Coastal Habitat Mapping Along the Tanzania/Mozambique Transboundary Area Using Landsat 5 TM Imagery

Abstract

Abstract—Landsat 5 TM imagery was used to study the distribution of coastal habitats along the Eastern African coast, from Mnazi Bay (Tanzania) south to Pemba Bay (Mozambique), across the mouth of the Ruvuma estuary and the Quirimbas archipelago. Eight classes of coastal habitats, adapted from the Ramsar convention classification –intertidal, and subtidal –were mapped at a coarse descriptive resolution using an unsupervised classification procedure. Results for 1995 and 2005 are presented, for the entire coastline, and in detail, for the areas of the Ruvuma estuary, Palma, Mocímboa da Praia, and Ibo Island. Results were evaluated using data from ground truthing excursions during 2006. For each date, over 3,300 km2 of coastal habitats were classified. The classes with the largest coverage were “permanent shallow marine water” (>1,500 km2), followed by “intertidal flats” (>650 km2), “mangroves”, and “coral reefs” (covering > 320 km2 each). Estimated overall thematic accuracy for 2005 exceeded 70%. The paper discusses a number of aspects that may influence the accuracy of the final classification and limit time-change analysis to a few of the habitats considered. The resulting spatially referenced thematic maps constitute a useful tool to aide management actions along this coast and are a valuable reference point for conservation and research planning.

Keywords: Remote-sensing, satellite imagery, classification accuracy, tropical coastal habitats, transboundary, Mozambique, Tanzania