Northey Island, managed retreat scheme: Results of botanical monitoring 1991–1994

  • Published source details Dagley J.R. (1995) Northey Island, managed retreat scheme: Results of botanical monitoring 1991–1994. Natural England (English Nature) report, English Nature Research Report 128.


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 before-and-after study in 1991–1994 of a coastal site where tidal exchange was restored in England, UK (Dagley 1995) reported that salt marsh vegetation colonized the site within one year, and that salt marsh plant communities developed within three years. Before intervention, the site was a coastal grassland containing 14 plant species. One year after intervention, the site contained 17 plant and algae species (1.6 species/m2) – mostly the alga Enteromorpha sp. (present in 88% of quadrats). After 2–3 years, the site contained 22–25 plant and algae species (3.0–3.5 species/m2). It had developed a recognizable salt marsh vegetation community. The most common species were glassworts Salicornia spp. (in 88–94% of quadrats) and seablite Suaeda maritima (in 64–74% of quadrats), along with Enteromorpha sp. (in 88–96% of quadrats). Methods: In July 1991, a sea wall was lowered to allow tidal exchange on 2 acres of Northey Island. The studied area was inundated by 100 tides/year. Vegetation was surveyed (50 randomly placed quadrats/year; ≤1 m2) before intervention (June 1991) and for three years after (summer 1992–1994). The restoration site was included in studies (7) and (11).

    (Summarised by: Nigel Taylor)

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