Ilkka Aulis Hanski (14 February 1953 – 10 May 2016) was a prominent Finnish scientist best known for his work in ecology. He was a professor at the University of Helsinki and led long-term field studies that turned abstract population theory into empirically testable models. His research focused on how populations persist in fragmented landscapes and on practical consequences for biodiversity conservation.
Core ideas and models
Hanski helped refine and popularize the modern concept of the metapopulation: a set of local populations connected by dispersal across habitat patches, where local extinctions and recolonizations determine regional persistence. He formulated and applied quantitative models—including the incidence function approach—that relate patch size, isolation and colonization–extinction rates to the probability a patch will be occupied. He also articulated ideas such as the core–satellite species pattern, explaining why some species occupy many sites while others remain rare and localized.
Field studies and methods
A distinguishing feature of Hanski's work was the combination of intensive field monitoring, experimental manipulations and mathematical models. His long-term studies of the Glanville fritillary butterfly (Melitaea cinxia) in the Åland Islands provided one of the clearest empirical demonstrations of metapopulation dynamics. These projects integrated mark–recapture, genetics, landscape mapping and demographic analyses to test theoretical predictions and to measure dispersal, extinction risk and rescue effects.
Applications and influence
- Conservation biology: Hanski's findings clarified how habitat fragmentation affects species persistence and informed reserve design and habitat-management strategies.
- Theoretical ecology: his models became standard tools for predicting patch occupancy and for interpreting spatial patterns of biodiversity.
- Training and collaboration: he mentored many researchers and fostered interdisciplinary work across population biology, genetics and landscape ecology.
Hanski authored widely cited papers and a comprehensive synthesis on metapopulation ecology that remains a key reference for students and practitioners. His combination of rigorous theory with careful empirical work influenced how ecologists assess extinction risk and manage fragmented habitats.
Born in 1953, Hanski spent much of his career at the University of Helsinki. He died after a long illness on 10 May 2016 in a hospital in Helsinki, aged 63. His research legacy continues to shape both basic ecology and applied efforts to conserve species in changing, fragmented landscapes.