Dunes are one of the most important coastal ecosystems in the world, because they provide protection for beaches and coastal vegetation.
Because of their vulnerability to the effects of climate change, atmospheric phenomena and human activity, dunes are very fragile places. Deserts, lakes and ocean shores, where winds tend to blow the hardest and in a single direction, are the most suitable environments for the formation of these ridges of loose sand. They are party of a dynamic equilibrium that makes it possible for beaches to exist, and have seasonal changes with notable differences in the summer and winter.
In Cuba, the dunes on the cays that are part of the Jardines del Rey archipelago north of the central province of Ciego de Ávila, principally Cayo Coco and Cayo Guillermo, have very unique characteristics, because they are stabilized hills that do not migrate.
According to experts, these dunes emerged during a recent geological period, the Holocene Epoch, and are believed to be the oldest in Cuba's northern cays. Their genesis is related to the receding waters of the sea, which left large areas of sand exposed to the drying action of the sun. Subsequently, the winds dragged the sand inland on the beach, where dunes accumulated over the years, forming beautiful natural reserves in Loma del Puerto, on Cayo Coco, and Playa Pilar, on Cayo Guillermo.
The dunes located parallel to Playa Pilar stand 15 meters above sea level and are believed to be the tallest in the Caribbean. Moreover, they are wellknown in the region, given that they are part of one of the most beautiful beach landscapes in the world. In Loma del Puerto, the dunes stand 10 to 14 meters tall, making them the second-tallest in the region, and they are part of the Cayo Coco Central-West Environmental Reserve, a protected area that harbours wildlife and that is preserved in its natural state.
These are vegetated dunes, or ridges that are parallel to the beach and anchored by vegetation, generally endemic flora that forms a narrow strip and includes mangroves, herbaceous plants, bushes and creepers, such as brittlebush, beach morning glory, inkberry, coastal ragweed, and purslane. It is also very common to find field sandbur, with its sharp, shiny burs.
According to Adán Zúñiga, director of the Cayo Coco Coastal Ecosystems Research Center, studies have shown that the dunes maintain their physical parameters and levels of vegetation that classify as endemic.
They also serve as natural conservation reserves; when the beaches lose sand due to coastal flooding or powerful winds, the dunes are a source of replenishment.
Despite their vital function in beach conservation, dunes are very fragile because they are composed of loose elements that come into constant contact with other very dynamic elements such as air, earth and water.
For tourists, the dunes and their accompanying flora and fauna —including dozens of species of birds— tend to be one of the most striking and attractive features of the beautiful Jardines del Rey tourist destination. To protect these ecosystems, wooden boardwalks on piles are being built to run from hotels and ranchones (outdoor restaurants) to the beaches and swimming areas on both Cayo Coco and Cayo Guillermo.
Another important activity that is part of the different biodiversity conservation plans underway in the Sabana-Camagüey archipelago is the reforestation of dunes with endemic plants. This project is being carried out by Cuban scientists with support from the United Nations Development Programme.