Riparian or wetland communities prosper near year-round streams. Typical moisture-loving plants in this zone include rushes; sedges; colorful deciduous trees such as cottonwoods; and shrubs such as willow, quaking aspen, dogwood, mountain ash, and Rocky Mountain maple. These lush but narrow areas are often home to rare, water-loving wildflowers and provide a transition between aquatic and upland steppe environments. North-facing slopes, which receive less sunlight and thus retain more moisture, are favored by most plants. Several rare aquatic plants thrive in Yellowstone’s hydrothermal areas, such as the Shoshone Geyser Basin.
Semiarid steppe vegetation is primarily scrubby and is dotted by lots of fragrant Big Mountain sagebrush, open woodlands, and more than a hundred species of sparse grasses. Prime, wildlife-rich examples of this habitat occur in Yellowstone’s Hayden Valley, Pelican Valley, and Swan Lake Flats. Conspicuous blooms of wildflowers such as the pungent yellow arrowleaf balsamroot; snow-white, mat-forming phlox; flaming scarlet-orange Indian paintbrush; and pastel lupines and penstemons festoon hillsides in late June and early July.
Aspen grove near Taggart Lake (Trail 35)
Sagebrush-interspersed meadows mark the transition between rolling prairies and the forested montane zone (6,000–9,500 feet). Snow persists at higher elevations until July or August around the highest passes. The resulting short, cool growing season limits the number of plant species. Snowmelt on warmer, south-facing slopes waters hearty conifer (cone-bearing) species, such as Douglas-fir; Englemann spruce, which dominates older forests; and the higher-ranging subalpine fir. Shrubs and berries dominate the damp under-story. If there is a prolonged absence of fire, spruce–fir forests should begin to succeed the currently dominant lodgepole stands.
Subalpine habitat below Rendezvous Mountain in the Teton Range (Trail 42)
Beyond the upper montane zone, the wild subalpine zone (7,500–10,000 feet) continues up to timberline. Isolated spruce–fir stands dominate where snow lingers longest. Short-lived wildflower displays can be fantastic after the spring snowmelt. At higher elevations, such as around Mount Washburn, the nuts of whitebark pine (which is sometimes confused with limber pine) are a favored but erratic source of prehibernation nutrition for ravenous grizzly bears.
Above timberline, the alpine zone (above 9,000–10,000 feet) is reserved for the most robust species of both plants and humans. The exposed meadows and rocky outcrops host bountiful but short-lived wildflower shows in late July and August. Wind-stunted Krummholz trees abide in sheltered areas of southern exposure. More than 200 plant species have been cataloged just beyond Yellowstone’s Northeast Entrance on the untamed Beartooth Plateau, one of the largest swaths of alpine tundra in the Lower 48.
Fauna
Let’s face it: geyser gazing and rambling around alpine peaks aside, a trip to Yellowstone and the Tetons isn’t complete without spotting—and photographing—a root-grubbing bear with her cute yearling cub, a bugling eight-point elk, a drooling moose, or, at the very least, a wallowing bison.
Besides the iconic thermal features that earned Yellowstone its early nickname “Wonderland,” the park’s photogenic wildlife is the main draw for most visitors. Thanks to the successful wolf-reintroduction effort (see page 10), Greater Yellowstone now supports all of the 61 native mammal species it has historically hosted. With such an incredible concentration of charismatic megafauna, these parks are easily among the world’s foremost wildlife-watching hot spots.
The comparison frequently drawn between Yellowstone’s Lamar Valley and the Serengeti Plains in northern Tanzania isn’t frivolous. Both parks grapple with similar issues: managing large, migrating wildlife herds, reducing the spread of disease, curbing invasive species, and coping with ranching and human development in their shrinking buffer zones.
If Greater Yellowstone has a totem species, it’s the great grizzly bear (known as the brown bear, bruin, or Kodiak bear in Alaska). Yellowstone constitutes the heart of its range, which is estimated to have expanded by as much as 40% since 1975, when the 136 remaining animals in the region were listed as threatened under the Endangered Species Act. The rise in grizzly numbers has been a major conservation success story. Current estimates of the park’s population hover around 150, with 717 bruins inhabiting the Greater Yellowstone region in 2016. The region in northwestern Montana around Glacier National Park (the Northern Continental Divide) harbors the only other major grizzly population in the Lower 48, with around 1,000 bears, though there are a handful of grizzlies in Montana’s Cabinet-Yaak region and Washington’s Cascade Mountains. That said, grizzlies currently occupy less than 4% of their original range, and numbers are down from a historical population of 50,000.
Since 2007, the U.S. Fish and Wildlife Service has been trying to delist the grizzly (remove it from the list of endangered species), claiming that the Yellowstone region has reached its capacity. The delisting process has been wrapped up in legal proceedings for the last decade, but the grizzly is expected to be delisted in 2017 and management passed to individual states, with the likelihood that grizzlies will then be hunted for sport in Montana, Wyoming, and Idaho (but not within Yellowstone or Grand Teton National Parks). Critics of delisting say that the long-term genetic health of the grizzly has not yet been secured because bear populations survive only in isolated pockets, separated from each other.
Bison graze in Fountain Flats in the Midway Geyser Basin.
Besides poaching near park boundaries, current threats to grizzlies include a decline in cutthroat trout caused by the so-called whirling disease and illegally introduced lake trout, as well as the blister rust fungus and spread of bark beetles that have been decimating the supply of whitebark pine nuts, a prime source of late-season sustenance for grizzlies. Researchers have found that wolf reintroduction has actually increased the bears’ food supply: since 2000, all wolf-killed ungulate (hooved mammal) carcasses in the Pelican Valley have ultimately been taken over by grizzlies.
Each year, most of the bear sightings typically reported in Yellowstone are in the vicinity of Tower–Roosevelt Junction. Other areas with frequent sightings include Bridge Bay, and from Fishing Bridge to Yellowstone’s East Entrance. Less frequent sightings occur around dawn and dusk near Mammoth, on the north slopes of Mount Washburn, and in the Hayden and Lamar Valleys. In recent years, grizzly sightings have become more common than black bear sightings.
Yellowstone’s abundant, omnivorous black bear, with an estimated population of 500–650, exists primarily in niches not filled by territorial grizzlies. Sightings (and resulting roadside “bear jams”) are common around Tower and Mammoth. Despite their name, their coloration actually ranges from black to cinnamon. Both black bears and grizzlies start denning around mid-November, emerging from hibernation starting in April.
Black bear cubs never stray far from their mothers.
Bear Safety Guidelines
Restrictions in Yellowstone’s 16 Bear Management Areas include seasonal closures, recommendations on minimum party size, and off-trail travel and camping prohibitions. Several trails in this book pass through these areas. No matter where you hike,