Add cover other than mulch before/after planting non-woody plants: freshwater wetlands

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

Effectiveness

60%
Certainty

32%
Harms

3%

Calculating overall effectiveness category

Background information and definitions

Planted vegetation may be damaged by hot, dry and bright conditions on bare wetland surfaces. Covers such as plastic mesh, sheets, or shelters for individual plants could ameliorate these factors and help planted vegetation to establish. The precise effect of covers may vary depending on the material used and how it is applied (e.g. to a large area vs individual plants; on the wetland surface vs suspended above the surface).

Related actions: Add cover other than mulch, other than to complement planting; Add surface mulch to complement planting; Use fences or barriers to protect planted areas from physical damage, e.g. with tree guards or breakwaters.

Study locations

Key messages

One study evaluated the effects, on vegetation, of adding cover other than mulch to freshwater wetlands planted with emergent, non-woody plants. The study was in Australia.

VEGETATION COMMUNITY

VEGETATION ABUNDANCE

Tree/shrub abundance (1 study): One replicated, randomized, paired, controlled study in floodplain swamps in Australia found that covering plots with plastic or jute mats before planting native understory herbs increased their overall cover, one year later.
Individual species abundance (1 study): The same study found that covering plots with plastic or jute mats before planting native understory herbs reduced the cover of two problematic herb species, one year later.

VEGETATION STRUCTURE

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 2014–2015 in a degraded floodplain swamp in Victoria, Australia (Greet et al. 2016) found that covering plots with plastic or jute matting before planting native understory herbs increased their cover. One year after planting, plots with mats had higher cover of native understory herbs (18–33%) than plots without mats (2–4%). Plots with mats also had lower cover of problematic reed canarygrass Phalaris arundinacea and common reed Phragmites australis (4–28%) than plots without mats (73–99%). Methods: In February–March 2014, six 100-m² plots were established in each of two floodplain wetlands. All plots had been recently cut and sprayed with herbicide (to control reed canarygrass or common reed) and fenced to exclude large animals. Four plots (two random plots/site) received each cover treatment: plastic weed matting, jute matting, or no matting. All plots were then planted with native understory herbs (3 plants/m²; species not reported), plus shrubs (1 plant/m²) and tree seedlings (1 plant/2 m²). Holes were cut in the matting to allow planting. Vegetation was surveyed in March 2015, in five 1-m² quadrats/plot.
Study and other actions tested
Referenced paper
Greet J., King E. & Stewart-Howie M. (2016) Plastic weed matting is better than jute or woodchips for controlling the invasive wetland grass species Phalaris arundinacea, but not Phragmites australis. Plant Protection Quarterly, 31, 19-22.

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	Studies	Category
Transplant wetland soil before/after planting trees/shrubs: freshwater wetlands Action Link	No evidence found (no assessment)	0	Synopsis Link
Add below-ground organic matter before/after planting non-woody plants: brackish/saline wetlands Action Link	Likely to be beneficial	6	Synopsis Link
Use fences or barriers to protect freshwater wetlands planted with non-woody plants Action Link	Likely to be beneficial	4	Synopsis Link