Importance:  The interconnected Madison, Firehole, and Gibbon River drainages (click here to view map) have formed the primary study area for Dr. Garrott's research over the past decade.  The study area is home to a resident herd of elk as well as the migratory central bison herd that spends the winter in the drainages.

Primary wildlife:  Two ungulate species, elk (Cervus elaphus) and bison (Bison bison), are abundant in the Madison-Firehole-Gibbon study area and the presence of the wolves and grizzly bears is also established.  A non-migratory herd of approximately 600 to 800 elk remain within the study area year-round where no hunting occurs. The maximum number of bison using the area as winter range has increased from several hundred in the 1960s to over 1,000 recorded in the late 1990s.  Bison migrate seasonally from their summer ranges in the Hayden Valley and Pelican Valley to the east of the study area to winter range in the Firehole, Madison, and Gibbon drainages during fall and early winter.  Between 250 and 1,100 bison have occupied the area throughout the winters during the years of this long-term study.  Together, elk and bison formed the ungulate prey base for wolves in the study system.

The gray wolf (Canis lupus) is the primary predator of ungulates utilizing the upper Madison winter range.  Wolves were first released into the Firehole drainage in the spring of 1996 and radio-collared wolves moved sporadically through the study area that first year.  The Nez Perce pack established the Upper Madison drainages as its winter territory in 1997 and became the resident wolf pack in the study area.  The Chief Joseph pack and other uncollared wolves occasionally move through the area.  Other large predators found in the study area include the grizzly bear (Ursus arctos), black bear (Ursus americanus), and coyote (Canis latrans).  Though grizzly bears are known as effective predators on neonate ungulates during early summer, their impacts on ungulate populations are assumed to be minimal during the winter months since bears hibernate during most of the study period and prey on elk calves during late May to June.  Impacts on ungulate populations by black bear and coyote predation are also considered insignificant.

Description:  The study area consists of approximately 27,000 hectares at elevations of 2,250 to 2,800 meters in the upper Madison River drainages of Yellowstone National Park, Wyoming. The area encompasses three drainages-- the Firehole River north from Old Faithful and the Gibbon River west from the Norris Geyser Basin to their confluence at Madison Junction, and the upper Madison River to the western boundary of the Park.  Extensive high plateaus carved by rivers result in steep canyons and open meadows where valleys broaden. Geothermal features warm many low elevation meadows and streams, resulting in areas of reduced snow cover and free-flowing rivers with unique plant associations that continue photosynthesizing throughout the winter.  The most extensive geothermal features are concentrated in the Upper, Middle, and Lower Geyser Basins of the Firehole drainage, and the Norris Geyser Basin in the Gibbon drainage.  

Paved two-lane roads along the major rivers extend throughout the area.  From Madison Junction the road along the Gibbon River passes through the Gibbon Canyon and Gibbon Meadows and on to Norris for 22 km.  The roads are open to visitors in wheeled vehicles from approximately April 15 to October 31.  From November 1 until the third week in December the roads are closed to all travel except that by Yellowstone personnel.  During this time the roads are not plowed to allow snow accumulation for the upcoming winter season.  Road grooming begins the evening prior to the opening date of the over-snow vehicle (OSV) season--approximately the third week in December.  Roads are groomed nightly until the end of the OSV season in early to mid-March.  The roads are then closed to all visitor vehicles and plowed to the pavement.  During this period travel is restricted to Yellowstone personnel until April 15.

Habitat:  Lodgepole pine (Pinus contortus) dominates the forested area with stands of Engelman spruce (Picea engelmanni), subalpine fir (Abies lasiocarpa), and Douglas fir (Pseudotsuga mensiesii) interspersed.  More than 50% of the forested area was burned during the summer of 1988. Burned areas are characterized by snags and downed trees, Ross' sedge (Carex rosii), elk sedge (Carex geyeri), leafy aster (Aster foliaceus), and regenerating lodgepole pine.  Wet meadows, which occur in the unforested areas along the rivers, are characterized by standing water or saturated soils and grasses, sedges (Carex spp.), and marsh reedgrass (Calamagrostis spp.). Drier meadows are dominated by grasses (Festuca idahoensis, Poa spp.), and sagebrush (Artemesia spp.). The study area contains four major geothermal basins-- Norris, Lower, Midway, and Upper Geyser Basins-- and many smaller geothermal features where snow accumulation is retarded or prevented.  Thermal effluent from these areas keeps the Madison, Gibbon, and Firehole Rivers ice-free throughout the winter.

Weather:  Winter conditions in the Madison-Firehole-Gibbon area are typically severe.  Snow pack begins accumulating in October and averaged 117 days > 40 cm and 36 days > 70 cm at the Madison Junction ranger station (elevation 2,075 m) from 1992 to 1998.  The average start of melt at the Madison Junction ranger station between 1992 and 1998 was early March.  At higher elevations in the study area snow continues to accumulate after snow melt starts in the valleys.  The average start of melt at the National Resources Conservation Service Madison Plateau SNOTEL site at 2,362 m was early-mid April from 1992 to 1998.  Using averaged daily high and low temperatures, winter mean monthly temperatures in the valleys range from 2.5° C in October to -11.0° C in December and January, increasing to -4.2° C in March and 6.5° C in May.

Aerial view of Gibbon River drainage

Gibbon River

Evening Primrose Springs in the Gibbon drainage

The Gibbon River in Gibbon Meadows

Gibbon drainage near Tankers Curve

Porcelain Basin in the Norris Geyser Basin