Facilitate tidal exchange to restore/create freshwater marshes from other land uses
Overall effectiveness category No evidence found (no assessment)
Number of studies: 0
Background information and definitions
This action includes actions that facilitate tidal exchange, in order to restore or create marshes from other land uses. The action may be a single permanent one (e.g. breaching sea walls or embankments, installing or widening culverts, excavating tidal creeks) or a reversible one (e.g. opening sluice gates once per day). However, the intervention must affect an area that does not retain substantial characteristics of the target habitat. This could be an upland area (e.g. the thousands of square kilometres of farmland that has been reclaimed from salt marsh in the Netherlands since the Middle Ages; Wolff 1992), an unvegetated wetland (e.g. mudflats), or a wetland other than the target type (e.g. swamp, where the habitat used to be a marsh). “Planned retreat” and “managed realignment” fall within the scope of this action.
Tidal wetlands may be brackish/saline (e.g. mangroves, coastal marshes) or freshwater (e.g. at the upstream end of estuaries, as in the Mississippi, Yangtze, and Elbe rivers; Baldwin et al. 2009). Studies of accidental realignment, such as when coastal defences are breached by a storm, have not been summarized as evidence (e.g. Onaindia et al. 2001; some sites in Williams & Orr 2002).
Related actions: Facilitate tidal exchange to restore degraded marshes; Reprofile/relandscape or Remove surface soil/sediment, both of which can alter patterns of tidal exchange; Facilitate tidal exchange to complement planting.
Baldwin A.H., Barendregt A. & Whigham D. (2009) Tidal Freshwater Wetlands. Backhuys Publishers, Lieden.
Onaindia M., Albizu I. & Amezaga I. (2001) Effect of time on the natural regeneration of salt marsh. Applied Vegetation Science, 4, 247–256.
Williams P.B. & Orr M.K. (2002) Physical evolution of restored breached levee salt marshes in the San Francisco Bay estuary. Restoration Ecology, 10, 527–542.
Wolff W.J. (1992) The end of a tradition: 1000 years of embankment and reclamation of wetlands in the Netherlands. Ambio, 21, 287–291.