Abandon aquaculture facilities: allow brackish/saline marshes or swamps to recover without active intervention

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

Source countries

Key messages

  • One study evaluated the effects, on vegetation, of abandoning aquaculture facilities with the expectation that brackish/saline marshes or swamps would recover spontaneously. The study was in Costa Rica.

VEGETATION COMMUNITY

  • Community composition (1 study): One site comparison study in Costa Rica reported that after 14 years, an abandoned shrimp pond contained the same four tree species as a nearby natural mangrove forest.

VEGETATION ABUNDANCE

  • Tree/shrub abundance (1 study): One site comparison study in Costa Rica reported that after 14 years, an abandoned shrimp pond contained a greater density of trees than a nearby natural mangrove forest.

VEGETATION STRUCTURE

  • Height (1 study): One site comparison study in Costa Rica reported that after 14 years, an abandoned shrimp pond had a shorter tree canopy than a nearby natural mangrove forest.
  • Basal area (1 study): The same study reported that the basal area of trees was smaller in an abandoned shrimp pond, after 14 years, than in a nearby natural mangrove forest.

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 site comparison study in 1996 of an abandoned aquaculture pond in Costa Rica (Stevenson et al. 1999) reported that it had developed into mangrove forest within 14 years – containing the same four tree species as nearby natural mangroves, but a greater density of smaller trees. Statistical significance was not assessed. On average, the abandoned pond contained 15,200 trees/ha with a basal area of 18 m2/ha. The average canopy height was 4–10 m/species. In comparison, a nearby remnant of natural mangrove forest contained 7,000 trees/ha with a basal area of 29 m2/ha. The average canopy height was 8–13 m/species. Methods: In 1996, vegetation was surveyed in an abandoned shrimp pond and a nearby natural mangrove forest (two 5 x 5 m plots/site). The 4-ha pond had been used for aquaculture for 20 years, but abandoned since 1982. Its outer dike naturally breached in 1987. Only trees >2 m tall were surveyed. The study country was identified for this summary using Lewis et al. (2002).

    Additional Reference

    Lewis R.R. III, Erftemeijer P.L.A., Sayaka A. & Kethkaew P. (2002) Mangrove rehabilitation after shrimp aquaculture: a case study in progress at the Don Sak National Forest Reserves, Surat Thani, Southern Thailand. Pages 108–128 in D.J. Macintosh, M.J. Phillips, R.R. Lewis III & B. Clough (eds.) Annexes to the Thematic Review on Coastal Wetland Habitats and Shrimp Aquaculture: Case Studies. World Bank, NACA, WWF and FAO Consortium Program on Shrimp Farming and the Environment.

    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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