Study

Does managed coastal realignment create saltmarshes with ‘equivalent biological characteristics’ to natural reference sites?

  • Published source details Mossman H.L., Davy A.J. & Grant A. (2012) Does managed coastal realignment create saltmarshes with ‘equivalent biological characteristics’ to natural reference sites?. Journal of Applied Ecology, 49, 1446-1456.

Actions

This study is summarised as evidence for the following.

Action Category

Facilitate tidal exchange to restore/create brackish/salt marshes from other land uses

Action Link
Marsh and Swamp Conservation
  1. Facilitate tidal exchange to restore/create brackish/salt marshes from other land uses

    A replicated, site comparison study in 2004–2010 of 52 salt marshes in England, UK (Mossman et al. 2012) reported that restored marshes (deliberately exposed to tidal influx) were colonized by salt-tolerant plants within one year, but found that they had a different plant community with lower diversity and cover than natural salt marshes. After 1–14 years, restored marshes contained 21–80% of all salt-tolerant plant species recorded in the study (vs 27–77% in natural marshes; statistical significance not assessed). However, the overall composition of the plant community significantly differed between restored and natural marshes (data reported as a graphical analysis). Plant diversity was also lower in quadrats from restored marshes (data reported as a diversity index). In three of three comparisons, restored marshes had lower overall vegetation cover (53–83%) than natural marshes (84–98%). Restored marshes had significantly lower cover of Atriplex portulacoides in three of three comparisons (restored: 7–9%; natural: 17–21%) and significantly greater cover of glasswort Salicornia europaea in two of three comparisons (for which restored: 12–21%; natural: 5–12%), but similar cover of saltmarsh grass Puccinellia maritima in two of three comparisons (for which restored: 23–32%; natural: 29–31%; see original paper for full cover data). Methods: In summer–autumn 2004–2010, vegetation was surveyed in 52 salt marshes: 18 marshes restored from agricultural land 1–14 years previously by deliberately breaching sea walls, and 34 nearby natural marshes. Cover of all vascular plant species, and bare ground, were estimated in at least fifty 0.25-m2 quadrats/marsh (along transects perpendicular to shoreline). Species within 20 m of transects were also noted. This study included the sites studied in (1), (7) and (8).

    (Summarised by: Nigel Taylor)

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