Mountain Meadows and Snowglades - Mountains and Plains: The Ecology of Wyoming Landscapes - page 223

Sagebrush
meadows

Dry subalpine
meadows

Mesic subalpine
meadows common name Latin name

Purple locoweed Oxytropis lambertii X X —

Ross' avens Geum rossii — X X

Silvery lupine Lupinus argenteus X X X

Sulphur-flower buckwheat Eriogonum umbellatum X — —

tall fringed bluebells Mertensia ciliata — X

tufted fleabane Erigeron caespitosus X — —

Western yarrow Achillea millefolium var .

occidentalis

— X X

White locoweed Oxytropis sericea X X —

White marsh marigold Caltha leptosepala — — X

SHRUBS
Mountain big sagebrush Artemisia tridentata ssp . vaseyana X — —

Silver sagebrush (mountain) Artemisia cana ssp . viscidula — — X

Shrubby cinquefoil Dasiphora fruticosa ssp. floribunda — — X

a A dash indicates that the plant is absent or uncommon.

local conditions. Some meadows occur on fine-textured
soils along rivers and streams, where the absence of trees
has been attributed to the soils remaining too wet for
too long in the summe r. 3 e lsewhere, competition from
grasses and forbs may be too great. other meadows are
found where trees are excluded because the soils are not
favorable for tree seedling establishment (fig. 13.2), or
where fires have occurred at high elevations and the re-
establishment of new trees is slow. transitions between
meadows and forests in upland settings can be difficult
to explain, as soil differences often are not obvious. 4
Perhaps the most-studied meadow in the Rocky
Mountain region is cinnabar Park in the Medicine Bow
Mountains (fig. 13.3). early reports suggested that this
dry meadow is slowly moving downwind, with trees
invading on the upwind side (where more snow accu-
mulates) and older trees dying on the downwind edge . 5
However, soil scientists William Doering and Richard
Reider concluded in 1992 that the park was stable.
they suggested, after detailed analysis of soil profiles,
that trees were absent in the meadow because of a shal-
low, 6-inch accumulation of fine-textured surface soil
that provided a better environment for grasses and
forbs. in the adjacent forest, where tree seedlings are

common, surface-soil texture is coarser. the presence
of a distinct stone line under the fine-textured surface
soil in the meadow and its absence in the forest led
Doering and Reider to conclude that the meadow origi-
nated after a severe fire or windstorm, perhaps several
thousand years ago. Subsequent wind erosion removed
much of the exposed fine material but left a layer of
stones (fig. 13.4). Gradually, new deposits of fine, wind-
blown material covered the park. the dryness of the
park probably is caused by two factors: (1) the diffi-
culty of water percolation through the shallow stone
line, with most water held in the shallow, fine-textured
surface soil, where it is readily evaporated; and (2) the
strong winter winds that greatly reduce snow accumu-
lation. Blowing ice and snow also damage the leaves
and stems of young tree seedlings, leading to further
mor ta lit y. 6 Plant water stress in the meadows is sug-
gested by the obvious wilting of many plants during
clear summer days.
Subalpine meadows also persist where summer frosts
are frequent. this seems counterintuitive, because trees
are found nearby. However, because of direct exposure
of the meadows to cold skies at night, frosts at the soil
surface can occur on a third or more of summer nights.