Frontiers in Metapopulation Biology: The Legacy of Ilkka Hanski

This review of metapopulation biology has a special focus on Professor Ilkka Hanski's (1953-2016) research. Hanski made seminal contributions to both empirical and theoretical metapopulation biology throughout his scientific career. Hanski's early research focused on ecological aspects of metapopulation biology, in particular how the spatial structure of a landscape influences extinction thresholds and how habitat loss and fragmentation can result in extinction debt. Hanski then used the Glanville fritillary system as a natural laboratory within which he studied genetic and evolutionary processes, such as the influence of inbreeding on extinction risk and variation in selection for dispersal traits generated by landscape variation. During the last years of his career, Hanski's work was in the forefront of the rapidly developing field of eco-evolutionary dynamics. Hanski was a pioneer in showing how molecular-level underpinnings of trait variation can explain why evolutionary change can occur rapidly in natural populations and how these changes can subsequently influence ecological dynamics.