Incorporating hydrodynamics into ecohydraulics: the role of turbulence in the swimming performance and habitat selection of stream-dwelling fish

The complexity and dynamism of river systems, the strength of their biophysical linkages and the need to respond to adverse anthropogenic impacts has led to the emergence of hydroecology as a key area of interdisciplinary research. A sub-discipline of hydroecology known as ecohydraulics has emerged from the scientific literature in recent decades and, as a contemporary science, has its roots in the hydraulic stream ecology paradigm. Ecohydraulics relies on the assumption that flow forces are ecologically relevant (i.e. that they influence the fitness of individual organisms and, therefore, the structure and function of aquatic communities). It lies at the interface of hydraulics and ecology where new approaches to research are required to reconcile the contrasting conceptual frameworks underpinning these sciences, which can be seen respectively as Newtonian (reductionist) and Darwinian (holistic). River habitat is structured at a number of scales but it is at the microscale (<10−1 m) of the hydraulic environment where reductionist explanations for ecological phenomena are most often sought.