Sedimentation resulting from riparian deforestation has a wide range of detrimental eVects on aquatic biodiversity, but predicting the full consequences of such disturbances requires an understanding of the ecosystem's key functional components. We investigated the ecology and response to sedimentation of the diverse, endemic freshwater crabs of Lake Tanganyika, which may occupy important positions in littoral foodwebs. Our surveys revealed crab distribution patterns to be patchy, and that crabs can be locally abundant (0-28 individuals m ¡2 ). Crab densities decreased with depth and the dry mass of crab assemblages ranged from 0.0 to 117.7 g m ¡2 . Comparisons among sites revealed signiWcant eVects of sedimentation on crab assemblage evenness, but provided no evidence that sedimentation has altered densities, incidence or species richness. The resilience of crabs to sedimentation might be related to their intraspeciWc dietary breadth. Stable isotope data ( 13 C and 15 N) from crabs and their potential food resources indicated diVerences in trophic roles among endemic crab species. Overall, crabs occupy higher trophic positions than most other invertebrates, and they draw upon both benthic and planktonic energy pathways. The high biomass and top-predator status of some crab species suggests the potential for cascading eVects on organisms lower in the food web.