Plant non-woody plants into moisture-retaining peat pots: freshwater wetlands

Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 1
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How is the evidence assessed?

Effectiveness

40%
Certainty

27%
Harms

0%

Calculating overall effectiveness category

Background information and definitions

Pots made from compressed peat can retain moisture during dry periods, which may improve survival or growth rates of planted marsh or swamp plants. Focal plants could be grown in peat pots in nurseries then planted with the pot in the field. Alternatively, peat pots could be inserted into the soil before planting. Caution: Extracting peat to produce peat pots could damage natural peatlands.

Study locations

Key messages

One study evaluated the effects of using moisture-retaining peat pots when planting emergent, non-woody vegetation in freshwater wetlands. The study was in the USA.

VEGETATION COMMUNITY

VEGETATION ABUNDANCE

Individual species abundance (1 study): One replicated, randomized, paired, controlled study in a wetland in the USA found that tussock sedge Carex stricta cover was similar across plots, after two growing seasons, whether sedges were planted into peat pots or into existing wetland soil.

VEGETATION STRUCTURE

Individual plant size (1 study): One replicated, randomized, paired, controlled study in a wetland in the USA found that the biomass of tussock sedge Carex stricta plants was similar, after two growing seasons, whether they were planted into peat pots or into existing wetland soil.

OTHER

Survival (1 study): One replicated, randomized, paired, controlled study in a wetland in the USA found that the survival rate of tussock sedge Carex stricta plants was similar, after two growing seasons, whether they were planted into peat pots or into existing wetland soil.
Growth (1 study): The same study found that the growth rate of tussock sedge Carex stricta was typically similar, over two growing seasons, when planted into peat pots or into existing wetland soil. However, in a dry area and in a dry year, planting in peat pots did increase the growth rate.

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

A replicated, randomized, paired, controlled study in 2012–2013 in a freshwater wetland in Wisconsin, USA (Doherty & Zedler 2015) found that planting tussock sedge Carex stricta into peat pots had no clear or significant effect on sedge survival, biomass or cover after two growing seasons, but did increase sedge growth rate in drier plots during the first growing season. After two growing seasons, sedges planted into peat pots or bare soil had similar survival rates (peat pots: 87–100%; bare soil: 100%; statistical significance not assessed). The above-ground biomass of surviving sedges was statistically similar under both treatments (peat pots: 6–34 g/plant; bare soil: 4–39 g/plant). The same was true for sedge cover (peat pots: 47–70%; bare soil: 38–62%). The growth rate of planted sedges was statistically similar in three of four comparisons (peat pots: 0.011–0.014 mm/mm/day; bare soil: 0.013–0.014 mm/mm/day). In the other comparison – in drier plots and in the first, drought-affected growing season – the growth rate was greater for sedges planted into peat pots (0.011 mm/mm/day) than sedges planted into bare soil (−0.003 mm/mm/day). Methods: In spring 2012, six pairs of 1-m² plots were established in a wetland undergoing restoration. Five nursery-reared tussock sedges were planted into each plot, then regularly watered and weeded. In half of the plots (one random plot/pair), the sedges were planted into peat pots sunk into the soil. Survival and above-ground biomass of planted sedges, and total tussock sedge cover, were surveyed in June–August 2013. Biomass was dried before weighing. Growth rates were calculated from leaf lengths measured in 2012 and 2013.
Study and other actions tested
Referenced paper
Doherty J.M. & Zedler J.B. (2015) Increasing substrate heterogeneity as a bet-hedging strategy for restoring wetland vegetation. Restoration Ecology, 23, 15-25.

Please cite as:

Taylor N.G., Grillas P., Smith R.K. & Sutherland W.J. (2021) Marsh and Swamp Conservation: Global Evidence for the Effects of Interventions to Conserve Marsh and Swamp Vegetation. Conservation Evidence Series Synopses. University of Cambridge, Cambridge, UK.

Where has this evidence come from?

List of journals searched by synopsis

All the journals searched for all synopses

This Action forms part of the Action Synopsis:

Marsh and Swamp Conservation

Related Actions

Actions	Effectiveness	Category
Plant trees/shrubs into moisture-retaining peat pots: brackish/saline wetlands Action Link	No evidence found (no assessment)	Synopsis Link
Treat tree/shrub seeds with chemicals before sowing: brackish/saline wetlands Action Link	No evidence found (no assessment)	Synopsis Link
Prune roots of non-woody plants before planting: freshwater wetlands Action Link	No evidence found (no assessment)	Synopsis Link