As the climate warms, many species’ habitats are expected to shrink, shift, or otherwise change quicker than some species populations can adjust, leading to loss of biodiversity. One possible response to this problem is assisted migration—intentional translocation of species outside their historic ranges to mitigate biodiversity losses caused by climate change. While this idea has been around for decades, it has recently become the subject of a fierce debate in the academic literature. An interdisciplinary team of IRIS researchers has just published a ground-breaking study that takes stock of the burgeoning academic literature on this topic and identifies possible avenues toward scholarly consensus on how to address what might otherwise become an intractable ethical and policy problem.
Assisted migration is seen by many scholars as pitting two conservation goals against each other: the preservation of a single species against extinction versus the protection of ecological communities against the risks posed by introduced species. While assisted migration might help to save individual species, trans-located species might have impacts similar to invasive alien species including uncontrolled population growth and negative impacts on resident species. Assisted migration also conflicts with established conservation approaches favouring in situ management and maintenance of existing species ranges.
Lead author Dr. Nina Hewitt (a biogeographer and IRIS Senior Fellow) and her coauthors conducted a bibliometric study of the existing academic literature on assisted migration, classifying it in terms of study methods, geographic and taxonomic (species) focus, and degree of knowledge transfer from the natural sciences to other academic disciplines and non-academic sectors. They show that the volume of scholarly writing on assisted migration has exploded in the past three years, addressing a wide range of regions and species. Much of it, however, takes the form of commentary rather than original scientific research, and the rate of knowledge transfer to the social sciences and humanities appears low.
The article’s main contribution is to analyze the scholarly debate about the desirability and feasibility of assisted migration as a response to climate change. At a general level, a majority of the papers reviewed were generally supportive of using or at least considering assisted migration, but a closer examination shows that the debate is intensifying. To make sense of the variety of positions in the debate, the article distinguishes between arguments about the direct ecological and socio-economic benefits and risks of AM, on one hand, and arguments or counter-arguments addressing other issues such as knowledge gaps, uncertainties, planning and implementation, on the other. It presents all of these arguments and their key inter-relations schematically in a one-page, easy to read figure.
The coauthors argue that conceptualizing the debate in these terms puts the focus on what is ultimately at stake—the relative benefits and risks of assisted migration—and provides a common basis for both proponents and opponents to navigate the key issues.
While recognizing that the assisted migration debate raises difficult ethical, political and scientific challenges, the article identifies several recommendations with potential to advance the debate. The most innovative of these recommendations is the suggestion that people on both sides of the debate might be able to agree that the urgency of the climate change problem demands a proactive approach that could combine risk-averse, in situ strategies such as habitat creation at range margins with unconventional, risk-tolerant strategies such as assisted migration.
The research was funded by the Canadian Foundation for Climate and Atmospheric Sciences. Aside from Dr. Hewitt, the co-authors were Dr. Nicole Klenk (IRIS Senior Fellow), Dr. Andrea Smith (IRIS Senior Fellow), Professor Dawn Bazely (IRIS Director and York University Biology Department) Professor Norman Yan (IRIS Core Faculty and York University Biology Department), Professor Stepan Wood (IRIS Acting Director and Osgoode Hall Law School), Dr. James MacLellan (IRIS Senior Fellow and York Faculty of Environmental Studies), Professor Carla Lipsig-Mummé (Director of IRIS-affiliated Work in a Warming World program and York University Social Science Department) and Irene Henriques (IRIS Core Faculty member and Schulich School of Business).
The article, “Taking Stock of the Assisted Migration Debate,” appears in the latest issue of Biological Conservation (volume 144, pages 2560-72).
