Biology Reference
In-Depth Information
Toyon
Salt grass
Pickleweed
Cordgrass
Eelgrass
MHHW
MSL
MLW
MLLW
Upland &
marsh edge
High
marsh
Middle
marsh
Low
marsh
Mudflat
Shallows
Figure 6. Intertidal distribution of representative plants and wildlife. MHHW, mean
higher high water; MSL, mean sea level; MLW, mean low water; MLLW, mean lower
low water. (Data from P. M. Faber and P. Baye, reference profile courtesy Brad
Evans, drawn by Tim Gunther)
low tide. Farther inland, the tides sweep in and out of tidal marshes via
twisting channels. Brackish marshes lie adjacent to freshwater outlets from
the delta or near the mouths of rivers. Managed marshes , oten owned by
duck clubs, can be salty, brackish, or fresh, but are typically operated to
optimize habitat for waterfowl.
The plants that grow in each type of marsh reflect both local salinity
levels and the length of regular inundation by tidal waters. At their inland
edges, tidal marshes are often sprinkled with less salt-tolerant, upland spe-
cies, forming a particularly diverse transitional habitat. Species that use
the bay for one purpose, and retreat to the uplands for another, rely on
wetlands for cover and shelter during their commutes.
Upland areas are high enough in elevation to remain untouched by bay
waters. Here, more than 20 feet above sea level, marine influences are
muted at best. In the estuary's Mediterranean climate, grasslands and oak
woodlands predominate. Creek drainages punctuate shorelines with ri-
parian forest, willow groves, and riverbank habitats that inject splashes of
species diversity to the shoreline.
During the past 140 years, many habitats in the estuary basin have
been converted or degraded to accommodate humans (see p. 105, “His-
Search WWH ::




Custom Search