Wasatch and Uinta

Soft-bodied fossils, tree clones, and the California Trail

I.                    Map Focus Area: 40 to 43 degrees North, 110 to 112 degrees East

II.                 Countries and Subdivisions (States):  United States (Idaho, Utah, Wyoming)

This post includes the Uinta Mountains, northern Wasatch Mountains, and adjoining high plateaus to the east.  The World Wildlife Fund ecoregions are Colorado Plateaus (NA1304), Wasatch and Uinta montane forests (NA 530), and Wyoming Basin (NA 1313). 

III.               Wasatch and Uinta Montane Forests (NA 530)

The Wasatch and Uinta montane forests are found in southeastern Idaho, central and northern Utah, and southwestern Wyoming.  A forest of conifers is found along the north-south trending Wasatch and the east-west trending Uinta Mountains, but the diagnostic species is probably Gambel oak.  Conifers include ponderosa pine, Douglas-fir, subalpine fir, lodgepole pine, and Englemann spruce.  Forests of oak and evergreens line the canyons and peaks of the Wasatch Mountains east of the Great Salt Lake and Utah Lake.  Above 11,000 feet, mostly in the Uinta Mountains, is an extensive area of alpine meadows, rockland, and talus slopes which was glaciated.  From 10,000 to 11,000 feet in the Uinta range is a subalpine forest zone, with glaciated basins, deep canyons, and lakes.  Below the 10,000 foot elevation in the Uinta range is a zone of Douglas-fir, ponderosa pine, lodgepole pine, and aspen parkland.  This is also an area of rugged terrain and deep canyons.  The Wasatch forested area is actually fairly small, consisting of Douglas-fir and aspen parkland.  Most of the Wasatch consists of semiarid foothills with pinyon-juniper, sagebrush, mountain mahogany, and Gambel oak.  There are also extensive wide deep valleys east of the Wasatch front where sagebrush grows.  This includes areas around the Strawberry Reservoir (see), Deer Creek Lake (see), Rockport Lake (see), the Weber River near Morgan, Pineview Reservoir (see), and Sheep Creek. Other similar montane valleys are south of the map area in central and southern Utah.

Only rarely are soft parts of animals fossilized.  There are about 50 known Cambrian soft body localities, the most famous of which is the Burgess Shale in Yoho National Park in British Columbia.  There are three sites in Utah.  In the Wellsville Mountains Wilderness (see) is a 513-million-year-old rock formation, the Langston Formation, which contains arthopods, algae, and jellyfish (University of Kansas 2008).

The characteristic aspen parklands of the high elevations in the Wasatch Mountains are noted for fall color.  Although widely distributed through the Rocky Mountain region, it is in the Wasatch that the aspen has achieved near-immortality.  This is of interest because botanists rarely observe successful seedling establishment in this region.  Seedlings typically wither and die before their roots reach a reliable water supply in this drought-stricken area.  To answer the question on why aspen is so abundant, botanists studied aspen stands in the Wasatch Mountains.  Like many hardwoods, aspens have the ability to sprout from roots and produce clonal individuals.  In fact, aspens are able to create entire ‘forests.’  One aspen clone was found to cover 43 ha and contain more than 47,000 individual stems.  Clones like this could be as much as 10,000 years old.  Clonal reproduction is thought to be more common in arid environments (Mitton and Grant 1996).

IV.               Colorado Plateau shrublands (NA 1304)

The Colorado Plateau shrublands ecoregion of Utah is a high elevation semiarid plateau noted for its canyons carved in sandstone.  Vegetation is pinyon-juniper with some lodgepole pine and aspen at higher elevations.  From the Starvation Reservoir upstream is an area of benchlands and canyonlands along the Strawberry and Duchesne Rivers.  Only a small portion of the Colorado Plateau is on this map, in the southeastern corner. 

V.                  Wyoming Basin shrub-steppe (NA 1313)

The Wyoming Basin shrub-steppe of southeastern Idaho, northeastern Utah, and Wyoming is high open arid country vegetated with sagebrush, wheatgrass, and fescue, found in this map area north of the Uintas and including the upper Bear River and Green River.  It is noted for remnant white-tailed prairie dog colonies.  Wet, flat valleys are found at a number of places in this ecoregion.  They are maintained as wetlands due to a high water table and have vegetation of willow-alder, cottonwood, sedges, and rushes.  Large areas of wet valleys are north of Bear Lake in Idaho, along the Bear River Valley in Utah and Wyoming, around Pinedale and the upper Green River in Wyoming, and along Blacks Fork in Wyoming.  Isolated dry mountain ranges are found in western Wyoming in the area around Fossil Butte NM.  East of the isolated dry mountains are areas of more rolling sagebrush steppe and salt desert shrub basins, consisting of playas and sand dunes and vegetated by shadscale, greasewood, and saltbush.

Further information on parks, public lands, and nationally significant sites in these ecoregions can be found at sites.google.com/site/enviroramble.