The Malagarasi drainage in western Tanzania is among the world’s most important wetland regions. The area contains biodiversity of regional and international significance but until this expedition its biological and physical characteristics had received almost no scientific attention. Our primary aims were to survey each of the primary biotopes of the Malagarasi Basin to provide baseline quantitative data on 1) aquatic biodiversity and 2) limnological functioning. The scientific data we generated is an important first contribution to understanding this imperiled ecosystem. Contacts with regional policy makers, some established during the expedition, will also help facilitate dissemination and utilization of our survey results for informing on conservation priorities in the region.
Accomplishments: We sampled approximately 40 sites along the main flow of the Malagarasi River proper, and additionally associated shallow Lakes Sagara & Nyamagoma, small stream and delta inflows into Lake Tanganyika, other Malagarasi tributary rivers such as the Lugufu, Ruchugi, Ugalla, Makere and Igombe.
Biodiversity collections focused on fish, herps (amphibians & reptiles) and molluscs, with additional collections of aquatic insects, crustaceans and diatoms – new species were found among most groups. Limnological sampling included physical parameters, water chemistry and productivity analyses indicating anthropogenic impacts throughout the region. Our aquatic surveys of the remote Igamba Falls area are apparently the first of their kind and revealed a number of new fish and mollusc species, making this site not only of special interest, but also of special concern as it is under discussion for hydropower installation. Our aerial photographic survey was the first for the river drainage and provides detailed information on habitat use in the areas surveyed.