Ecological dynamics
These ecological sites occur in areas which are cooler than the rest of the immediate Puget Trough area, because they occur on sites exposed to prevailing winds from across unprotected marine waters. Typical native plant species include Tufted Hairgrass (Deschampsia caespitosa), Red Fescue (Festuca rubra), Oregon Gumweed (Grindellia stricta), Douglas aster (Aster subspicatus), Fat Hen (Atriplex patula), Pacific silverweed (Potentilla pacifica), Saltgrass (Distichlis spicata), Seaside Arrowgrass (Triglochin maritimum), Lyngby sedge (Carex lyngbyei), Pickleweed (Salicornia virginica), and Seaside plantain (Plantago maritima).
Some disturbance is natural in these plant communities, including: fire, both natural and human caused; soil perturbation resulting from causes such as small mammals, earthworms, root activity; freeze-thaw cycles; and harvest of bulbs and rhizomes; and wildlife grazing. . Disturbances can be reduced or eliminated through actions such as fire control, or cessation of activities such as mowing, soil disturbance, livestock grazing or vehicle access. If no disturbance occurs, this plan community will be invaded by shrub and tree species. Typical shrub and tree species include snowberry, rose, Douglas fire and lodgepole pine. Disturbance will affect the different plant classes in varying ways. Timing of disturbance will also affect shifts in plant communities. The Disturbance Effects on Plant Classes table summarizes some of these effects.
If nonnative species are present in the area, these will invade the site whether or not disturbance is maintained, increased, or eliminated. Their dominance in the community will be affected by the type and intensity of disturbance, as will the dominance of the different plant classes. If disturbance such as tillage, herbicide use, or intensive vehicle traffic eliminates the plant community, then a nonnative plant community will be established, either through planting, or invasion of introduced seral species.
Restoration – It’s possible to reestablish plant communities on suitable soils. Native species can be replanted and the site managed to maintain or increase the percentage cover of these species. The Disturbance Effects table lists appropriate types of disturbance to help establish the desired plant community. If nonnatives are present on the site, there will always be a presence in the community as these species are adapted to a wide range of soils, climates and disturbance regimes. However, the management of disturbance types can affect the balance of species on a site.
The State and Transition Diagram and community concepts are primarily derived from:
MacKenzie, W.H. and J.R. Moran. 2004. Wetlands of British Columbia: a guide to identification. Res. Br., B.C. Min. For., Victoria, B.C. Land Manage. Handb. No. 52.
State 1
Reference State
The soils which support this native plant community typically occur adjacent to marine waters and are affected by extreme high tides and salt-water intrusion. This plant community occurs immediately adjacent to and higher in elevation than Middle Tidal Marsh plant community.
Community 1.1
Tufted hairgrass - meadow barley
Figure 4. Backshore shrub community view of estuary
The Tufted hairgrass (Deschampsia cespitosa) – Douglas aster (Symphyotrichum subspicatu) plant community phase is widespread in estuaries. The Tufted hairgrass – Douglas aster plant community phase occurs in the Upper tidal meadow zone between the backshore shrub communities and the middle tidal marsh, usually in broad and extensive flats. With weakly brackish conditions and irregular inundation.
This community is described as Estuarine Association ED02 in:
MacKenzie, W.H. and J.R. Moran. 2004. Wetlands of British Columbia: a guide to identification. Res. Br., B.C. Min. For., Victoria, B.C. Land Manage. Handb. No. 52.
Table 5. Annual production by plant type
| Plant type |
Low
(lb/acre) |
Representative value
(lb/acre) |
High
(lb/acre) |
| Grass/Grasslike |
1125 |
1500 |
1875 |
| Forb |
375 |
500 |
625 |
| Total |
1500 |
2000 |
2500 |
| Jan |
Feb |
Mar |
Apr |
May |
Jun |
Jul |
Aug |
Sep |
Oct |
Nov |
Dec |
| J |
F |
M |
A |
M |
J |
J |
A |
S |
O |
N |
D |
Community 1.2
Arctic rush - Alaska plantain
Pathway 1.1A
Community 1.1 to 1.2
Increase in period of inundation through processes such as soil subsidence through earthquakes, oxidation of organic matter, or erosion.
Pathway 1.2A
Community 1.2 to 1.1
Reduction in period of inundation through processes such as the accretion of sediment, either from fluvial or oceanic processes.
State 2
Middle Tidal Marsh
The soils which support this native plant community typically occur adjacent to marine waters and are affected by daily high tides and salt-water intrusion.
Community 2.1
Seashore Saltgrass
Community 2.2
Lyngbye's Sedge
Pathway 2.1A
Community 2.1 to 2.2
Increase in period of inundation through processes such as soil subsidence through earthquakes, oxidation of organic matter, or erosion.
Pathway 2.2A
Community 2.2 to 2.1
Reduction in period of inundation through processes such as the accretion of sediment, either from fluvial or oceanic processes.
State 3
Hydrologically Altered State
Community 3.1
G002XN102WA / G002XN202WA
Transition 1A
State 1 to 2
Increase in period of inundation through processes such as soil subsidence through earthquakes, oxidation of organic matter, or erosion.
Transition 2A
State 1 to 3
Diking and artificial drainage.
Restoration pathway 2A
State 2 to 1
Reduction in period of inundation and restoration of freshwater influence through processes such as accretion of sediment and decaying organic matter.
Restoration pathway 3A
State 3 to 1
Restoration through removal of dikes and artificial drainage.
