Deforestation-induced phenotypic change in an African cyprinid: Adaptation, plasticity and implications for ecosystem function

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Deforestation progresses at alarming rates around the world. The negative effects of forest loss on freshwater rivers and lakes (changes in water chemistry, sedimentation, etc.) threaten the sustainable harvest of the services that we derive from freshwaters. It is therefore of prime importance to study the interaction between land use and aquatic biological communities. Biologists have long known that the presence or absence of particular species in an ecosystem can dramatically alter how this ecosystem functions. Very recently, ecologists have started thinking that small differences across populations of the same species can also affect ecosystem functioning. By looking at the ecosystem-level consequences of the variation between populations of one species caused by different degrees of deforestation, my research aims at bridging two very different but equally important topics: the impact of deforestation on aquatic organisms and the consequences of population differences for ecosystem function. I will address these questions using the Ugandan fish Barbus neumayeri, as this model organism presents a variety of characteristics that makes it advantageous from an experimental perspective, and because there is a complete lack of studies on tropical rivers. I will use different techniques in both the laboratory and the field, including morphology analysis, diet analysis, behavioral experiments in tanks, and enclosure experiments in rivers. Apart from addressing theoretical questions for which there is currently much interest, these experiments have the practical application of examining how deforestation affects aquatic organisms and river function. In addition to helping freshwater management in Uganda, a country in great need of expert knowledge, this research addresses general principles applicable to any freshwater ecosystem worldwide, and will inform us of the consequences of deforestation on the functioning of our own Canadian rivers.