Effects of phenological stage of Spartina alterniflora transplant culms on stand development

Published source details Tanner G.W. & Dodd J.D. (1984) Effects of phenological stage of Spartina alterniflora transplant culms on stand development. Wetlands, 4, 57-74.
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This study is summarised as evidence for the following.

	Action	Category
	Apply root dip to non-woody plants before planting: 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

Apply root dip to non-woody plants before planting: brackish/saline wetlands

A replicated, randomized, paired, controlled study in 1976–1977 on two intertidal mudflats in Texas, USA (Tanner & Dodd 1985) found that applying root dip to smooth cordgrass Spartina alterniflora before planting typically reduced survival after one growing season, but had mixed effects on cordgrass density and height after 1–2 growing seasons. After one growing season, dipped cordgrass had a lower survival rate than undipped cordgrass in five of six comparisons (for which dipped: 3–19%; undipped: 39–85%; other comparison no significant difference). After 1–2 growing seasons, cordgrass density was statistically similar under both treatments in 7 of 12 comparisons (for which dipped: <1–191 shoots/m²; undipped: <1–168 stems/m²) but was lower in plots planted with dipped cordgrass in the other five comparisons (dipped: 1–38 stems/m²; undipped: 21–252 stems/m²). Finally, after two growing seasons, cordgrass shoots were of statistically similar height under both treatments in three of six comparisons (for which dipped: 117–120 cm; undipped: 112–122 cm) but taller in plots planted with dipped cordgrass in two comparisons (dipped: 132–139 cm; undipped: 110–119 cm) and shorter in plots planted with dipped cordgrass in the final comparison (dipped: 84 cm; undipped: 122 cm). Methods: In July 1976, thirty-six 12.5-m² plots were established across two intertidal mudflats. Smooth cordgrass (20–100 cm tall) was transplanted into each plot (50 plants/plot, 50 cm apart. For half of the plots (9 random plots/mudflat), cordgrass was dipped into commercial root dip (Algenura-a; designed to increase water uptake) for 15 min immediately before planting. Cordgrass survival and density were recorded in October 1976. Cordgrass density and flowering shoot height were sampled in November 1977.

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

A replicated, randomized, paired, controlled study in 1976–1977 on two intertidal mudflats in Texas, USA (Tanner & Dodd 1985) found that applying fertilizer after planting smooth cordgrass Spartina alterniflora typically had no significant effect on its survival, height, density or biomass. After one growing season, cordgrass survival was statistically similar in fertilized and unfertilized plots in 12 of 12 comparisons (fertilized: 18–89%; unfertilized: 9–85%). After two growing seasons, cordgrass height was statistically similar under both treatments in 11 of 12 comparisons (for which fertilized: 117–127 cm; unfertilized: 110–122 cm; other comparison shorter in fertilized than unfertilized plots). After 1–2 growing seasons, cordgrass density was statistically similar under both treatments in 20 of 24 comparisons (for which fertilized: 2–252 stems/m²; unfertilized: <1–252 stems/m²; other comparisons a mix of higher and lower density in fertilized than unfertilized plots). Above-ground cordgrass biomass was statistically similar under both treatments in 24 of 24 comparisons (fertilized: 23–1,840 g/m²; unfertilized: 20–1,700 g/m²). The same was true for live and dead biomass separately (12 of 12 comparisons; see original paper for data). Methods: In July 1976, fifty-four 12.5-m² plots were established across two intertidal mudflats. Smooth cordgrass (20–100 cm tall) was transplanted into each plot (50 plants/plot, 50 cm apart. Thirty-six of the plots (18 random plots/mudflat) were fertilized after planting (NPK; 12 or 24 g/m²). The other plots were not fertilized. Cordgrass was monitored in October–November 1976 and 1977. Monitoring included counting stems, measuring representative flowering stems, and cutting, drying and weighing three cordgrass plants/plot. This study used the same marsh as (3), but a different experimental set-up.

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

A replicated study in 1976–1977 on two intertidal mudflats in Texas, USA (Tanner & Dodd 1985) reported 3–89% survival of planted smooth cordgrass Spartina alterniflora after one growing season, and increases in stem height, density and biomass over two growing seasons. Unless specified, statistical significance was not assessed. After two growing seasons, cordgrass stems were 84–140 cm tall (vs 20–100 cm when planted). There were 18–252 cordgrass stems/m² (vs <1–35 stems/m² after one growing season and 4 stems/m² when planted). Above-ground cordgrass biomass was 466–1,840 g/m² (vs 20–104 g/m² after one growing season). Amongst planted plots, results depended on the mudflat and the age/form of the cordgrass (see original paper) and whether plants were treated with root dip before planting (see Action: Apply root dip to plants before planting). Fertilizer typically had no significant effect on the results (see Action: Add inorganic fertilizer before/after planting). Methods: In July 1976, smooth cordgrass was transplanted into seventy-two 12.5-m² plots (50 plants/plot, 50 cm apart) across two intertidal mudflats. Transplants were dug from existing salt marshes (young, mature short-form or mature tall-form). Some plants were treated with root dip before planting, and some plots were fertilized after planting. Cordgrass was monitored over the growing season in 1976 and 1977. Monitoring included counting stems, measuring representative flowering stems, and cutting, drying and weighing three cordgrass plants/plot.

(Summarised by: Nigel Taylor)