Refuge.  A stunning sight! 

Striking tropical-looking Yellow-headed Blackbirds

Plus, we saw a few Lesser Scaups (Aythya affinis), a handful of Buffleheads (Bucephala albeola) and a large flock of Ruddy Ducks (Oxyura jamaicensis).  Northern Shovelers and Cinnamon Teals were plentiful, as were the lovely American Avocets (Recurvirostra americana).

Elegant American Avocet

Trees bordering the wetlands offer nesting and roosting habitat for a number of songbirds as well as raptors.  Look for American Kestrels (Falco sparverius), Red-tailed Hawks (Buteo jamaicensis), Swainson's Hawks (Buteo swainsoni), and Great Horned Owls (Bubo virginianus); Northern Harriers (Circus cyaneus) are often seen flying low over the wetlands.

You never know "hoo" might be watching you when you venture into the wetlands!

If you're interested in mammals, the Merced and San Luis National Wildlife Refuges offer habitat for the endangered San Joaquin Kit Fox (Vulpes macrotis).  More commonly seen are Desert Cottontails (Sylvilagus audubonii), Black-tailed Jackrabbits (Lepus californicus) and Coyotes (Canis latrans).  The San Joaquin River NWR is home to North American River Otters (Lontra canadensis) and North American Beaver (Castor canadensis).  And of course, let's not forget the impressive herd of Tule Elk (Cervus canadensis nannodes) at the San Luis NWR.

Black-tailed Jackrabbit, hoping to escape detection by blending into its surroundings.

Take a little drive this spring and explore a wetland near you.  To find your nearest National Wildlife Refuge, visit for a detailed map.  But of course these aren't the only places you can go to revel in nature!  Spend a morning along a river, hiking a trail, or even exploring your own property or neighborhood park.  Small pieces of wilderness turn up everywhere when we take the time to look for them.

Tuesday, March 21, 2017

Elkhorn Slough: An Ecological Treasure in Central California

Elkhorn Slough, near the town of Moss Landing on the edge of California's Monterey Bay, is truly a special place.  The slough, or estuary, winds through 7 miles of freshwater and tidal salt marshes.  The Elkhorn Slough National Estuarine Research Reserve (ESNERR) protects 1,700 acres of habitat, while the California Department of Fish and Wildlife protects even more land in the area.  Together, the Nature Conservancy and Elkhorn Slough Foundation have set aside 3,500 acres of the watershed for preservation. 

However, the greater Elkhorn Slough watershed encompasses 45,000 acres.  This means that any water that falls as rain, is applied to agricultural fields, or runs off city streets within those 45,000 acres finds its way into the Elkhorn Slough.  The implications of this is that water running into the slough from the surrounding watershed is often contaminated with agricultural chemicals, motor oil and other toxins.  What's a slough to do with all those nasties?  Certainly they aren't good for the sea otters!

Elkhorn Slough is California largest remaining tract of tidal salt marsh outside of the San Francisco Bay (and much of the San Francisco Bay's tidal salt marsh has been lost to development).  It supports a great deal of biologic diversity.  135 species of aquatic birds can be found here (not counting others, like songbirds and raptors in surrounding areas) and around 200 additional species of birds stop here during their annual migration.  The slough is home to 550 species of marine invertebrates and 102 fish species. 

Though invertebrate species are typically not the most glamourous creatures out there, they form the critical base at the lowest levels of the food web.  Other animals depend on them for food.  Without the insects and the marine invertebrates, the ecosystem would collapse.  More familiar residents of Elkhorn Slough include California Sea Lions, Harbor Seals, Southern Sea Otters. 

Estuaries in California have been largely lost to development (something like 90% are gone), and as a result a high number of threatened and endangered species are found in these special wetlands.  Elkhorn Slough alone is home to two dozen species that are classified as rare, threatened or endangered. 

Three of the United State's top ten most imperiled habitats are found within the Elkhorn Slough watershed.  These habitats are freshwater marsh, maritime chaparral, and the most biologically diverse grassland in North America, the coastal prairie.

In addition to providing habitat for a vast array of species, the slough provides a number of environmental services.  Estuaries like Elkhorn Slough act as a buffer between land and sea.  The assemblage of native vegetation helps to prevent erosion, and the tidal marshes protect surrounding land from floods by capturing excess water and releasing it slowly. 

And remember those toxins we talked about before?  The chemicals and oils and other nasty things that enter the slough from the surrounding watershed?  Wetlands of all types act as filters to remove toxins and restore water quality.  Plants in the wetlands absorb excess nutrients (nitrogen and phosphorus) from fertilizer runoff, preventing explosions of algae growth which use up all available oxygen in the water and lead to the eutrophication of the ecosystem.  Other wildlife subsequently dies off in such conditions from lack of oxygen.  Aquatic plants trap sediments which often contain pollutants such as heavy metals.  The contaminated sediments are trapped and held in place at the bottom of the wetland.  The study of wetlands and what eventually happens to these sediments is on-going; for now, it seems safe to assume that it's best not to disturb wetland soils.

Wetlands also sequester (capture and store) a large amount of atmospheric carbon, even more than their temperate forest counterparts.  Large amounts of blue carbon, carbon captured by oceans and coastal ecosystems, can be stored in coastal wetlands for two main reasons.  First, most of these plants have a high growth rate, each year producing a substantial amount of new growth that requires plenty of carbon dioxide.  Second, when wetland plants die, they decompose very slowly, buried underwater in the largely anaerobic soils (lacking oxygen) of the wetland.  Since decomposition releases carbon back into the atmosphere, carbon is stored for a much longer period of time (hundreds, perhaps thousands of years) in wetlands than in terrestrial ecosystems where decomposition happens at a much faster rate.

If that's still not enough to convince you of the value of these beautiful places, visit Elkhorn Slough, or any other wetland habitat, and see for yourself.  The intrinsic value of wetlands must be seen and felt.  Elkhorn Slough offers visitors a chance for outdoor recreation and relaxation.  Paddle a kayak, hike the trails, watch the terns diving into the water, or sit quietly and contemplate the beauty before you.

Visit Elkhorn Slough's website to learn more:

Monday, March 20, 2017

Plant Profile: Beavertail Cactus (Opuntia basilaris)

Last spring on our desert odyssey, the first glimpse I got of Beavertail Cactus (Opuntia basilaris) in bloom was from a moving vehicle - while I was driving.  It was really just a flash of brilliant pink out of the corner of my eye, a bright splotch of color amongst the creosote scrub.  But I knew right away what plant produced those beautiful blooms.  If we had seen no other wildflowers, I think the Beavertails alone would have made the trip worthwhile! 

From first glimpse, I was smitten with the Beavertail Cactus.  Its brilliant pink rose-like flowers are about 3 inches in diameter, with lovely ruffled petals.  They bloom from March to June; as you can see from all of the buds in these photos, the blooms were just beginning to open when I photographed them last March. 

The Beavertail Cactus gets its common name from the shape of its wide, flat succulent stems, which are reminiscent of the shape of a beaver's tail.  The gray-green stems are jointed, dotted with clusters of tiny reddish bristles (called glochids), and grow in clusters.  This plant is low-growing, up to about a foot in height, with a spread of up to six feet in large specimens.

The Beavertail Cactus grows throughout the Mojave and Sonoran deserts, in southeastern California, southern Nevada, western Arizona and southwestern Utah.  It can be found on dry, rocky or gravelly desert slopes with very sharp drainage, at elevations between 300 and 6,000 feet.

Like other members of the Opuntia or prickly pear genus, the flowers of the Beavertail Cactus are more than beautiful; they develop into edible fruit that is an important food source for many animals, as well as people.  The flowers are frequented by a variety of pollinators, and are of special value to our native bees.

Sunday, March 19, 2017

Hiking Trails: The Rings Trail, Mojave National Preserve

Mojave National Preserve is a hidden gem in California's Mojave Desert, located roughly south of Death Valley National Park and north of Joshua Tree National Park.  The preserve's website and brochures claim "Desert solitude in Southern California," and that is an accurate statement!  While tourists and weekenders from L.A. are waiting in line at entrance stations and jostling for available campsites at Death Valley, Joshua Tree, and Anza-Borrego Desert State Park, hikers, campers, naturalists and solitude-seekers will find the peace they seek at Mojave National Preserve.
The preserve is home to Bighorn Sheep (Ovis canadensis) and endangered Desert Tortoise (Gopherus agassizii).  Its 1.6 million acres boast a larger Joshua Tree woodland than Joshua Tree National Park, and more extensive sand dunes than Death Valley.  And I was very impressed by the spring wildflower display here! 
The mouth of Banshee Canyon
One of my favorite things to do on any outdoor adventure is to hike - just pack a daypack and head out on foot to see what there is to see.  I find that more often than not, the simplest things really are the best.  So I'm always on the lookout for good hiking trails. 
The Rings Trail at Mojave National Preserve is a short 1.5 mile loop, with just a little excitement built in.  The trail begins at the Hole-in-the-Wall visitor center and descends through Banshee Canyon. 
A portion of the Rings Trail through Banshee Canyon
Hikers scramble down dry falls in the narrow canyon (or up, depending on which way you're traveling around the loop).  A series of mounted rings are bolted into the rocks to make the scramble a little easier.  This is the fun part of the hike!  Feel free to do this section more than once (we did!)
The namesake rings
The trail emerges from the mouth of Banshee Canyon, depositing hikers onto the desert floor with a stunning view of desert mesas composed of volcanic tuff (see the first photo in this post).  At a junction with the Barber Peak loop trail, a left turn takes hikers around the south side of cliffs, past petroglyphs and back to the visitor center to complete the short loop.
Bighorn Sheep petroglyph
It is also possible to connect the Rings Trail with the Barber Peak Trail to make a longer hike (not recommended in hot weather).  The Barber Peak trailhead is also located at the Hole-in-the-Wall visitor center and the 6-mile loop trail circles Barber Peak, to the west of Hole-in-the-Wall campground.
More information on hiking in Mojave National Preserve can be found on their website:
The hiking professor ascending the rings
For those interested in geology (and really, everyone should be!) the formation at Hole-in-the-Wall is noteworthy.  The cliffs are volcanic tuff (ash deposits that were so hot, they solidified or welded into solid rock upon landing), most of which is part of the Wild Horse Mesa Tuff formation.  The holes in the rock were formed by, a) gasses trapped in the ash, according to the sign at the trailhead, or, b) damp pockets in the tuff formation, caused by slight variations in the degree of solidification of the ash, which allowed minerals to decay into small particles that are easily eroded away, according to my geology professor.  I'm not sure what to do about that seeming discrepancy in information.  More research, I suppose is the answer!  In any case, the holes have been further eroded by wind and water, and make excellent nesting sites for cliff-dwelling birds.