Plant Guide : Vegetation Type : Alkali Marsh

An alkali marsh typically has a low input of freshwater and a high rate of evaporation, so that salts slowly accumulate in the marsh. Where water input is highly seasonal, this cycle may be reset annually. In southern California, an estuaries often supports an alkali marsh at the upper end.

In SELER, the wetlands of East Basin are alkaline, supplied with freshwater by Escondido Creek and, to a lesser extent, by La Orilla. Freshwater input is complicated by occasional incursions of salt water from the west, although ocean access was greatly reduced by the construction of Interstate 5 and by the dike just east of the interstate, (a situation that will change with the restoration scheduled to begin in 2017).

The salt composition of an alkali marsh is different from that of a salt marsh, but the ranges of salinities are similar and many species occupy both.  East Basin is a shifting mosaic of vegetation with small pockets of freshwater marsh species developing where and when there is adequate freshwater input. It is not uncommon to find freshwater species such as southern cattails and bulrush thriving next to salt marsh species such as alkali heath and pickleweed.