Assisted revegetation trials in degraded salt-marshes

Published source details Handa I.T. & Jeffries R.L. (2000) Assisted revegetation trials in degraded salt-marshes. Journal of Applied Ecology, 37, 944-958.
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This study is summarised as evidence for the following.

	Action	Category
	Add surface mulch before/after planting non-woody plants: brackish/saline wetlands Action Link
	Add inorganic fertilizer before/after planting non-woody plants: brackish/saline wetlands Action Link
	Directly plant non-woody plants: brackish/saline wetlands Action Link

Add surface mulch before/after planting non-woody plants: brackish/saline wetlands

A replicated, randomized, paired, controlled study in 1996–1997 in two degraded, intertidal, brackish marshes in Manitoba, Canada (Handa & Jeffries 2000) found that adding surface mulch increased the cover of one of two planted herb species, but did not significantly affect survival rates of either species or overall above-ground biomass. On all five survey dates across the second growing season after planting, creeping alkaligrass Puccinellia phryganodes cover was higher in mulched plots (1,820–5,400 mm²/m²) than unmulched plots (1,090–3,810 mm²/m²). However, cover of estuary sedge Carex subspathacea never significantly differed between treatments (mulched: 670–2,880 mm²/m²; unmulched: 720–2,600 mm²/m²). On all five dates, survival rates were statistically similar under each treatment for both alkaligrass (mulched: 87–100%; unmulched: 52–93%) and estuary sedge (mulched: 28–58%; unmulched: 23–50%). On at least two of three dates (results not clearly reported), live above-ground biomass was statistically similar under each treatment for both alkaligrass-dominated vegetation (mulched: 45–178 g/m²; unmulched: 29–122 g/m²) and sedge-dominated vegetation (mulched: 1–4 g/m²; unmulched: 1–4 g/m²). Methods: In June 1996, plugs of creeping alkaligrass and estuary sedge were transplanted from natural stands to 1-m² plots within brackish marsh vegetation damaged by geese (one species/marsh; 12 plots/species; 42 plugs/plot). Two random quarters of each plot were mulched after planting (5 mm layer of peat from a nearby marsh). Half of each plot was also fertilized. All plots were fenced to exclude geese. Vegetation was surveyed in summer 1997. Survival and cover were monitored for planted plants in the centre of each plot. Vegetation samples were cut from the margins of each plot, then washed to remove dead biomass, dried and weighed.

(Summarised by: Nigel Taylor)
Add inorganic fertilizer before/after planting non-woody plants: brackish/saline wetlands

A replicated, randomized, paired, controlled study in 1996–1997 in two degraded, intertidal, brackish marshes in Manitoba, Canada (Handa & Jeffries 2000) found that adding fertilizer increased the cover of one of two planted herb species, but did not significantly affect survival rates of either species or overall above-ground biomass. On all five survey dates across the second growing season after planting, creeping alkaligrass Puccinellia phryganodes cover was higher in fertilized plots (1,720–5,400 mm²/m²) than in unfertilized plots (1,020–4,870 mm²/m²). However, cover of estuary sedge Carex subspathacea never significantly differed between treatments (fertilized: 670–2,880 mm²/m²; unfertilized: 670–2,720 mm²/m²). On all five dates, survival rates were statistically similar under each treatment, for both alkaligrass (fertilized: 52–100%; unfertilized: 47–100%) and estuary sedge (fertilized: 24–58%; unfertilized: 23–50%). On at least two of three dates (results not clearly reported), live above-ground biomass was statistically similar under each treatment for both alkaligrass-dominated vegetation (fertilized: 47–178 g/m²; unfertilized: 29–99 g/m²) and sedge-dominated vegetation (fertilized: 1–4 g/m²; unfertilized: 1–4 g/m²). Methods: In June 1996, plugs of creeping alkaligrass and estuary sedge were transplanted from natural stands to 1-m² plots within brackish marsh vegetation damaged by geese (one species/marsh; 12 plots/species; 42 plugs/plot). Two random quarters of each plot were fertilized with N and P at planting (10.5 g N/m² and 4.5 g P/m²). Half of each plot was also mulched. All plots were fenced to exclude geese. Vegetation was surveyed in summer 1997. Survival and cover were monitored for planted plants in the centre of each plot. Vegetation samples were cut from the margins of each plot, then washed to remove dead biomass, dried and weighed.

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

A replicated study in 1996–1997 in two degraded, coastal, brackish marshes in Manitoba, Canada (Handa & Jeffries 2000) reported 24–100% survival of two transplanted herb species after two growing seasons, and that their cover had increased. Statistical significance was not assessed. Two growing seasons after planting, creeping alkaligrass Puccinellia phryganodes had a survival rate of 47–100% and black estuary sedge Carex subspathacea had a survival rate of 24–50%. Cover of surviving alkaligrass was 1,600–5,400 mm²/m² (vs 200 mm²/m² when planted). Cover of surviving estuary sedge was 700–2,800 mm²/m² (vs 200 mm²/m² when planted). Adding mulch or fertilizer significantly increased the cover of alkaligrass but not estuary sedge, and did not significantly affect survival rates (see Actions: Add surface mulch before/after planting and Add inorganic fertilizer before/after planting). Methods: In June 1996, plugs of alkaligrass and estuary sedge were transplanted from natural stands to 1-m² plots within brackish marsh vegetation damaged by geese (one species/marsh; 12 plots/species; 42 plugs/plot). All plots were fenced to exclude geese. Mulch (5 mm peat layer) and/or fertilizer (N and P) were added to three quarters of each planted plot. Survival and cover (basal area) of planted vegetation in the centre of each plot were monitored until mid-August 1997.

(Summarised by: Nigel Taylor)