FLORAL AND FAUNAL DIFFERENCES BETWEEN FRAGMENTED AND UNFRAGMENTED BAHAMIAN TIDAL CREEKS

We characterized biota in two unfragmented and two fragmented mangrove-lined tidal creeks on Andros Island, Bahamas, in May 2003, to examine particular effects of tidal creek fragmentation by road blockage. Total number of plant and fish species was significantly different between fragmented and unfragmented creeks, and species composition was significantly different both between unfragmented and fragmented creeks, and between downstream and upstream areas within fragmented creeks. More reef-associated, economically important and ecologically critical plant, macroinvertebrate, and fish species were observed in unfragmented tidal creeks, while fragmented creeks contained: 1) plant species typical of higher elevation estuarine habitat, 2) terrestrial and aquatic macroinvertebrate species typical of upland habitats, 3) macroinvertebrate species adapted to low flow, and 4) temperature-and saline-tolerant macroinvertebrate and fish species. Furthermore, fragmented tidal creeks had different size distributions of common organisms, e.g., smaller sizes of two economically important fish species (Lutjanidae). This study suggests that fragmentation of tidal creeks and the subsequent loss of hydrologic connectivity influences the diversity and composition of aquatic flora and fauna, and may considerably inhibit nursery function and other ecosystem services provided by these coastal systems. These data also provide a baseline with which community- and ecosystem-level responses to restoration of hydrologic connectivity in fragmented tidal creeks will be assessed.