To properly conserve, restore and manage riverine ecosystems and the services they provide, it is pertinent to understand their functional dynamics. Growing human populations and high dependency on natural resources in developing countries have exerted pressure on land and water resources. However, there is a major knowledge gap concerning the influence of human activities on the functioning of tropical rivers in terms of organic matter processing and energy sources supporting riverine consumers.This thesis explores the functioning of tropical upland streams and savanna rivers by assessing...