Restoring assemblages of salt marsh halophytes in the presence of a rapidly colonizing dominant species

Published source details Armitage A.R., Boyer K.E., Vance R.R. & Ambrose R.F. (2006) Restoring assemblages of salt marsh halophytes in the presence of a rapidly colonizing dominant species. Wetlands, 26, 667-676.
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This study is summarised as evidence for the following.

	Action	Category
	Reprofile/relandscape: brackish/salt marshes Action Link
	Directly plant non-woody plants: brackish/saline wetlands Action Link

Reprofile/relandscape: brackish/salt marshes

A site comparison study in 1998–2002 of two salt marshes in California, USA (Armitage et al. 2006) reported that a reprofiled, planted and fenced marsh had lower vegetation cover than a nearby natural marsh after three growing seasons, but that both marshes were dominated by pickleweed Salicornia virginica. Statistical significance was not assessed. After three growing seasons, the created marsh had 62% total vegetation cover (compared to 87% in a nearby natural marsh). The most abundant species in both marshes was pickleweed (created: 39%; natural: 62% cover). Four plant species colonized plots where they had not been planted. In these plots, pickleweed cover was 23–27%. Where they colonized, the other species had <1% cover. Methods: In autumn 1997, an upland area was reprofiled to form an intertidal mudflat. In March 1998, rooted cuttings of four salt marsh herb/succulent species were planted into fifty-five 4-m² plots around the edge of the mudflat (25–81 plants/plot; combinations of 1 or 2 species/plot). After one growing season, the plots were protected with rabbit-proof fencing. Debris and colonizing vegetation were regularly removed during the first two growing seasons, but left in place thereafter. The study does not distinguish between the effects of reprofiling, planting and fencing on the non-planted vegetation. Total vegetation cover was measured in 0.25-m² quadrats: in the created marsh (1 quadrat/plot/year until October 2000) and a nearby natural marsh of similar elevation (10 quadrats in July 1999).

(Summarised by: Nigel Taylor)
Directly plant non-woody plants: brackish/saline wetlands

A replicated, site comparison study in 1998–2002 involving a reprofiled, planted and fenced salt marsh in California, USA (Armitage et al. 2006) reported 88–98% survival of planted salt marsh species after one growing season, but lower cover of vegetation overall and the dominant plant species compared to a natural marsh after three growing seasons. Statistical significance was not assessed. After one growing season, survival rates ranged from 88% for saltgrass Distichlis spicata to 98% for salt marsh daisy Jaumea carnosa. After three growing seasons, total vegetation cover in the created marsh was 62% (mostly pickleweed Salicornia virginica: 39% cover). In a nearby natural marsh total vegetation cover was 87% (mostly pickleweed: 62% cover). Each species had greater cover in plots where it was planted (pickleweed: 38–72%; other species: 10–57%) than where it colonized by itself (pickleweed: 23–27%; other species: <0.5%). For some species, the final cover and canopy height depended on planting density (see original paper). Methods: In autumn 1997, an upland area was reprofiled to form an intertidal mudflat. In March 1998, rooted cuttings of four salt marsh herb/succulent species were planted into fifty-five 4-m² plots around the edge of the mudflat (25–81 plants/plot; combinations of 1 or 2 species/plot). After one growing season, the plots were protected with rabbit-proof fencing. Debris and colonizing vegetation were regularly removed during the first two growing seasons, but left in place thereafter. The study does not distinguish between the effects of reprofiling, planting and fencing on the non-planted vegetation. Survival of planted individuals was monitored after one growing season. Total vegetation cover was measured in 0.25-m² quadrats: in the created marsh (1 quadrat/plot/year until October 2000) and a nearby natural marsh of similar elevation (10 quadrats in July 1999).

(Summarised by: Nigel Taylor)