Tidal Basin Provisional Ecological Site Group

Description

Three plant communities occur on this ecological site. They appear along a salt gradient from most to least tidally influenced. These communities are hydrologically driven. A major disturbance that shifts coastal hydrology, such as isostatic rebound, is required to change site hydrology, and as such no transitional pathways are described between the communities.

The first community is comprised of broad expanses of a mosaiced sedgeland. Ramensk's sedge (Carex ramenskii) and Lyngbye's sedge (Carex lyngbyei) are on drier and wetter areas, respectively, of this mid-tidal zone area.

Lower, more frequently flooded areas support a resilient community of creeping alkaligrass (Puccinellia phryganodes), seaside arrowgrass (Triglochin maritima), and goose tongue (Plantago maritima). This community also grows in depressions higher on the tidal flats that are inundated slightly longer.

These first two communities have a broad tolerance to tidal influence and salt tolerance and cover a wider range within the tidal zones. They do not seem to replace each other but rather occur together in varying degrees.

A third community occurs on higher ground. Vegetation consists primarily of halophytic sedges and grass meadows with scrub birch and willow scrub on better drained soils along drainages and on elevated microsites. Tidal flooding is less frequent here than in the other two communities but still occurs during extreme high tides and storm surges. Scrub birch (Betula gladulosa), labrador tea (Ledum groenlandicum), and sweetgale (Myrica gale) are indicators of the slightly higher, drier position within the tidal flats.

Submodel