Mangrove trees live in most of the sub-tropical and tropical countries of the world, growing along sheltered coastlines. Mangrove wetlands form an important link between the land and the sea. In Cayman, three types of mangroves typically live in wetlands: red, white and black, each of which has evolved unique characteristics to put up with levels of salt and a lack of oxygen that would normally kill other plants. These woody, seed-bearing plants range in size from tall trees to small shrubs. Mangroves fulfill many important functions for our islands: providing the basis of the food web upon which all our marine creatures feed, acting as a nursery for small fish and juveniles, protecting land from the effects of storms and surges and filtering the water of sediment resulting in the spectacular crystal-clear waters surrounding Cayman.

Mangroves have developed remarkable adaptations to enable them to survive in, what in plant terms would be considered, a hostile environment. Black and white mangroves make use of special roots that grow vertically above the ground to act like snorkels. These roots allow the tree to absorb oxygen from the air when the ground is completely awash with salt water and the soil is low on oxygen. Black mangroves also excrete salt through their leaves. On a dry day, it is actually possible to see the salt crystals on the leaves. Red mangroves are the best adapted for living in salt water and can usually be found nearest the sea, often actually growing in the water. The roots of red mangroves give the impression of a tree on legs or stilts; they literally allow it to 'stand' in the water. Their means of reproduction is unlike any other: they have large seeds called 'propagules', which look like darts, hanging from the ends of their branches. Each propagule is a small plant with roots already growing. When it falls from the parent tree, it can either grow directly in the muddy sediment or float along until the root end weighs it down, positioning it right-way-up and ready to grow.

Mangroves provide many important functions vital to the health of Cayman's environment, including providing an ideal habitat for birds, fish and a wealth of different invertebrate species. Cayman's parrots love to nest in the hollow trunks of dead black mangrove trees. Fish make their homes amongst the tangled roots of red mangroves, hiding from larger fish and feeding on smaller fish and creatures that also make their homes in the tree roots. Baby turtles and lobsters and other juveniles thrive in the sanctuary offered by the root systems and shallow water areas. Invertebrates, such as the mangrove oyster, crabs, snails and shrimps, actually make their homes on the submerged mangrove trees and roots, making these areas a spectacularly diverse and colourful environment for snorkeling.

In addition to the habitat they provide, mangrove wetlands also perform numerous other essential functions. The dense and extremely strong root systems form a perfect protection against the large waves and storm surges that Cayman can experience during hurricanes and other storms. On a day-to-day basis, the roots help to stabilise muddy and soft sediments that would be stirred up by wave activity causing shoreline erosion and murky waters devoid of marine life. They dampen the wave energy, subduing large waves and protecting our coastlines. Mangrove wetlands act like large sponges absorbing vast quantities of fresh water from heavy rains and releasing it slowly and harmlessly into the marine environment. This means that by the time rain water reaches the reef, it has been filtered by the mangroves and the sediment stirred up by the storm has settled. Mangrove ecosystems are also important providers of nutrients that feed into surrounding ecosystems, thereby making them healthier and more productive.

In the Cayman Islands, the major problem affecting mangrove habitats is humanity's desire to convert mangrove areas into residential, commercial and industrial developments. During the last 25 to 30 years, rapid growth of Cayman's population and tourism industry have resulted in a substantial amount of land development on Grand Cayman in particular. One of the major problems is the destruction of mangrove swamps to accommodate canal and waterfront real estate.

The implementation of Marine Parks has afforded some of Cayman's mangroves limited protection from the onslaught of development. However, the only current forms of protection offered to the mangroves themselves are the designated mangrove buffer zones, National Trust ownership and some Animal Sanctuaries. Clearly, it is time for us to critically evaluate Cayman's priorities and give due thought to the immensely important status of our mangroves.

Last Updated: 27 Jun 2012