Marshes, Playa Wetlands, Wet Meadows, and Fens - Mountains and Plains: The Ecology of Wyoming Landscapes - page 75

Fig. 5.8. elongated wet
meadow south of centennial,
with Sheep Mountain in the
background. this meadow
is defined by the presence
of shrubby cinquefoil, with
mountain big sagebrush and
scattered limber pine on the
upland. elevation 8,100 feet.

with essentially no plants surround ponds with salinity
greater than about 5 parts per 1,000. Ponds with less-
saline waters support patches of marsh-like vegetation.
Playa wetlands are widespread on the plains and in
the basins of eastern and southern Wyoming. 21 Where
water persists, the plants are mainly graminoids, such as
common spikerush, needle spikerush, threesquare bul-
rush, mountain rush (also known as Baltic rush), and
meadow foxtail. Small forbs also are common, such as
annual knotweeds. Around the depression's edge, where
facultative hydrophytes mix with upland plants, the
soil may lack the characteristic hydric features.

noids and forbs are the dominant plants; shrubby
cinquefoil is common. (figs. 5.8 and 5.9).
Sites that support wet meadows are diverse and occur
from the high mountains to the basins and plains. 23
commonly they are part of riparian landscapes. in the
alpine zone, small meadows occur downslope from large
snowbanks, where meltwater saturates the soil in spring
and early summer. Broad glaciated valleys typically
support a mosaic of wet meadows and fens, with the
meadows on the lower valley slopes and fens on wetter
sites where groundwater discharges. Abandoned beaver
ponds are common sites for wet meadows, which replace
marshes as the ponds fill with sediments. in mountain
meadows, black alpine sedge and mountain sedge are
common at the highest elevations. other species occur
over a wide range of elevations, for example, tufted
hairgrass, mountain rush, small-winged sedge, blister
sedge, and water sedge. common mountain forbs are
alpine leafybract aster, white marsh marigold, Ameri-
can globeflower, and largeleaf avens. Meadow shrubs
include mountain silver sagebrush, shrubby cinquefoil,
and willows—especially diamondleaf willow. Some
meadows have substantial amounts of various mosses,
though they are more common in fens.

Wet Meadows

Wet meadows develop where water tables are at or near
the soil surface in the spring and early summer but
where the water level drops below the surface as the
growing season progresses. Plant materials decompose
when water levels are low and oxygen is more readily
available, which prevents the accumulation of thick
layers of peat. Although wet meadows may not be rec-
ognized as wetlands during part of the year, they have
hydrophytes and the diagnostic hydric soils. 22 Grami-