Salt Marsh includes the upper-most reaches of the tidal water. Here at the Slough this also includes a salt panne area and some brackish marsh areas where fresh water flows into the slough and forms a mix of salt and fresh water habitats. These marshes serve an important function in both the uptake of nutrients and to buffer shoreline erosion.
The main salt marshes are covered with plants and occur at elevations of approximately 4.6 feet to 5.3 feet above MLLW. The majority of a salt marsh habitat is a flat plain, although some areas near tidal creeks, ponded areas, and upland transitions have more varied topography and greater plant diversity.
The salt panne areas are bare patches within the high salt marshes. Salt pannes are typically flooded in the winter (with rain and extreme tides) and dry with a salty crust in the summer.
The tidal brackish marsh occurs where saltwater is diluted by freshwater during much of year, salinity ranges between 0.5 to 18 ppt, and it floods extensively (or is in shallow water). The plant and animal species are particularly adapted for a range of saltwater to freshwater conditions. In Elkhorn Slough, most of the tidal brackish habitat currently occurs in sites behind water control structures.
The tidal marsh-upland ecotone areas occur where tidal marsh transitions to upland vegetation. This transition zone may be inundated only on extreme high tide or flood events. This habitat is typically above the maximum tide elevation and functions as an important high tide refuge for tidal marsh species.
More about the marsh-upland ecotone:
We are currently featuring the following slough life from this habitat:
For a more complete look at the habitats of Elkhorn Slough, we recommend Changes in a California Estuary, available in our Bookstore.
For more about tidal habitats see the Elkhorn Slough Tidal Wetland Plan, Chapter 2.