Development of a Geographical Information System for the marine resources of Rodrigues

A Geographical Information System (GIS) was developed to integrate data on the distribution of biodiversity, environmental factors governing distributions, human activities such as fishing and Marine Protected Area (MPA) planning. The GIS was established because there is a paucity of collated information on the marine resources of Rodrigues, western Indian Ocean, hampering marine environmental protection. The GIS was established in MapInfo software using a Landsat satellite image as a base layer. Field surveys were undertaken at 183 sites throughout the lagoon and reefs to ground-truth the satellite image. A hierarchical biotope classification was developed and 42 biotopes were described within four habitat groups (Coral, Sand and rubble with mixed vegetation, Lagoon muds, and Consolidated limestone), and used to create a biotope map layer. A relational database was linked to the GIS to store and display site-based data, including biotope descriptions and photographs, species lists and illustrations, and environmental data. GIS output is exemplified by thematic maps illustrating species richness and habitat at sites, percentage cover of benthic life forms, data collection sites and depths, and number of octopus and potential octopus refugia. The GIS was also used to identify the biotopes protected by proposed Marine Protected Areas, illustrating that some existing MPAs may be ineffective and proposed boundaries could protect more than 30% of the shallow marine environment of Rodrigues. The GIS provides a useful tool to establish the conservation and sustainable use of the island's marine resources, and the highly visual and interactive system should prove valuable for education and public awareness purposes.