Use herbicide to control problematic plants: brackish/saline swamps

Overall effectiveness category No evidence found (no assessment)
Number of studies: 0
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Effectiveness

not assessed
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not assessed
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not assessed

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Background information and definitions

Herbicides can be applied to an entire area of vegetation, or targeted at individual problematic species (e.g. by painting onto individual plants, or shielding non-target vegetation). Herbicides could be applied once, or repeatedly to kill established vegetation or recurrent growth from the seed bank. To maximize contact with target species and minimize non-target effects, herbicides might be applied during/at the start of the dry season, as the tide is going out, or on calm rather than windy days (e.g. Tobias et al. 2016). Often, herbicide application will follow or be followed by other interventions, such as mowing, burning or physical removal of problematic plants.

Caution: In many herbicides, the active chemicals are not specific to the problematic species so can cause collateral damage to desirable species. Relying on herbicides as the only tool to manage problematic plants can lead to the development of herbicide resistance in future generations (Powles et al. 1997). Herbicides can have severe negative side effects on biodiversity, the environment and human health (Pimentel et al. 1992). Accordingly, herbicide use – particularly in or near wetlands or water bodies – is limited in many countries.

Bear in mind that the effects of herbicide might be highly dependent on the chemical used, how it is applied (e.g. season and number of applications), and local site conditions (e.g. nutrient availability, water levels, proximity of untreated invaded vegetation) (Tobias et al. 2016). Also, similarity between treated and untreated, degraded areas might not be an undesirable outcome for this action: similarity in vegetation cover after months or years could suggest, for example, that native vegetation abundance has recovered after being initially depressed by herbicide.

For this action, “vegetation” refers to overall or non-target vegetation. Studies that only report responses of target problematic plants have not been summarized.

Related actions: Use herbicide to maintain or restore disturbance; Introduce organisms to control problematic plants, including introduction of microorganisms as “bioherbicides”.

^{Pimentel D., Acquay H., Biltonen M., Rice P., Silva M., Nelson J., Lipner V., Giordano S., Horowitz A. & D’Amore M. (1992) Environmental and economic costs of pesticide use. BioScience, 42, 750–760.}

^{Powles S.B., Preston C., Bryan I.B. & Jutsum A.R. (1997) Herbicide resistance: impact and management. Advances in Agronomy, 58, 57–93.}

^{Tobias V.D., Block G. & Laca E.A. (2016) Controlling perennial pepperweed (Lepidium latifolium) in a brackish tidal marsh. Wetlands Ecology and Management, 24, 411–418.}

Key messages

We found no studies that evaluated the effects, on vegetation, of using herbicide to control problematic plants in brackish/saline swamps.

‘We found no studies’ means that we have not yet found any studies that have directly evaluated this action during our systematic journal and report searches. Therefore we have been unable to assess whether or not the action is effective or has any harmful impacts. Please get in touch if you know of such a study for this action.

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.

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
Manage water level to control problematic plants Action Link	No evidence found (no assessment)	0	Synopsis Link
Introduce organisms to control problematic plants: freshwater swamps Action Link	Unknown effectiveness (limited evidence)	1	Synopsis Link
Add salt to control problematic plants: brackish/saline swamps Action Link	No evidence found (no assessment)	0	Synopsis Link