Evaluation of created freshwater wetlands in Massachusetts

Published source details Jarman N.M., Dobberteen R.A., Windmiller B. & Lelito P.R. (1991) Evaluation of created freshwater wetlands in Massachusetts. Restoration & Management Notes, 9, 26-29.
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This study is summarised as evidence for the following.

	Action	Category
	Prune roots of trees/shrubs before planting: freshwater wetlands Action Link
	Restore/create freshwater marshes or swamps (multiple actions) Action Link
	Directly plant trees/shrubs: freshwater wetlands Action Link

Prune roots of trees/shrubs before planting: freshwater wetlands

A replicated, controlled study in 1988–1990 in up to five created freshwater wetlands in eastern Massachusetts, USA (Jarman et al. 1991) reported that pruning the roots of red maple Acer rubrum saplings before planting increased their survival rate. Statistical significance was not assessed. After approximately 1–2 years, saplings with roots pruned “several months” before planting had a >75% survival rate, compared to <25% for unpruned saplings. Methods: In the late 1980s, red maple saplings saved from destroyed wetlands were planted in up to five newly created wetlands (excavated from uplands, connected to natural wetlands, planted with herbs and shrubs as well as red maple). The roots of some saplings were pruned before planting. The study does not report the number of saplings planted, the precise number of wetlands planted with red maple, or precise dates of planting and monitoring.

(Summarised by: Nigel Taylor)
Restore/create freshwater marshes or swamps (multiple actions)

A replicated, paired, site comparison study in 1988–1990 involving six created freshwater wetlands in eastern Massachusetts, USA (Jarman et al. 1991) reported that they all developed vegetation cover within 1–2 years, with a similar plant species richness to adjacent natural wetlands but a distinct species composition. Statistical significance was not assessed. Created wetlands contained 9–20 plant species (vs natural: 13–23). The created and natural wetlands had 35–79% of plant species in common (average: 52%). All six created wetlands had >75% cover of native wetland vegetation. Woody plant cover was only 5–30%, suggesting herbaceous species were dominant (data not reported). Most adjacent natural wetlands, representing the target state, had a tree canopy with shrub and herb understory layers (not quantified). Red maple Acer rubrum seedlings were found in three of six created wetlands, at a density of 3–18/m². Methods: In late 1990, vegetation was surveyed in six created wetlands (88–800 m²) and an unspecified number of adjacent natural wetlands. Surveys covered all woody vegetation and herbaceous vegetation in five 1-m² quadrats/wetland. Wetland creation, in summer 1988 or 1989, involved excavating, creating “hydrological connections” to adjacent wetlands, adding wetland soil, planting wetland shrubs (six sites), herbs (five sites) or sods of vegetation (three sites), and sowing seeds of wetland herbs (one site).

(Summarised by: Nigel Taylor)
Directly plant trees/shrubs: freshwater wetlands

A replicated study in 1988–1990 in up to five created freshwater wetlands in eastern Massachusetts, USA (Jarman et al. 1991) reported that survival of planted red maple Acer rubrum saplings depended on whether their roots were pruned. Statistical significance was not assessed. After approximately 1–2 years, the survival rate was >75% for saplings whose roots had been pruned “several months” before planting, but <25% for saplings whose roots had not been pruned. Methods: In the late 1980s, red maple saplings saved from destroyed wetlands were planted in up to five newly created wetlands (excavated from uplands, connected to natural wetlands, planted with herbs and shrubs as well as red maple). The roots of some saplings were pruned before planting. The study does not report the number of saplings planted, the precise number of wetlands planted with red maple, or precise dates of planting and monitoring.

(Summarised by: Nigel Taylor)