Add cover other than mulch before/after planting trees/shrubs: freshwater wetlands
Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 1
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.
Supporting evidence from individual studies
A replicated, randomized, paired, controlled study in 2014–2015 in two degraded floodplain swamps in Victoria, Australia (Greet et al. 2016) found that covering plots with plastic or jute matting before planting native shrubs and tree seedlings had no significant effect on their cover or height. One year after planting, plots with and without mats had statistically similar cover of native shrubs (mats: 7–14%; no mats: 4–8%) and swamp gum Eucalyptus camphora (mats: 11–22%; no mats: 7–11%). Swamp gum saplings were a statistically similar height in plots with and without mats (data not reported). Additionally, plots with mats 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 shrubs (1 plant/m2; species not reported), swamp gum seedlings (1 plant/2 m2) and understory herbs (3 plants/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