Study

Using sediment alginate amendment as a tool in the restoration of Spartina alterniflora marsh

  • Published source details Cain J.L. & Cohen R.A. (2014) Using sediment alginate amendment as a tool in the restoration of Spartina alterniflora marsh. Wetlands Ecology and Management, 22, 439-449

Actions

This study is summarised as evidence for the following.

Action Category

Add below-ground organic matter before/after planting non-woody plants: brackish/saline wetlands

Action Link
Marsh and Swamp Conservation

Directly plant non-woody plants: brackish/saline wetlands

Action Link
Marsh and Swamp Conservation
  1. Add below-ground organic matter before/after planting non-woody plants: brackish/saline wetlands

    A replicated, randomized, controlled, site comparison study in 2010–2012 in a salt marsh in Georgia, USA (Cain & Cohen 2014) found that adding alginate to the sediment before planting smooth cordgrass Spartina alterniflora had no significant effect on cordgrass density or height. The total number of live cordgrass stems increased by a statistically similar amount in plots with added alginate (from 35 stems/m2 at planting to 345 stems/m2 after 1–2 growing seasons) and plots without alginate (from 30 to 369 stems/m2). The same was true for the height of the tallest cordgrass plants (with alginate: from 48 to 58 cm; without alginate: from 45 to 56 cm). After three growing seasons, planted plots had a statistically similar live stem density to mature natural marshes (427 stems/m2) but taller plants than mature natural marshes (29 cm), whether alginate was added or not. The study noted a high sediment organic matter content (15%) before alginate addition. Methods: In May 2010, twenty 1-m2 plots were established on an intertidal mudflat where cordgrass had died off. All plots were planted with swards of cordgrass from nearby natural marsh, in nine holes 45 cm apart. In 10 random plots, 10 g of alginate (a carbon-rich seaweed extract) was poured into each hole before planting. Cordgrass stems were counted, and the five tallest stems/plot measured, in each plot over three growing seasons. A nearby natural marsh was also surveyed.

    (Summarised by: Nigel Taylor)

  2. Directly plant non-woody plants: brackish/saline wetlands

    A replicated, controlled, site comparison study in 2010–2012 in a salt marsh in Georgia, USA (Cain & Cohen 2014) found that the density and height of smooth cordgrass Spartina alterniflora increased in plots planted with cordgrass plants, and that after three growing seasons cordgrass density was similar in planted plots and natural marshes. The total number of live stems in plots planted with cordgrass increased from 30–35 stems/m2 at planting to 345–369 stems/m2 after three growing seasons. Maximum cordgrass height increased from 45–48 cm to 56–58 cm. Adding alginate did not significantly affect cordgrass density or height (see Action: Add below-ground organic matter before/after planting). After three growing seasons, planted plots contained taller cordgrass than mature natural marshes, but at a similar density (natural marshes: 29 cm tall; 427 stems/m2). Planted plots contained a greater density of cordgrass than unplanted plots, but of a similar height (unplanted plots: 89 stems/m2; 40 cm tall). Methods: In May 2010, thirty 1-m2 plots were established in an estuarine salt marsh. Twenty bare mud plots were planted with swards of cordgrass from nearby natural marsh, in nine holes 45 cm apart. Alginate (a carbon-rich seaweed extract) was added to half of these plots. Five bare mud plots were not planted. The final five plots were situated in patches of natural marsh. Cordgrass stems were counted, and the five tallest stems/plot measured, in each plot over three growing seasons.

    (Summarised by: Nigel Taylor)

Output references

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