Fall colors on the Kaibab Plateau

Fall morning on the Kaibab Plateau

Last September as I headed to northern Nevada, I made a stop just north of the Grand Canyon, in a beautiful area known as the Kaibab Plateau.  Although the temperatures were still warm, the aspens had started to change color.  I was hoping to record more elk, as I had at Ashurst Lake (see Midnight Callers).

I arrived in the area in the late afternoon, setting up my tent in the midst of a fir-aspen grove.  The red squirrels were making quite a racket, as they spat territorial calls at each other and dropped fir cones onto the forest floor to stash in their middens.  With the large meadows nearby, it looked like great elk country.  But as I looked around the area, I realized something was missing – elk sign.  No piles of poop, no tracks, no scars on the aspens from them gnawing on the bark.  Had I done my research, I would’ve known that; although elk are commonly seen on the south rim of the Grand Canyon, there are no established populations on the north rim, although rare individuals or small groups do wander through.  So I set up my recorder and crawled in my tent, listening in vain for the sound of elk bugling.

I didn’t hear any elk, but did hear a lot of other sounds.  The squirrels were busy until almost 11 pm.  Bats swooped through, making audible social calls.  A pygmy owl stopped by for awhile, giving its monotonic hoots before moving on.  The squirrels were back out collecting cones before the first hint of dawn.  As the sky slowly lightened, they were joined by Stellar’s jays, Clark’s Nutcrackers, chickadees and a few other birds I didn’t recognize.  As I lay in my tent listening (and recording), a raven flew over on creaky wings, and issued a strange, cryptic call.

After breakfast, I took the dog for a walk on one of the many old logging roads that laced the forest.

Fall color north of the Grand Canyon

Fall color on the Kaibab Plateau

The sunlight danced on the golden aspen leaves, and I stopped to admire stands of baby aspens.  The density of baby aspens, especially with smooth bark, was further evidence that elk were not in the area.   Aspen bark forms a large part of the winter diet of elk, and in areas where elk are abundant the trees are heavily scarred and young aspen may be non-existent.  Large populations of deer can have similar effects, and the Kaibab is famous for an inadvertent experiment in predator-prey dynamics, in which most of the wolves and mountain lions were wiped out, bobcats and coyotes greatly reduced, and the mule deer population exploded, leaving the range extremely overbrowsed.   Long cited as a text-book example of the impacts of predators on prey population dynamics, subsequent research highlighted that other factors besides predation, such as precipitation, cattle grazing, wildfire, and logging, may have had greater impacts on the deer population.  Now, reportedly mountain lions have returned, and the deer are heavily hunted.  At least outside of the Grand Canyon National Park, their impacts were not extensive.

Healthy young aspen stand

Healthy young aspen stand

 

Scars from elk browsing on aspen

Scars from elk browsing on aspen, White Mountains, Arizona

Wolves and aspen

Extirpated from most of the west just after the turn of the last century, wolves have slowly been making their way back.  They were introduced into Yellowstone National Park in the mid-90’s, drawing a flock of researchers to see what impact the return of this important predator would have on the largest, most intact ecosystem in the lower 48.  One of the most interesting results of the wolf reintroduction into Yellowstone has been the effects on the aspen.  For years, the elk had no serious predators other than the occasional mountain lion or grizzly.  Their numbers increased and they had such a significant impact on the aspen that almost all of the living aspen trees dated from around the turn of the century.  As new aspen sprouted, the elk mowed them down.   Wolves are very effective elk predators.  They will occasionally eat other things, but if there are elk in the area, the wolves focus on them, with the result that elk change their behavior.  No longer can they laze around in the aspen stands – the risk of predation is too high there.  They now seek more open areas, where they can see the wolves coming and have a better chance of escaping.  Since the wolves were reintroduced, the baby aspens are back, and so are the willows along the streams.  And so are the beaver, with the result that the streams are healthier.  This trophic cascade was a great illustration of how complex ecology can be and how important intact ecosystems are.  Impacts of wolves on elk behavior have not been as pronounced in other areas, likely because the wolves are too few in number, but it’s also possible that these predator-prey dynamics differ in different habitats and with different complements of predators and prey.  More recent research in Yellowstone and other areas has revealed an even more complex picture.  Aspen recruitment and survival is also related to fire, drought, snowpack, other herbivores (deer, moose, bison, cattle), and even leaf chemistry.  We are just beginning to understand these dynamics, which are difficult and time-consuming to study and require intact ecosystems.  How can we study the effects of wolves on an ecosystem, if we don’t let them reestablish?

Echoes’ Eulogy

Unbeknownst to me at the time I was listening for elk on the Kaibab, a wolf was attempting to do just that.  Wolves were extirpated on the Kaibab more than 70 years ago.  But a lone wanderer was seen in the area just a week or so after I left.  She was a radiocollared wolf, collared earlier near Cody, Wyoming, some 500 miles away.  Dubbed “Echo” in a contest among school children, her radio was no longer functioning.  She wandered though a good chunk of Wyoming and all of Utah before she arrived on the Kaibab.  She was observed a number of times, and some even heard her howl.  How plaintive that howl must have been as she sought members of her own kind: “Hello?  Is anyone there?”  Apparently, she received no answer and started heading back north.  She had traveled 150 miles north by the end of December, when a coyote hunter’s bullet ended her journey.  He claims to have mistaken her for a coyote, but it’s hard to judge the veracity of that statement.  People who hunt coyotes usually are not big fans of wolf reestablishment, so coyotes become scapegoats to make sure wolves don’t set up residency.  He may be protected under the McKittrick Policy, in which prosecutors must prove he knowingly targeted an endangered species.

Wolves are tremendous wanderers, and can repopulate areas rather quickly if left alone.  100 years of wildlife “management” have made it painfully obvious that we cannot replicate the impacts of large predators on prey populations – we simply don’t hunt in the same way.   Predators target the weak and the sick.  We target the big and healthy.  We’ve already lost the Pleistocene predators and large grazers (American lions, dire wolves, short-faced bears, mammoths, mastodons, giant bison, camels, etc.).  We cannot recreate the ecosystems they occupied, but we can at least try to keep our existing wild places healthy, and that means both predators and prey.

For more about wolves, and a recording of a wolf howl, see El Lobo, part 2: Greenfire’s ghost.

Further reading:

Wooley, S.C., S. Waller, J. Vernon, and R.L. Lindroth. 2008. Aspen decline, aspen chemistry, and elk herbiviory: are they linked?  Rangelands 30:17-21.

Mech, L.D. 2012.  Is science in danger of sanctifying the wolf?  Biological conservation 150:143-149.

Winnie, J.A. 2012. Predation risk, elk and aspen: tests of a behaviorally mediated trophic cascade in the Greater Yellowstone Ecosystem.  Ecology 93:2600-2614.

Eisenberg, C., S.T. Seager, and D.E. Hibbs. 2013.  Wolf, elk, and aspen food web relationships: context and complexity.  Forest Ecology and Management 299:70-80.

Recording notes:  Sony PCM-M10 with diy EM-172 capsules in a spaced array.

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