The dominant plant species include
Juncus gerardi (black grass; no picture available)
- clumps of erect stems up to 70 cm in height
- stems cylindrical and hollow
- flowers on side of stem near top.
Spartina alterniflora (smooth
cordgrass)
- coarse grass up to 2 m in height
- upper intertidal zone and creeks
- can tolerate regular flooding but roots must not be submerged
for long
Spartina patens (salt meadow cordgrass)
- fine grass, up to 60 cm in height
- above usual high tide level
- used for hay to feed livestock
Distichlis spicata (seashore saltgrass)
- fine grass up to 1.2 m tall
-leaves oppositely arranged along stem
- often grows with salt-meadow cordgrass
- tolerates very high salt concentrations, often only plant along margins
of ponds where evaporation has increased salt levels
Atriplex patula (orach or goosefoot or salt bush)
- broadleaf plant up to 50 m in height
- leaves triangular with lower lobes pointing out like a goosefoot
- leaves greyish, caused by fine scales
- 2 kinds of seeds: small and black vs.large and brown
Suaeda maritima (sea blite)
- leaves up to 5 cm long, narrow, rounded, alternate, light green and sometimes
whitened
Limonium nashii (sea lavender or marsh rosemary)
- sprays of bluish flowers, up to 30 cm in height
- basal leaves only, oval-elongate, fleshy
- flower stems with many branches, above level of leaves
- flowers usually aligned along one side of branch
- flowers small bluish, 5 petals, collected and dried for use in flower arrangements
- some concern that population in this area may be overexploited and may be declining
Solidago sempervirens ( seaside goldenrod)
- arching branches with yellow flowers, up to 2 m in height
- leaves fleshy, lance-shaped
- can tolerate saline conditions, but cannot survive long periods
of flooding
Plantago maritima (seaside plantain or goose tongue)
- leaves long , narrow, basal, fleshy
- flowers clustered at end of erect spike
Some of these species (sea lavender, goose tongue, seaside goldenrod) have succulent leaves while other have succulent stems (Salicornia).In fact, these saltmarsh plants are more succulent than their terrestrial relatives. As these plants transpire (i.e., water evaporates from the surface) the salt in
the water remains within the leaves. Therefore, there is a progressive
accumulation of salt in the leaves over time and salt concentration can
reach toxic levels even in plants with very salt tolerant tissues. One
way around this problem is to dilute the salt concentration in the leaves
by storing water in the leaves (i.e., become succulent). Note that because
salt accumulates over time, succulence must also increase over time (plants
in the spring are not as succulent as in the fall).
However, not all the species of saltmarsh vegetation are succulent (e.g., Spartina, black grass, goosefoot, etc.). There is usually
more than one way to solve a problem like excessive salt levels.
Examples:
1. Black grass has disposable leaves; the leaves senesce as soon as salt concentration
reaches a given level and new leaves are produced.
2. Goosefoot uses salt glands to excrete salt onto the leaf surface where it can be washed off by rain. The leaves have a mealy appearance caused by the
presence of salt excreting leaf hairs.
Why there are so many species (in fact we have only pointed out a small
fraction of them)? In other words, what determines species diversity in
an ecosystem?
There are, in fact, many explanations for differences in diversity.
One of these explanations relates to partitioning of the environment among
specialists. It is based on the concept that a species specialized for
a certain environment will be able to outcompete and exclude species which
are less specialized (i.e., a generalist). Therefore the number of species
depends upon the complexity of the environment. A highly complex environment
tending to support a wider variety of species. A salt marsh is a very good
example of how environmental complexity can regulate species diversity.
Because of differences in elevation and tidal movements, there are marked
gradients in salinity and flooding and different species specialize and
dominate on different parts of this gradient.
In the picture below note the zonation of the different species.
