Central Mangrove Wetland is Cayman’s heart and lungs

The District of Bodden Town is home to the Central Mangrove Wetland, considered by some to be the ecological heart of Grand Cayman, home to a wide range of animals, birds and aquatic life. 

This large area of mangrove forest extends from the shores of the North Sound through to North Side, and is deemed critical to many important natural processes. 

While it covers about 8,500 acres, the National Trust notes that, of that area, about 1,500 acres of the Central Mangrove Wetland is protected through the Marine Parks Law, forming part of the Environmental Zone which has been in effect for Little Sound and its fringing mangroves since 1986. The Trust has to date purchased 765 acres as part of its Central Mangrove Wetland Reserve. 

Currently research is being done on the ecosystem services, or the services that natural areas provide for people, provided by key regions of the islands. Preliminary studies have shown that the Central Mangrove Wetland, along with the Mastic forest, provides the most ecosystem services in Cayman, which include providing resilience in the face of tropical storms and the effects of climate change; provision of crops, livestock and fish; contributing to stable precipitation patterns; and providing a source for water. 

“Perhaps one of the most economically important reasons to protect our natural areas is to maintain the high quality of our tourism product,” noted the National Trust’s Cathy Childs. 

“Looking in detail at each of these services, we can try to quantify them so that we can make well-informed decisions as to how the country will develop in a sustainable way,” she added. 

The Trust notes in its background information on the Central Mangrove Wetland that the area is part of a large-scale water-flow system, which filters and conditions the surface water and shallow groundwater that enters the North Sound. 

Tidal flushing of the mangrove fringes and the periodic spillover of rainwater out of the wetland into the North Sound transports nutrients that form the base of the complex food chain that supports all aquatic life. This includes turtle grass, shrimp, fish and crustaceans including lobsters and reef dwellers. 

“The entire living system of North Sound is inextricably linked to the Central Mangroves, and would collapse if the Wetland were ever destroyed,” notes the background information. 

“Except for areas of open water, it is covered by a canopy of trees, which absorb sunlight and radiate part of that energy as heat, warming the air near the leaves. 

“The same air also becomes saturated with water vapor, evaporating from the leaves’ breathing pores and from the ponds below … which forms rapidly developing clouds, which are carried west by the prevailing winds and dump rain over the central and western districts of Grand Cayman.” 

It has been determined that thanks to this process, western Grand Cayman’s rainfall is 40 percent greater than in the eastern districts, which though drier, have access to fresh water from water lenses beneath the ground’s surface. 

The Central Mangrove Wetland helps maintain these water lenses by acting as a barrier, stopping accumulated rainwater and fresh water contained in the water lenses on higher ground from flowing into the sea, thus maintaining water supplies in Cayman’s drier areas. 

“Mangrove canalization and development in western Grand Cayman has already shown how vulnerable our agriculture and groundwater supplies are to the destruction of neighboring wetlands,” the Trust notes. 

The Central Mangrove Wetland has also been designated by an “Important Bird Area” by BirdLife International due to the rare birds which call it home. 

The Trust notes that West Indian whistling duck, least terns, Grand Cayman parrots, snowy egrets and many other native birds depend on the Central Mangrove Wetland for food, shelter and as a place to breed. 

The Trust also notes the role the Central Mangrove Wetland plays in storing carbon, which is normally released into the atmosphere as carbon dioxide through the burning of fossil fuels. This storage happens via the slow buildup of peat, produced by very slowly decomposing plant matter. 

Sea levels in the Caribbean have been rising since the last Ice Age, and, according to the Trust, “over thousands of years, thick layers of mangrove peat have been deposited in areas where the underlying rock is now far below sea level. The Central Mangrove Wetland is laying down about three million cubic feet of salt-saturated mangrove peat every year in this way. 

“The peat is very rich in carbon, originally collected as carbon dioxide gas absorbed from the atmosphere by the mangroves (all plants absorb carbon dioxide, releasing oxygen as they grow). So the way in which mangrove wetlands develop during periods of rising sea level actually removes carbon dioxide gas from the atmosphere.” 

An aerial view of the Central Mangrove Wetland.
An aerial view of the Central Mangrove Wetland.
Russell A. Mittermeier

A popular way to explore the fringes of the Central Mangrove Wetland is by kayak.

A popular way to explore the fringes of the Central Mangrove Wetland is by kayak.