Abstract
The Red Sea is a large marine ecosystem in which biological research has been considerable but integrated environmental assessment insubstantial. Approximately 1400 coastal and offshore (i.e. island) sites in the Saudi Arabian Red Sea were examined and an analysis of ordinal data on the abundance of ecosystems and magnitude of human uses/environmental impacts was conducted. Mangroves, seagrasses, other floral groups and terrestrial mammals were significantly more abundant at the coastal sites than offshore. The coastal sites were also impacted most heavily, while reefs, birds, turtles and marine mammals were significantly more abundant in offshore areas. Latitudinal trends include significantly increased abundance of mangroves and seagrasses (and other flora) towards the southern Red Sea, and a decrease in abundance of reefs. Significantly higher levels of beach oil were encountered towards the northern Red Sea, probably reflecting its greater proximity to the Gulf of Suez. Cluster analysis using all biological data revealed distinctive groupings which separated according to latitude. The biogeographic patterns are comparable to those observed in previous studies for seagrasses and other communities. Using a relational database, applications of the findings to coastal management include creation of environmental profiles for particular sites or sectors, identification of resource-use conflict areas, and selection of representative sites for protected areas. Comparison with data from a complementary investigation in the Arabian Gulf indicates that the Red Sea is less perturbed by human activities than the Arabian Gulf. However, it is also evident that the Red Sea is no longer a pristine environment.