Control problematic plants (multiple interventions): freshwater marshes or swamps

How is the evidence assessed?
  • Effectiveness
    45%
  • Certainty
    30%
  • Harms
    0%

Study locations

Key messages

  • One study evaluated the effects, on vegetation, of controlling problematic plants in freshwater marshes or swamps using >3 combined interventions. The study was in Costa Rica.

VEGETATION COMMUNITY

  • Overall extent (1 study): One controlled study in a freshwater marsh in Costa Rica reported that coverage of live vegetation stands was lower in a plot where southern cattail Typha domingensis had been controlled for >15 years than in a plot where cattail had not been controlled.
  • Overall richness/diversity (1 study): The same study reported that a plot in which southern cattail Typha domingensis had been controlled for >15 years had greater plant species richness than a plot where cattail had not been controlled.

VEGETATION ABUNDANCE

  • Overall abundance (1 study): One controlled study in a freshwater marsh in Costa Rica reported that a plot in which southern cattail Typha domingensis had been controlled for >15 years had less live vegetation cover than a plot where cattail had not been controlled.

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 controlled study in 1987–2004 in an ephemeral freshwater marsh in Costa Rica (Trama et al. 2009) reported that controlling invasive southern cattail Typha domingensis with multiple interventions reduced the total vegetated area and vegetation cover, but increased plant species richness. Unless specified, statistical significance was not assessed. After approximately 15–17 years, a managed plot (where cattail had been controlled) contained less live vegetation overall than an unmanaged plot. This was true for the total area of live vegetation (managed: 28–85%; unmanaged: 98–100%) and cover of live vegetation along transects (managed: 35–91%; unmanaged: 88–100%). Abundance varied across seasons. The managed plot also contained less cattail – both in terms of the total area (managed: 9–24% of plot; unmanaged: 63–66% of plot) and cover along transects (managed: 5–10%; unmanaged: 75–100%). Finally, the managed plot contained more plant species in total (managed: 59; unmanaged: 20) and had significantly greater plant species richness (managed: 13; unmanaged: 4 species/300 m2 transect). Methods: Two 80-ha plots were established in a cattail-dominated marsh. Cattail stands were managed in one of the plots: with multiple experimental interventions from 1987 (including cutting by hand, mowing, physical damage, grazing and burning, alone and in combination) then by physical damage alone from September 2002 (driving over it in a tractor with large paddle wheels). Water supply was also restored to both plots in July 2002. Vegetation stands were mapped from aerial photographs or satellite images taken in November 2002 (wet season) and March 2003 (dry season). Detailed vegetation surveys, along six 25 x 2 m transects/plot, were carried out between August 2003 and July 2004.

    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?

List of journals searched by synopsis

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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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