Geoscience Reference
In-Depth Information
lakes have been constructed to help maintain water
levels for the benefit of wildlife, especially migratory
shorebirds and waterfowl. However, the U.S. Fish and
Wildlife Service has junior water rights; thus, during
times of low streamflow, the refuges may not have
much water available. Mortenson Lake national Wild-
life Refuge was established to protect the endangered
Wyoming toad (see fig. 1.9), known to exist only in the
Laramie Basin.
elsewhere in the basin, the vegetation is more char-
acteristic of sandy soils, such as south of Laramie in the
Red Buttes area and along Sand creek. Small tracts of
dunes can be found, some stabilized by indian ricegrass,
prairie sandreed, sandhill muhly, scurfpea, and silver
sagebrush (see chapter 9). Sand is supplied by the ero-
sion of sandstones in the casper Formation. Periodi-
cally, flash floods carry large amounts of sand from the
mountains.
even more curious than sand dunes are the large
tracts of mima mounds in the basin, some on flood-
plains along the Big Laramie River and some in the
upland grasslands, such as southwest of Laramie (north
of Harmony, and also near Hutton Lake national Wild-
life Refuge, along the road to chimney Rock; see figs.
9.9 and 9.10). the uncertain origin of these features is
discussed in chapter 9.
Fig. 17.11. Ponderosa pine and limber pine on an outcrop of
the casper Formation on the east flank of Sheep Mountain.
Ponderosa pine occurs infrequently in the Laramie Basin, as
this species requires warmer summers with more rainfall than
has been characteristic for the basin.
Fig. 17.12. Riparian wood-
lands east of centennial
along the Little Laramie
River. the trees are narrowleaf
cottonwood. Grasslands and
shrublands extend into the
foothills of the Medicine Bow
Mountains. Limber pine is
common on the mountain
slope in the distance. Photo
by Ken Driese.
 
Search WWH ::




Custom Search