A regional assessment of salt marsh restoration and monitoring the Gulf of Maine

Published source details Konisky R.A., Burdick D.M., Dionne M. & Neckles H.A. (2006) A regional assessment of salt marsh restoration and monitoring the Gulf of Maine. Restoration Ecology, 14, 516-525.
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This study is summarised as evidence for the following.

	Action	Category
	Facilitate tidal exchange to restore degraded brackish/salt marshes Action Link

Facilitate tidal exchange to restore degraded brackish/salt marshes

A replicated, before-and-after, site comparison study including up to 36 salt marsh restoration projects in the Gulf of Maine, North America (Konisky et al. 2006) found that after improving tidal exchange, cover of salt-loving species did not increase, cover of fresh/brackish species decreased, and plant species richness remained stable. Before intervention, tidally restricted marshes had lower cover of salt-loving species than natural marshes (degraded: 48%; natural: 64%) and greater cover of fresh/brackish species (degraded: 10%; natural: 3%) but contained a statistically similar number of plant species (degraded: 6.9; natural: 6.6 species/marsh). After three or more years, tidally restored marshes still had lower cover of salt-loving species (47%) than natural marshes, but now had statistically similar cover of fresh/brackish species (6%) and retained statistically similar plant species richness (6.6 species/marsh). There was a temporary dip in cover of salt-loving species (33% after two years). The pattern of results was similar for each of three restoration methods considered (see original paper for data). Methods: The study collated data on vegetation cover and species richness from up to 36 coastal salt marsh restoration projects (7–25 marshes with data for each metric in a given year). The projects were completed, ongoing or pending between 1995 and 2003. They involved restoring tidal hydrology to tidally restricted marshes by (a) removing culverts or tide gates, (b) plugging drainage ditches, or (c) excavating tidal channels or raised areas. Data were averaged (a) for the last year before intervention, (b) for 1, 2 and ≥3 years after intervention, and (c) for natural reference marshes.

(Summarised by: Nigel Taylor)