Assessing the impact of damming on river fishes: going beyond taxonomy ; Avaliação do impacto de barragens em peixes de água doce: para além da taxonomia

Doutoramento em Biologia e Ecologia das Alterações Globais ; Freshwater ecosystems have been severely affected by the expansion of human development in the last century. Freshwater biodiversity is consequently in sharp decline due to increased demand over limited water resources. Degradation and loss of ecosystem services, as well as financial consequences of ecological freshwater problems are creating pressure for a change in attitude from governments and stakeholders concerning strategies for conservation management. Damming is one of the major causes of ecological change in rivers associated with human development. Knowledge of their impact on freshwater ecosystems has been mostly described from the perspective of taxonomic changes. However, this approach provides little information about biological function. Alternative and simpler ways to assess the impact of damming are crucial since the constructions of dams are in expansion, especially in tropical regions where the lack of taxonomical and ecological knowledge about fish species impose an obstacle to effective mitigation measures. A trait-based approach holds the promise to increase our mechanistic understanding of biological responses to disturbed habitats; it transcends taxonomy and it can be applicable across large geographic units. Fishes have a history as biological indicators of environmental quality. They are useful for testing new approaches as their responses to varied anthropogenic disturbances are relatively well documented and their sensitivities to the health of surrounding aquatic environments form one of the basis to monitor environmental degradation. The usage of fish traits as an alternative approach to assess impacted rivers is presented in a critical review where their potential advantages over traditionally used methods are discussed as well as their challenges. The aim of this study was to assess the impact of damming on fish fauna after dam closure using taxonomic and trait-based approaches. The experimental design considered both ...