FUNCTIONAL HABITAT CHRONOLOGY ANALYSIS: INTEGRATING LIFE STAGES HABITAT REQUIREMENTS AND HABITAT CONNECTIVITY FOR ESTIMATING RIVER PRODUCTION POTENTIAL (#12)
In order to complete their life cycle, fish need to access an orderly sequence of different habitat types whose characteristics fulfil the requirements associated to particular life functions or life stages. Heterogeneity of physical habitat is therefore essential to create a mosaic of complementary habitats. Connectivity between these habitats is also required for a fish to freely move between them in the appropriate chronological order. The functional habitat chronology approach we present is based on the idea that the value of a complementary habitat decreases with distance and becomes zero if it is too far to be reached by an individual or if access is precluded by an impassable obstacle. Applying this principle chronologically throughout the life history of a fish produces a chain of successive suitable habitat patches connected to each other based on the mobility of the fish at the time the movement is required. In this presentation, the usefulness of the approach is illustrated using examples from Atlantic salmon (Salmo salar) rivers from Québec (Canada). An automated method was developed to delineate reach types and functional habitat patches from hyperspatial remote sensing imagery and digital elevation models. Connectivity between functional habitats was modeled using a least cost approach integrating life-stage specific fish mobility. The results indicate that habitat probability of use values based on connectivity of habitat chronology improves the prediction of fry and parr densities, illustrating the potential of the method to produce better estimates of river production potential values used to manage fish populations.