Three More Reasons Why Mangroves Should Be an Integral Part of Coastal Development Strategy

Mangrove wetland in Antigua. Mangrove root systems provide valuable habitat and ecosystem services to surrounding areas.

​It’s no secret that scientists and conservationists are alarmed by the loss of mangroves around the world, as these ecosystems provide valuable storm protection and water filtration to tropical coastal areas. A recent study reveals that there’s additional value to incorporating mangrove habitats into coastal development and management. Described below are three more reasons mangrove restoration should be incorporated into coastal development strategy:
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1. Mangroves remove CO2 from the atmosphere, mitigating greenhouse gas emissions and outperforming most other terrestrial forests. Mangroves outperform most other forests in their capacity to store carbon, holding up to four times more carbon than tropical rainforests. They remove carbon dioxide from the atmosphere and store it as plant material. When mangrove roots, branches and leaves die they are covered by soil, and then submerged below tidal water. This saline, anoxic environment slows the breakdown of organic materials and boosts carbon storage. Rising sea levels create more upper-surface land that is available for carbon storage. New research published earlier this month shows that marshes on coastlines subject to sea level rise stored 2 to 4 times more carbon in the top 20cm (8 in) of sediment, and five-to-nine times more carbon in the lower 50-100cm (c.20-40in) of sediment, compared to salt-marshes on coastlines where sea level was more stable over the same period (Rogers et al., 2019).
2. Mangroves raise coastal topography. The organic carbon that is accumulated in mangrove forests builds the soil elevation of the wetland, providing a mechanism to combat sea levels rise.
3. Mangroves create low-cost water treatment and offer unique amenities for resorts and residences. Many coastal resorts and developments are built in beautiful places often where mangroves are abundant. Incorporating mangroves into the property design can provide protection and filtration benefits, including waste-water treatment, to increase the ecological and aesthetic value of the property at no additional cost. In addition, mangroves provide low-cost, beautiful landscaping, while at the same time providing unique tourist and visitor amenities. Mangrove landscaping provide low-maintenance and spectacular grounds, such as those pictured below in English Harbour, Antigua. Mangrove forests help to maintain the calmness of coastal waters and lagoons creating ideal places for kayaking, paddle-boarding and exploring wildlife, offering visitors and guests a unique amenity.

Of course mangroves have many other recognized values:

• Their root systems are a natural barrier against storms and sea level rise.
• They trap land and river sediment, helping to protect coastlines, slow erosion, and prevent harmful runoff from damaging corals and seagrass.
• They are vital for biodiversity and fisheries and their wood is extensively used by communities.

The combined the goods and services provided by mangroves are conservatively estimated to be worth US$186 million each year. Studies are continuing to be conducted to determine the comprehensive ecological and cultural value of mangroves around the world. They are a vital natural resource that can serve as an integral component of coastal development projects into the future.

Historic Admiral's Inn in Nelson's Dockyard, English Harbour Antigua. This Inn maintains the mangroves that protect the coastal development and create a beautiful natural landscape, showing how form, function and beauty work as one.

​Cited: Rogers, K., et al (2019). Wetland carbon storage controlled by millennial-scale variation in relative sea-level rise. Nature, 567 (7746), 91–95. https://doi.org/10.1038/s41586-019-0951-7