The Sagebrush Ocean

It’s no news to anyone who reads my blog that I am fascinated by the Great Basin.  Where some people see brown desolation, I see a complex and intriguing ecosystem.  Actually, many ecosystems, that differ by elevation, latitude, longitude and history.  Lying in the rain shadow of the Sierra Nevada and Cascade Mountains, the Great Basin is dry, relatively austere, and highly corrugated.  Magic lies around every bend, in an assortment of geological wonders  and biological life forms uniquely adapted to cold, wet winters and hot, dry summers.

I recently ran across a book that celebrates this diversity, The Sagebrush Ocean, a natural history of the Great Basin, by Stephen Trimble.   It’s a coffee table-sized book, loaded with beautiful color and black and white images from throughout the Great Basin, many taken during winter and on backpack trips deep into remote wilderness areas.  The book was published in 1989, so is a bit dated (a 10th anniversary edition is available that I’m still trying to get my hands on).  And things have changed in parts of the Great Basin.   The glaciers on Wheeler Peak and the Ruby Mountains are all but gone.  Recent fires have converted hundreds of thousands of acres of sagebrush to scraggly meadows of cheat grass.  Urban areas keep expanding into surrounding wild lands, and many previously untrammeled areas are now lined with the tracks of ATVs.

Trimble’s book focuses on not just the hydrological Great Basin, the watershed where all rivers go to die, but also the biological one.  Big sagebrush is a defining component; where creosote takes over in southern Nevada and Utah describes the southern extent of the Basin, with the northern extent defined by the dividing line with the Columbia River watershed.  The western edge is the Sierras and Cascades, the eastern, the Wasatch and Colorado Plateau.  But within those borders, Trimble finds wonder:

“As you come to know the Great Basin plants, the mass of dull gray shrubs pops into sharp focus.  As your eye sharpens, animals, too, begin to reveal themselves: a dune that seems sterile becomes a metropolis of nocturnal rodents and their predators when you look for tracks at the dawn before the wind whisks them away.

Once you recognize the residents of this desert as distinct characters you begin to notice them repeatedly in the same environments: whitebark pines on windswept mountain ridges, muskrats in marshes, Pinyon jays in piñon-juniper woodland.  You expect to see them there; if they turn up somewhere else, you look for an explanation.

You have developed a naturalist’s eye; you have begun to think like a biogeographer.”

The star of the show is of course, the big sagebrush, Artemisia tridentata.   It’s one of my favorite plants, with it’s lovely blue-gray foliage and heady scent.  It’s rough and scraggly, and a survivor.  It provides food and shelter for an amazing variety of animals, of which the black-tailed jackrabbit is the most numerous, but also including Sage Thrashers, Sage Sparrows, Sagebrush lizards, Sagebrush voles, and more than a thousand species of insects and other invertebrates.

“Few animals make sagebrush the center of their universe in the way chisel-toothed kangaroo rats rely on shadscale.  Least chipmunks live consistently in sagebrush stands, though they eat mostly seeds; sagebrush voles and pygmy rabbits use the shrub as primary food.  But sagebrush’s volatile oils inhibit microbe action in the rumen of hoofed browsers like deer and sheep.  Of large mammals, only pronghorn eat large quantities of sagebrush in winter, and of birds, only Sage Grouse.

In the past, Pleistocene browsers like North American camels and ground sloths may have made better use of the abundant forage.  Though big sagebrush matches alfalfa in protein content and surpasses it for carbohydrates and fats, today most sagebrush browse goes uneaten.”

At the end of June, 2016, as I neared the end of my seasonal journey to northern Nevada, I camped in the mountains south of Ruth, taking a long dirt road into the White Pine range and finding a nice little campsite near the top of the ridge.  I had been chasing thunderstorms all day, but the clouds started to break up at sunset.  Eastern Nevada receives quite a bit more rain than western Nevada, managing to pull in a bit of the Mexican Monsoon.  The extra rain makes a big difference – the habitat is much more lush and green.  The area is thick with elk, mule deer, pronghorn and wild horses.  Because the habitat changes with altitude, the high altitude pine and juniper forests on the mountain tops are isolated from each other – separated by oceans of desert scrub dominated by big sagebrush and shadscale, and salty playas.  Each mountain range becomes an island, unique in its composition of plants and animals.

People visiting the Great Basin often comment on how quiet it is.  Sagebrush seems to suck the sound out of the air.  Of course, it’s almost impossible to get away from the sounds of airplanes, and 4x4s and ATVs haunt even the most remote areas, but between the airplanes and vehicles, a lovely quiet can be found.  The night I spent in the White Pines was very quiet – just the whisper of the breeze through the piñon and juniper trees.  First light was accompanied by soft bird chitters that became louder and more lively as the dawn progressed:

After breakfast and a morning walk, the dog and I resumed our journey west.

“The valleys are bigger than you ever remember, and so are the mountains that bound them, each one popping up sequentially from below the horizon – a landmark.  The basins feel more like oceanic fjords (temporarily dry) than valleys.  There appears to be nothing in them, just a low growth of black sage and grass, with less conspicuous plants next to the playas.  Every few miles a grove of cottonwoods and poplars up against the foot of the range marks a ranch, situated where the creeks flowing from the mountains can be tapped before they dissipate into the basin.  And here and there a mining operation makes raw the mouth of a canyon.  Nothing else.  That’s all.”

Trimble, S. 1989.  The sagebrush ocean, a natural history of the Great Basin.  Univ. of Nevada Press, Reno.

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