Geomorphology and Development of Mangrove Swamps, Grand Cayman Island, West Indies

Mangrove swamps occupy extensive areas on Grand Cayman in the West Indies. The vegetational and geomorphological characteristics of swamps in two areas, Barkers Peninsula and West Bay Peninsula, are described, and tentative models of the development of swamps in these areas are proposed. The swamplands are composed of three species of mangrove, Rhizophora mangle, Avicennia germinans and Laguncularia racemosa. While a broad zonation of these species can be recognized, the vegetation pattern is complicated by stands of swampland species of distinct physiognomy or by associations of species. The sequence of sedimentary units identified in cores taken within and adjacent to the mangroves is transgressive and records Holocene submergence of the island. Observations of stratigraphy and sediment thickness in these areas reveal that the development of mangrove swamps has been controlled principally by the relationship between land and sea, and that expansion of mangroves has been determined by the topography of the pre-Holocene bedrock surface and prevailing wave and current energy conditions. This extension of mangroves has generally been in a landward direction, into previously terrestrial environments, and has rarely been to seaward.