Coastal Systems - Mudflat / Saltmarsh Succession

Mudflats at the edges of estuaries are frequently zones of net deposition of fine sediment. Over time these may evolve into saltmarsh ecosystems with colonisation by plants that can tolerate high salt conditions and frequent inundation at high tide and exposure at low tide.

A positive feedback loop operates, amplifying the initial deposition as submerged and semi-submerged plants trap more sediment and reduce water velocity leading to increased deposition. Plant life-cycles deposit decaying material on top of which new plants grow, gradually raising the height of the saltmarsh.

As height increases, saline conditions reduce, inundation is less frequent and different seral stages occur towards a climax community. Plant succession occurring in conditions of water is termed a hydrosere. A sub-set occurring in salt (as opposed to fresh) water is known as a halosere.