Use prescribed fire to control problematic plants: freshwater swamps

How is the evidence assessed?
  • Effectiveness
    not assessed
  • Certainty
    not assessed
  • Harms
    not assessed

Study locations

Key messages

  • One study evaluated the effects, on vegetation, of using prescribed fire to control problematic plants in freshwater swamps. The study was in the USA.

VEGETATION COMMUNITY

  • Overall richness/diversity (1 study): One replicated, randomized, controlled study aiming to restore a swamp in the USA found that burning canarygrass-invaded vegetation after spraying it with herbicide increased overall plant diversity, two growing seasons later, compared to spraying alone. However, burning had no significant effect on plant species richness.
  • Native/non-target richness/diversity (1 study): The same study found that burning canarygrass-invaded vegetation after spraying it with herbicide had no significant effect on native plant species richness, two growing seasons later, compared to spraying alone.

VEGETATION ABUNDANCE

  • Tree/shrub abundance (1 study): One replicated, randomized, controlled study aiming to restore a swamp in the USA found that burning canarygrass-invaded vegetation after spraying it with herbicide had no significant effect on the density of non-planted tree seedlings, two growing seasons later, compared to spraying alone.
  • Individual species abundance (1 study): The same study reported that burning canarygrass-invaded vegetation after spraying it with herbicide affected the abundance of some individual plant species two growing seasons 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

  1. A replicated, randomized, controlled study in 2002–2004 aiming to restore a swamp in a reed canarygrass Phalaris arundinacea stand in Wisconsin, USA (Hovick & Reinartz 2007) found that burning after spraying herbicide increased plant diversity more than spraying alone, but that burning had no additional effect on plant richness or the number of tree seedlings. After two growing seasons, the vegetation was more diverse in burned/sprayed plots than in plots that had only been sprayed (data reported as a diversity index). The treatments did not significantly differ in overall plant richness (burned/sprayed: 9.3; sprayed: 6.6 species/m2), native plant richness (burned/sprayed: 6.3; sprayed: 4.0 species/m2) or density of non-planted tree seedlings (burned/sprayed: 21; sprayed: 25 seedlings/m2). The study also reported differences between treatments in the abundance of individual plant species(statistical significance not assessed). For example, eastern willow herb Epilobium coloratum was more abundant in burned/sprayed plots (70% of quadrats; 10% cover) than sprayed plots (40% of quadrats; 6% cover). Reed canarygrass was less abundant in burned/sprayed plots (80% of quadrats; 34% cover) than sprayed plots (100% of quadrats; 73% cover). Methods: Twelve plots were established in a canarygrass-invaded wetland. All 12 plots were sprayed with herbicide (Roundup®) in November 2002, and planted with tree/shrub seedlings (roughly 1 seedling/m2) in spring 2003. Four random plots were also burned, before planting, in spring 2003. In August 2004, plant species and their cover were surveyed in ten 1-m2 quadrats/treatment, ignoring planted trees/shrubs.

    Study and other actions tested
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?

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Marsh and Swamp Conservation

This Action forms part of the Action Synopsis:

Marsh and Swamp Conservation
Marsh and Swamp Conservation

Marsh and Swamp Conservation - Published 2021

Marsh and Swamp Synopsis

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