Types of saltmarsh change and possible causes

Reduction in saltmarsh width

Change in the shape of the tidal curve reducing the period available for sediment accretion to occur

Increase in wave energy / increase in current speeds causing direct erosion through greater shear stress

Boat/ship wash causing direct erosion

Berth and channel deepening, leading to lowering of the intertidal area due to slumping (an increase in inshore water depth can also increase wave height in the intertidal zone)

Channel meandering in the estuary as a result of changes to tidal or fluvial flow

Change in the position of deep water channels or banks offshore, altering the pattern of waves and tidal currents

Creek lengthening and widening

Relative sea level rise (increasing the tidal prism)

Change in the shape of the tidal curve

Change in the floral community

Relative sea level rise leading to a change in inundation patterns

Grazing, potentially reducing diversity through alteration of conditions (including compaction and selective grazing)

Change in freshwater/seawater input

Loss of plant vigour

Increase in wave/tidal energy causing rotation of plants, loosening roots and general demise

Undesirable sediment chemistry (lack of nutrients, highly reduced environment etc.)

Pollution (as a result of spillage or from terrestrial runoff including herbicides and pesticides)

Disease (some species may be prone to diseases such as Wheat Rust)