Restore/create brackish/saline swamps in areas that will be climatically suitable in the future

How is the evidence assessed?
  • Effectiveness
  • Certainty
  • Harms

Study locations

Key messages

  • One study evaluated the effects, on vegetation, of restoring or creating brackish/saline swamps in areas expected to be climatically suitable in the future. The study was in South Africa.


  • Overall extent (1 study): One before-and-after study in an estuary in South Africa reported that over 42 years after planting mangrove trees just beyond their current range, the area of mangrove forests increased.




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 before-and-after study in 1969–2011 in an estuary in South Africa (Hoppe-Speer et al. 2015) reported that over 42 years after planting mangrove trees just outside their current range, the area of mangrove vegetation increased. Before planting, there were no mangroves present in the estuary. In the year after planting (1970), mangrove forests could not be identified on aerial photographs. Forty-two years after planting (2011), mangrove forests had established and covered 1.6 ha. Although mangroves encroached into and replaced existing salt marshes, the area of salt marsh in the estuary actually increased slightly over time (1970: 2.9 ha; 2011: 3.1 ha). Salt marshes developed on newly deposited sediment. Methods: In 1969, twenty-five grey mangrove Avicennia marina trees (age unclear) were planted into salt marsh in the Nahoon Estuary. This site is 60 km south of naturally occurring mangrove forests in South Africa. “A few” mangrove trees of other species were planted “a few” years later. The area of mangrove forest and salt marsh in the estuary was determined from aerial photographs (taken 1970–2004), satellite images (taken 2004–2010) and field surveys (2011).

    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

All the journals searched for all synopses

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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