Some influences of sediment addition to a deteriorating salt marsh in the Mississippi River deltaic plain: a pilot study

  • Published source details DeLaune R.D., Pezeshki S.R., Pardue J.H., Whitcomb J.H. & Patrick W.H. Jr. (1990) Some influences of sediment addition to a deteriorating salt marsh in the Mississippi River deltaic plain: a pilot study. Journal of Coastal Research, 6, 181-188.


This study is summarised as evidence for the following.

Action Category

Add sediment: brackish/salt marshes

Action Link
Marsh and Swamp Conservation
  1. Add sediment: brackish/salt marshes

    A replicated, randomized, paired, controlled study in 1986–1987 in a subsiding tidal salt marsh in Louisiana, USA (DeLaune et al. 1990) found that adding sediment increased smooth cordgrass Spartina alterniflora density and biomass, but not its height. Sixteen months after the first amendment, plots amended with sediment contained more smooth cordgrass stems (high dose: 75 stems/0.25 m2; low dose: 65 stems/0.25 m2) than unamended plots (47 stems/0.25 m2). Above-ground biomass of smooth cordgrass was greater in amended than unamended plots, although only significantly so for the high sediment dose. This was true for both overall biomass (high dose: 527; low dose: 406; unamended; 288 g/0.25 m2) and for live biomass only (high dose: 368; low dose: 268; unamended; 184 g/0.25 m2). Smooth cordgrass height did not significantly differ between treatments (high dose: 41; low dose: 41; unamended: 43 cm). Methods: In July 1986, twelve 1.44-m2 plots were established (in four sets of three) on a degraded, cordgrass-dominated salt marsh. Eight plots (two random plots/set) were amended with dredged river alluvium: either high dose (94 kg/m2) or low dose (47 kg/m2). Half of the sediment was added in July 1986 and half in June 1987. The other four plots received no sediment. In November 1987, vegetation was cut from one 0.25-m2 quadrat/plot. Five random stems were measured, then all sampled vegetation was dried and weighed. This study was based on the same experimental set-up as (2).

    (Summarised by: Nigel Taylor)

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